/*
* Copyright 2015 Hippo Seven
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hippo.widget;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.os.Build;
import android.os.Bundle;
import android.os.Parcelable;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.view.FocusFinder;
import android.view.InputDevice;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.view.animation.AnimationUtils;
import android.widget.EdgeEffect;
import android.widget.FrameLayout;
import android.widget.ScrollView;
import com.hippo.nimingban.R;
import java.util.List;
public class BothScrollView extends FrameLayout {
private static final String TAG = BothScrollView.class.getSimpleName();
private static final String KEY_SUPER = "super";
private static final String KEY_SCROLL_X = "scroll_x";
private static final String KEY_SCROLL_Y = "scroll_y";
private static final int ANIMATED_SCROLL_GAP = 250;
private static final float MAX_SCROLL_FACTOR = 0.5f;
private long mLastScroll;
private final Rect mTempRect = new Rect();
private SmoothOverScroller mScroller;
private EdgeEffect mEdgeGlowLeft;
private EdgeEffect mEdgeGlowRight;
private EdgeEffect mEdgeGlowTop;
private EdgeEffect mEdgeGlowBottom;
/**
* Whether arrow scrolling is animated.
*/
private boolean mSmoothScrollingEnabled = true;
private int mTouchSlop;
private int mMinimumVelocity;
private int mMaximumVelocity;
private int mOverscrollDistance;
private int mOverflingDistance;
/**
* Position of the last motion event x.
*/
private int mLastMotionX;
/**
* Position of the last motion event y.
*/
private int mLastMotionY;
/**
* True when the layout has changed but the traversal has not come through yet.
* Ideally the view hierarchy would keep track of this for us.
*/
private boolean mIsLayoutDirty = true;
/**
* The child to give focus to in the event that a child has requested focus while the
* layout is dirty. This prevents the scroll from being wrong if the child has not been
* laid out before requesting focus.
*/
private View mChildToScrollTo = null;
/**
* True if the user is currently dragging this ScrollView around. This is
* not the same as 'is being flinged', which can be checked by
* mScroller.isFinished() (flinging begins when the user lifts his finger).
*/
private boolean mIsBeingDragged = false;
/**
* Determines speed during touch scrolling
*/
private VelocityTracker mVelocityTracker;
/**
* When set to true, the scroll view measure its child to make it fill the currently
* visible area.
*/
private boolean mFillViewport;
/**
* ID of the active pointer. This is used to retain consistency during
* drags/flings if multiple pointers are used.
*/
private int mActivePointerId = INVALID_POINTER;
/**
* Sentinel value for no current active pointer.
* Used by {@link #mActivePointerId}.
*/
private static final int INVALID_POINTER = -1;
private Bundle mSavedState;
/**
* Vertical scroll factor cached by {@link #getVerticalScrollFactor}.
*/
private float mVerticalScrollFactor;
/**
* true if this view has been through at least one layout since it
* was last attached to or detached from a window.
*/
private boolean mLaidOut;
public BothScrollView(Context context) {
super(context);
init(context, null, 0, 0);
}
public BothScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context, attrs, 0, 0);
}
public BothScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context, attrs, defStyleAttr, 0);
}
private void init(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
initBothScrollView(context);
final TypedArray a = context.obtainStyledAttributes(
attrs, R.styleable.BothScrollView, defStyleAttr, defStyleRes);
setFillViewport(a.getBoolean(R.styleable.BothScrollView_fillViewport, false));
a.recycle();
}
private void initBothScrollView(Context context) {
mScroller = new SmoothOverScroller(context);
setFocusable(true);
setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
setWillNotDraw(false);
final ViewConfiguration configuration = ViewConfiguration.get(context);
mTouchSlop = configuration.getScaledTouchSlop();
mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
mOverscrollDistance = configuration.getScaledOverscrollDistance();
mOverflingDistance = configuration.getScaledOverflingDistance();
}
@Override
protected float getLeftFadingEdgeStrength() {
if (getChildCount() == 0) {
return 0.0f;
}
final int length = getHorizontalFadingEdgeLength();
final int scrollX = getScrollX();
if (scrollX < length) {
return scrollX / (float) length;
}
return 1.0f;
}
@Override
protected float getRightFadingEdgeStrength() {
if (getChildCount() == 0) {
return 0.0f;
}
final int length = getHorizontalFadingEdgeLength();
final int rightEdge = getWidth() - getPaddingRight();
final int span = getChildAt(0).getRight() - getScrollX() - rightEdge;
if (span < length) {
return span / (float) length;
}
return 1.0f;
}
@Override
protected float getTopFadingEdgeStrength() {
if (getChildCount() == 0) {
return 0.0f;
}
final int length = getVerticalFadingEdgeLength();
final int scrollY = getScrollY();
if (scrollY < length) {
return scrollY / (float) length;
}
return 1.0f;
}
@Override
protected float getBottomFadingEdgeStrength() {
if (getChildCount() == 0) {
return 0.0f;
}
final int length = getVerticalFadingEdgeLength();
final int bottomEdge = getHeight() - getPaddingBottom();
final int span = getChildAt(0).getBottom() - getScrollY() - bottomEdge;
if (span < length) {
return span / (float) length;
}
return 1.0f;
}
/**
* @return The horizontal maximum amount this scroll view will scroll in response to
* an arrow event.
*/
public int getHorizontalMaxScrollAmount() {
return (int) (MAX_SCROLL_FACTOR * (getRight() - getLeft()));
}
/**
* @return The vertical maximum amount this scroll view will scroll in response to
* an arrow event.
*/
public int getVerticalMaxScrollAmount() {
return (int) (MAX_SCROLL_FACTOR * (getBottom() - getTop()));
}
@Override
public void addView(View child) {
if (getChildCount() > 0) {
throw new IllegalStateException("BothScrollView can host only one direct child");
}
super.addView(child);
}
@Override
public void addView(View child, int index) {
if (getChildCount() > 0) {
throw new IllegalStateException("BothScrollView can host only one direct child");
}
super.addView(child, index);
}
@Override
public void addView(View child, ViewGroup.LayoutParams params) {
if (getChildCount() > 0) {
throw new IllegalStateException("BothScrollView can host only one direct child");
}
super.addView(child, params);
}
@Override
public void addView(View child, int index, ViewGroup.LayoutParams params) {
if (getChildCount() > 0) {
throw new IllegalStateException("BothScrollView can host only one direct child");
}
super.addView(child, index, params);
}
/**
* @return Returns true this BothScrollView can be scrolled horizontally
*/
private boolean canScrollHorizontally() {
View child = getChildAt(0);
if (child != null) {
int childWidth = child.getWidth();
return getWidth() < childWidth + getPaddingLeft() + getPaddingRight();
}
return false;
}
/**
* @return Returns true this BothScrollView can be scrolled vertically
*/
private boolean canScrollVertically() {
View child = getChildAt(0);
if (child != null) {
int childHeight = child.getHeight();
return getHeight() < childHeight + getPaddingTop() + getPaddingBottom();
}
return false;
}
/**
* Indicates whether this BothScrollView's content is stretched to
* fill the viewport.
*
* @return True if the content fills the viewport, false otherwise.
*/
public boolean isFillViewport() {
return mFillViewport;
}
/**
* Indicates this BothScrollView whether it should stretch its content width and height
* to fill the viewport or not.
*
* @param fillViewport True to stretch the content's width and height to the viewport's
* boundaries, false otherwise.
*/
public void setFillViewport(boolean fillViewport) {
if (fillViewport != mFillViewport) {
mFillViewport = fillViewport;
requestLayout();
}
}
/**
* @return Whether arrow scrolling will animate its transition.
*/
public boolean isSmoothScrollingEnabled() {
return mSmoothScrollingEnabled;
}
/**
* Set whether arrow scrolling will animate its transition.
* @param smoothScrollingEnabled whether arrow scrolling will animate its transition
*/
public void setSmoothScrollingEnabled(boolean smoothScrollingEnabled) {
mSmoothScrollingEnabled = smoothScrollingEnabled;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
// TODO HorizontalFillViewport VerticalFillViewport
if (!mFillViewport) {
return;
}
final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
if (widthMode == MeasureSpec.UNSPECIFIED) {
return;
}
final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
if (heightMode == MeasureSpec.UNSPECIFIED) {
return;
}
if (getChildCount() > 0) {
int childWidthMeasureSpec;
int childHeightMeasureSpec;
final View child = getChildAt(0);
final FrameLayout.LayoutParams lp = (LayoutParams) child.getLayoutParams();
int width = getMeasuredWidth();
int paddingLeft = getPaddingLeft();
int paddingRight = getPaddingRight();
if (child.getMeasuredWidth() < width) {
childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(width - paddingLeft
- paddingRight, MeasureSpec.EXACTLY);
} else {
childWidthMeasureSpec = getChildMeasureSpec(widthMeasureSpec, paddingLeft
+ paddingRight, lp.width);
}
int height = getMeasuredHeight();
int paddingTop = getPaddingTop();
int paddingBottom = getPaddingBottom();
if (child.getMeasuredHeight() < height) {
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(height - paddingTop
- paddingBottom, MeasureSpec.EXACTLY);
} else {
childHeightMeasureSpec = getChildMeasureSpec(heightMeasureSpec, paddingTop
+ paddingBottom, lp.height);
}
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}
}
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
// Let the focused view and/or our descendants get the key first
return super.dispatchKeyEvent(event) || executeKeyEvent(event);
}
/**
* You can call this function yourself to have the scroll view perform
* scrolling from a key event, just as if the event had been dispatched to
* it by the view hierarchy.
*
* @param event The key event to execute.
* @return Return true if the event was handled, else false.
*/
public boolean executeKeyEvent(KeyEvent event) {
mTempRect.setEmpty();
if (!canScrollHorizontally()) {
if (isFocused() && event.getKeyCode() != KeyEvent.KEYCODE_BACK) {
View currentFocused = findFocus();
if (currentFocused == this) {
currentFocused = null;
}
View nextFocused = FocusFinder.getInstance().findNextFocus(this,
currentFocused, View.FOCUS_RIGHT);
return nextFocused != null && nextFocused != this &&
nextFocused.requestFocus(View.FOCUS_RIGHT);
}
return false;
}
if (!canScrollVertically()) {
if (isFocused() && event.getKeyCode() != KeyEvent.KEYCODE_BACK) {
View currentFocused = findFocus();
if (currentFocused == this) {
currentFocused = null;
}
View nextFocused = FocusFinder.getInstance().findNextFocus(this,
currentFocused, View.FOCUS_DOWN);
return nextFocused != null && nextFocused != this
&& nextFocused.requestFocus(View.FOCUS_DOWN);
}
return false;
}
boolean handled = false;
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (event.getKeyCode()) {
case KeyEvent.KEYCODE_DPAD_LEFT:
if (!event.isAltPressed()) {
handled = arrowScrollHorizontally(View.FOCUS_LEFT);
} else {
handled = fullScroll(View.FOCUS_LEFT);
}
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
if (!event.isAltPressed()) {
handled = arrowScrollHorizontally(View.FOCUS_RIGHT);
} else {
handled = fullScroll(View.FOCUS_RIGHT);
}
break;
case KeyEvent.KEYCODE_DPAD_UP:
if (!event.isAltPressed()) {
handled = arrowScrollVertically(View.FOCUS_UP);
} else {
handled = fullScroll(View.FOCUS_UP);
}
break;
case KeyEvent.KEYCODE_DPAD_DOWN:
if (!event.isAltPressed()) {
handled = arrowScrollVertically(View.FOCUS_DOWN);
} else {
handled = fullScroll(View.FOCUS_DOWN);
}
break;
case KeyEvent.KEYCODE_SPACE:
if (event.isCtrlPressed()) {
pageScroll(event.isShiftPressed() ? View.FOCUS_LEFT : View.FOCUS_RIGHT);
} else {
pageScroll(event.isShiftPressed() ? View.FOCUS_UP : View.FOCUS_DOWN);
}
break;
}
}
return handled;
}
private boolean inChild(int x, int y) {
if (getChildCount() > 0) {
final int scrollX = getScrollX();
final int scrollY = getScrollY();
final View child = getChildAt(0);
return !(y < child.getTop() - scrollY
|| y >= child.getBottom() - scrollY
|| x < child.getLeft() - scrollX
|| x >= child.getRight() - scrollX);
}
return false;
}
private void initOrResetVelocityTracker() {
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
} else {
mVelocityTracker.clear();
}
}
private void initVelocityTrackerIfNotExists() {
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
}
private void recycleVelocityTracker() {
if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
}
@Override
public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) {
if (disallowIntercept) {
recycleVelocityTracker();
}
super.requestDisallowInterceptTouchEvent(disallowIntercept);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
/*
* This method JUST determines whether we want to intercept the motion.
* If we return true, onMotionEvent will be called and we do the actual
* scrolling there.
*/
/*
* Shortcut the most recurring case: the user is in the dragging
* state and he is moving his finger. We want to intercept this
* motion.
*/
final int action = ev.getAction();
if ((action == MotionEvent.ACTION_MOVE) && (mIsBeingDragged)) {
return true;
}
/*
* Don't try to intercept touch if we can't scroll anyway.
*/
if (getScrollX() == 0 && !canScrollHorizontally(1) && getScrollY() == 0 && !canScrollVertically(1)) {
return false;
}
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_MOVE: {
/*
* mIsBeingDragged == false, otherwise the shortcut would have caught it. Check
* whether the user has moved far enough from his original down touch.
*/
/*
* Locally do absolute value. mLastMotionY is set to the y value
* of the down event.
*/
final int activePointerId = mActivePointerId;
if (activePointerId == INVALID_POINTER) {
// If we don't have a valid id, the touch down wasn't on content.
break;
}
final int pointerIndex = ev.findPointerIndex(activePointerId);
if (pointerIndex == -1) {
Log.e(TAG, "Invalid pointerId=" + activePointerId
+ " in onInterceptTouchEvent");
break;
}
final int x = (int) ev.getX(pointerIndex);
final int y = (int) ev.getY(pointerIndex);
final int xDiff = Math.abs(x - mLastMotionX);
final int yDiff = Math.abs(y - mLastMotionY);
if (xDiff > mTouchSlop || yDiff > mTouchSlop) {
mIsBeingDragged = true;
mLastMotionX = x;
mLastMotionY = y;
initVelocityTrackerIfNotExists();
mVelocityTracker.addMovement(ev);
final ViewParent parent = getParent();
if (parent != null) {
parent.requestDisallowInterceptTouchEvent(true);
}
}
break;
}
case MotionEvent.ACTION_DOWN: {
final int x = (int) ev.getX();
final int y = (int) ev.getY();
if (!inChild(x, y)) {
mIsBeingDragged = false;
recycleVelocityTracker();
break;
}
/*
* Remember location of down touch.
* ACTION_DOWN always refers to pointer index 0.
*/
mLastMotionX = x;
mLastMotionY = y;
mActivePointerId = ev.getPointerId(0);
initOrResetVelocityTracker();
mVelocityTracker.addMovement(ev);
/*
* If being flinged and user touches the screen, initiate drag;
* otherwise don't. mScroller.isFinished should be false when
* being flinged.
*/
mIsBeingDragged = !mScroller.isFinished();
break;
}
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
/* Release the drag */
mIsBeingDragged = false;
mActivePointerId = INVALID_POINTER;
if (mScroller.springBack(getScrollX(), getScrollY(), 0, getHorizontalScrollRange(), 0, getVerticalScrollRange())) {
ViewCompat.postInvalidateOnAnimation(this);
}
break;
case MotionEvent.ACTION_POINTER_DOWN: {
final int index = ev.getActionIndex();
mLastMotionX = (int) ev.getX(index);
mLastMotionY = (int) ev.getY(index);
mActivePointerId = ev.getPointerId(index);
break;
}
case MotionEvent.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
final int index = ev.findPointerIndex(mActivePointerId);
mLastMotionX = (int) ev.getX(index);
mLastMotionY = (int) ev.getY(index);
break;
}
/*
* The only time we want to intercept motion events is if we are in the
* drag mode.
*/
return mIsBeingDragged;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
initVelocityTrackerIfNotExists();
mVelocityTracker.addMovement(ev);
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: {
if (getChildCount() == 0) {
return false;
}
if ((mIsBeingDragged = !mScroller.isFinished())) {
final ViewParent parent = getParent();
if (parent != null) {
parent.requestDisallowInterceptTouchEvent(true);
}
}
/*
* If being flinged and user touches, stop the fling. isFinished
* will be false if being flinged.
*/
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
// Remember where the motion event started
mLastMotionX = (int) ev.getX();
mLastMotionY = (int) ev.getY();
mActivePointerId = ev.getPointerId(0);
break;
}
case MotionEvent.ACTION_MOVE:
final int activePointerIndex = ev.findPointerIndex(mActivePointerId);
if (activePointerIndex == -1) {
Log.e(TAG, "Invalid pointerId=" + mActivePointerId + " in onTouchEvent");
break;
}
final int x = (int) ev.getX(activePointerIndex);
final int y = (int) ev.getY(activePointerIndex);
int deltaX = mLastMotionX - x;
int deltaY = mLastMotionY - y;
if (!mIsBeingDragged && (Math.abs(deltaX) > mTouchSlop || Math.abs(deltaY) > mTouchSlop)) {
final ViewParent parent = getParent();
if (parent != null) {
parent.requestDisallowInterceptTouchEvent(true);
}
mIsBeingDragged = true;
if (deltaX > 0) {
deltaX -= mTouchSlop;
deltaX = Math.max(0, deltaX);
} else {
deltaX += mTouchSlop;
deltaX = Math.min(0, deltaX);
}
if (deltaY > 0) {
deltaY -= mTouchSlop;
deltaY = Math.max(0, deltaY);
} else {
deltaY += mTouchSlop;
deltaY = Math.min(0, deltaY);
}
}
if (mIsBeingDragged) {
// Scroll to follow the motion event
mLastMotionX = x;
mLastMotionY = y;
final int oldX = getScrollX();
final int oldY = getScrollY();
final int horizontalRange = getHorizontalScrollRange();
final int verticalRange = getVerticalScrollRange();
final int overscrollMode = getOverScrollMode();
final boolean canOverscroll = overscrollMode == OVER_SCROLL_ALWAYS ||
(overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS &&
(horizontalRange > 0 || verticalRange > 0));
// Calling overScrollBy will call onOverScrolled, which
// calls onScrollChanged if applicable.
overScrollBy(deltaX, deltaY, oldX, oldY, horizontalRange, verticalRange,
mOverscrollDistance, mOverscrollDistance, true);
if (canOverscroll) {
final int pulledToX = oldX + deltaX;
final int pulledToY = oldY + deltaY;
if (pulledToX < 0) {
mEdgeGlowLeft.onPull((float) deltaX / getWidth());
if (!mEdgeGlowRight.isFinished()) {
mEdgeGlowRight.onRelease();
}
} else if (pulledToX > horizontalRange) {
mEdgeGlowRight.onPull((float) deltaX / getWidth());
if (!mEdgeGlowLeft.isFinished()) {
mEdgeGlowLeft.onRelease();
}
}
if (pulledToY < 0) {
mEdgeGlowTop.onPull((float) deltaY / getHeight());
if (!mEdgeGlowBottom.isFinished()) {
mEdgeGlowBottom.onRelease();
}
} else if (pulledToY > verticalRange) {
mEdgeGlowBottom.onPull((float) deltaY / getHeight());
if (!mEdgeGlowTop.isFinished()) {
mEdgeGlowTop.onRelease();
}
}
if (mEdgeGlowLeft != null
&& (!mEdgeGlowLeft.isFinished() || !mEdgeGlowRight.isFinished()
|| !mEdgeGlowTop.isFinished() || !mEdgeGlowBottom.isFinished())) {
ViewCompat.postInvalidateOnAnimation(this);
}
}
}
break;
case MotionEvent.ACTION_UP:
if (mIsBeingDragged) {
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
int initialVelocityX = (int) velocityTracker.getXVelocity(mActivePointerId);
int initialVelocityY = (int) velocityTracker.getYVelocity(mActivePointerId);
if (getChildCount() > 0) {
if (Math.abs(initialVelocityX) > mMinimumVelocity || Math.abs(initialVelocityY) > mMinimumVelocity) {
fling(-initialVelocityX, -initialVelocityY);
} else {
if (mScroller.springBack(getScrollX(), getScrollY(), 0,
getHorizontalScrollRange(), 0, getVerticalScrollRange())) {
ViewCompat.postInvalidateOnAnimation(this);
}
}
}
mActivePointerId = INVALID_POINTER;
endDrag();
}
break;
case MotionEvent.ACTION_CANCEL:
if (mIsBeingDragged && getChildCount() > 0) {
if (mScroller.springBack(getScrollX(), getScrollY(), 0,
getHorizontalScrollRange(), 0, getVerticalScrollRange())) {
ViewCompat.postInvalidateOnAnimation(this);
}
mActivePointerId = INVALID_POINTER;
endDrag();
}
break;
case MotionEvent.ACTION_POINTER_DOWN: {
final int index = ev.getActionIndex();
mLastMotionX = (int) ev.getX(index);
mLastMotionY = (int) ev.getY(index);
mActivePointerId = ev.getPointerId(index);
break;
}
case MotionEvent.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
final int index = ev.findPointerIndex(mActivePointerId);
mLastMotionX = (int) ev.getX(index);
mLastMotionY = (int) ev.getY(index);
break;
}
return true;
}
private void onSecondaryPointerUp(MotionEvent ev) {
final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >>
MotionEvent.ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId) {
// This was our active pointer going up. Choose a new
// active pointer and adjust accordingly.
// TODO: Make this decision more intelligent.
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mLastMotionX = (int) ev.getY(newPointerIndex);
mLastMotionY = (int) ev.getY(newPointerIndex);
mActivePointerId = ev.getPointerId(newPointerIndex);
if (mVelocityTracker != null) {
mVelocityTracker.clear();
}
}
}
/**
* Gets a scale factor that determines the distance the view should scroll
* vertically in response to {@link MotionEvent#ACTION_SCROLL}.
* @return The vertical scroll scale factor.
*/
protected float getVerticalScrollFactor() {
if (mVerticalScrollFactor == 0) {
Context context = getContext();
TypedValue outValue = new TypedValue();
if (!context.getTheme().resolveAttribute(16842829, outValue, true)) { // listPreferredItemHeight
throw new IllegalStateException(
"Expected theme to define listPreferredItemHeight.");
}
mVerticalScrollFactor = outValue.getDimension(
context.getResources().getDisplayMetrics());
}
return mVerticalScrollFactor;
}
/**
* Gets a scale factor that determines the distance the view should scroll
* horizontally in response to {@link MotionEvent#ACTION_SCROLL}.
* @return The horizontal scroll scale factor.
*/
protected float getHorizontalScrollFactor() {
// TODO: Should use something else.
return getVerticalScrollFactor();
}
@Override
public boolean onGenericMotionEvent(MotionEvent event) {
if ((event.getSource() & InputDevice.SOURCE_CLASS_POINTER) != 0) {
switch (event.getAction()) {
case MotionEvent.ACTION_SCROLL: {
if (!mIsBeingDragged) {
if ((event.getMetaState() & KeyEvent.META_SHIFT_ON) != 0) {
final float hscroll = event.getAxisValue(MotionEvent.AXIS_VSCROLL);
if (hscroll != 0) {
final int delta = (int) (hscroll * getHorizontalScrollFactor());
final int range = getHorizontalScrollRange();
int oldScrollX = getScrollX();
int newScrollX = oldScrollX + delta;
if (newScrollX < 0) {
newScrollX = 0;
} else if (newScrollX > range) {
newScrollX = range;
}
if (newScrollX != oldScrollX) {
super.scrollTo(newScrollX, getScrollY());
return true;
}
}
} else {
final float vscroll = event.getAxisValue(MotionEvent.AXIS_VSCROLL);
if (vscroll != 0) {
final int delta = (int) (vscroll * getVerticalScrollFactor());
final int range = getVerticalScrollRange();
int oldScrollY = getScrollY();
int newScrollY = oldScrollY - delta;
if (newScrollY < 0) {
newScrollY = 0;
} else if (newScrollY > range) {
newScrollY = range;
}
if (newScrollY != oldScrollY) {
super.scrollTo(getScrollX(), newScrollY);
return true;
}
}
}
}
}
}
}
return super.onGenericMotionEvent(event);
}
@Override
public boolean shouldDelayChildPressedState() {
return true;
}
@Override
protected void onOverScrolled(int scrollX, int scrollY,
boolean clampedX, boolean clampedY) {
if (clampedX && clampedY && mVelocityTracker != null) {
mVelocityTracker.clear();
}
// Treat animating scrolls differently; see #computeScroll() for why.
if (!mScroller.isFinished()) {
setScrollX(scrollX);
setScrollY(scrollY);
if (clampedX) {
mScroller.springBackX(scrollX, 0, getHorizontalScrollRange());
}
if (clampedY) {
mScroller.springBackY(scrollY, 0, getVerticalScrollRange());
}
} else {
super.scrollTo(scrollX, scrollY);
}
awakenScrollBars();
}
@Override
public CharSequence getAccessibilityClassName() {
return ScrollView.class.getName();
}
private int getHorizontalScrollRange() {
int scrollRange = 0;
if (getChildCount() > 0) {
View child = getChildAt(0);
scrollRange = Math.max(0,
child.getWidth() - (getWidth() - getPaddingLeft() - getPaddingRight()));
}
return scrollRange;
}
private int getVerticalScrollRange() {
int scrollRange = 0;
if (getChildCount() > 0) {
View child = getChildAt(0);
scrollRange = Math.max(0,
child.getHeight() - (getHeight() - getPaddingTop() - getPaddingBottom()));
}
return scrollRange;
}
/**
* <p>
* Finds the next focusable component that fits in this View's bounds
* (excluding fading edges) pretending that this View's left is located at
* the parameter left.
* </p>
*
* @param leftFocus look for a candidate is the one at the left of the bounds
* if leftFocus is true, or at the right of the bounds if leftFocus
* is false
* @param left the left offset of the bounds in which a focusable must be
* found (the fading edge is assumed to start at this position)
* @param preferredFocusable the View that has highest priority and will be
* returned if it is within my bounds (null is valid)
* @return the next focusable component in the bounds or null if none can be found
*/
private View findFocusableViewInMyBoundsHorizontally(final boolean leftFocus,
final int left, View preferredFocusable) {
/*
* The fading edge's transparent side should be considered for focus
* since it's mostly visible, so we divide the actual fading edge length
* by 2.
*/
final int fadingEdgeLength = getHorizontalFadingEdgeLength() / 2;
final int leftWithoutFadingEdge = left + fadingEdgeLength;
final int rightWithoutFadingEdge = left + getWidth() - fadingEdgeLength;
if ((preferredFocusable != null)
&& (preferredFocusable.getLeft() < rightWithoutFadingEdge)
&& (preferredFocusable.getRight() > leftWithoutFadingEdge)) {
return preferredFocusable;
}
return findFocusableViewInBoundsHorizontally(leftFocus, leftWithoutFadingEdge,
rightWithoutFadingEdge);
}
/**
* <p>
* Finds the next focusable component that fits in the specified bounds.
* </p>
*
* @param leftFocus look for a candidate is the one at the left of the bounds
* if leftFocus is true, or at the right of the bounds if
* leftFocus is false
* @param left the left offset of the bounds in which a focusable must be
* found
* @param right the right offset of the bounds in which a focusable must
* be found
* @return the next focusable component in the bounds or null if none can
* be found
*/
private View findFocusableViewInBoundsHorizontally(boolean leftFocus, int left, int right) {
List<View> focusables = getFocusables(View.FOCUS_FORWARD);
View focusCandidate = null;
/*
* A fully contained focusable is one where its left is below the bound's
* left, and its right is above the bound's right. A partially
* contained focusable is one where some part of it is within the
* bounds, but it also has some part that is not within bounds. A fully contained
* focusable is preferred to a partially contained focusable.
*/
boolean foundFullyContainedFocusable = false;
int count = focusables.size();
for (int i = 0; i < count; i++) {
View view = focusables.get(i);
int viewLeft = view.getLeft();
int viewRight = view.getRight();
if (left < viewRight && viewLeft < right) {
/*
* the focusable is in the target area, it is a candidate for
* focusing
*/
final boolean viewIsFullyContained = (left < viewLeft) &&
(viewRight < right);
if (focusCandidate == null) {
/* No candidate, take this one */
focusCandidate = view;
foundFullyContainedFocusable = viewIsFullyContained;
} else {
final boolean viewIsCloserToBoundary =
(leftFocus && viewLeft < focusCandidate.getLeft()) ||
(!leftFocus && viewRight > focusCandidate.getRight());
if (foundFullyContainedFocusable) {
if (viewIsFullyContained && viewIsCloserToBoundary) {
/*
* We're dealing with only fully contained views, so
* it has to be closer to the boundary to beat our
* candidate
*/
focusCandidate = view;
}
} else {
if (viewIsFullyContained) {
/* Any fully contained view beats a partially contained view */
focusCandidate = view;
foundFullyContainedFocusable = true;
} else if (viewIsCloserToBoundary) {
/*
* Partially contained view beats another partially
* contained view if it's closer
*/
focusCandidate = view;
}
}
}
}
}
return focusCandidate;
}
/**
* <p>
* Finds the next focusable component that fits in the specified bounds.
* </p>
*
* @param topFocus look for a candidate is the one at the top of the bounds
* if topFocus is true, or at the bottom of the bounds if topFocus is
* false
* @param top the top offset of the bounds in which a focusable must be
* found
* @param bottom the bottom offset of the bounds in which a focusable must
* be found
* @return the next focusable component in the bounds or null if none can
* be found
*/
private View findFocusableViewInBoundsVertically(boolean topFocus, int top, int bottom) {
List<View> focusables = getFocusables(View.FOCUS_FORWARD);
View focusCandidate = null;
/*
* A fully contained focusable is one where its top is below the bound's
* top, and its bottom is above the bound's bottom. A partially
* contained focusable is one where some part of it is within the
* bounds, but it also has some part that is not within bounds. A fully contained
* focusable is preferred to a partially contained focusable.
*/
boolean foundFullyContainedFocusable = false;
int count = focusables.size();
for (int i = 0; i < count; i++) {
View view = focusables.get(i);
int viewTop = view.getTop();
int viewBottom = view.getBottom();
if (top < viewBottom && viewTop < bottom) {
/*
* the focusable is in the target area, it is a candidate for
* focusing
*/
final boolean viewIsFullyContained = (top < viewTop) &&
(viewBottom < bottom);
if (focusCandidate == null) {
/* No candidate, take this one */
focusCandidate = view;
foundFullyContainedFocusable = viewIsFullyContained;
} else {
final boolean viewIsCloserToBoundary =
(topFocus && viewTop < focusCandidate.getTop()) ||
(!topFocus && viewBottom > focusCandidate
.getBottom());
if (foundFullyContainedFocusable) {
if (viewIsFullyContained && viewIsCloserToBoundary) {
/*
* We're dealing with only fully contained views, so
* it has to be closer to the boundary to beat our
* candidate
*/
focusCandidate = view;
}
} else {
if (viewIsFullyContained) {
/* Any fully contained view beats a partially contained view */
focusCandidate = view;
foundFullyContainedFocusable = true;
} else if (viewIsCloserToBoundary) {
/*
* Partially contained view beats another partially
* contained view if it's closer
*/
focusCandidate = view;
}
}
}
}
}
return focusCandidate;
}
/**
* <p>Handles scrolling in response to a "page up/down" shortcut press. This
* method will scroll the view by one page left or right and give the focus
* to the leftmost/rightmost component in the new visible area. If no
* component is a good candidate for focus, this scrollview reclaims the
* focus.</p>
*
* @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT}
* to go one page left or {@link android.view.View#FOCUS_RIGHT}
* to go one page right
* @return true if the key event is consumed by this method, false otherwise
*/
public boolean pageScroll(int direction) {
int width = getWidth();
int height = getHeight();
if (direction == View.FOCUS_UP) {
mTempRect.top = getScrollY() - height;
if (mTempRect.top < 0) {
mTempRect.top = 0;
}
mTempRect.bottom = mTempRect.top + height;
return scrollAndFocusVertically(direction, mTempRect.top, mTempRect.bottom);
} else if (direction == View.FOCUS_DOWN) {
mTempRect.top = getScrollY() + height;
int count = getChildCount();
if (count > 0) {
View view = getChildAt(count - 1);
if (mTempRect.top + height > view.getBottom()) {
mTempRect.top = view.getBottom() - height;
}
}
mTempRect.bottom = mTempRect.top + height;
return scrollAndFocusVertically(direction, mTempRect.top, mTempRect.bottom);
} else if (direction == View.FOCUS_LEFT) {
mTempRect.left = getScrollX() - width;
if (mTempRect.left < 0) {
mTempRect.left = 0;
}
mTempRect.right = mTempRect.left + width;
return scrollAndFocusHorizontally(direction, mTempRect.left, mTempRect.right);
} else {
mTempRect.left = getScrollX() + width;
int count = getChildCount();
if (count > 0) {
View view = getChildAt(0);
if (mTempRect.left + width > view.getRight()) {
mTempRect.left = view.getRight() - width;
}
}
mTempRect.right = mTempRect.left + width;
return scrollAndFocusHorizontally(direction, mTempRect.left, mTempRect.right);
}
}
/**
* <p>Handles scrolling in response to a "home/end" shortcut press. This
* method will scroll the view to the left or right and give the focus
* to the leftmost/rightmost component in the new visible area. If no
* component is a good candidate for focus, this scrollview reclaims the
* focus.</p>
*
* @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT}
* to go the left of the view or {@link android.view.View#FOCUS_RIGHT}
* to go the right
* @return true if the key event is consumed by this method, false otherwise
*/
public boolean fullScroll(int direction) {
if (direction == View.FOCUS_LEFT || direction == View.FOCUS_RIGHT) {
boolean right = direction == View.FOCUS_RIGHT;
int width = getWidth();
mTempRect.left = 0;
mTempRect.right = width;
if (right) {
int count = getChildCount();
if (count > 0) {
View view = getChildAt(0);
mTempRect.right = view.getRight() + getPaddingRight();
mTempRect.left = mTempRect.right - width;
}
}
return scrollAndFocusHorizontally(direction, mTempRect.left, mTempRect.right);
} else {
boolean down = direction == View.FOCUS_DOWN;
int height = getHeight();
mTempRect.top = 0;
mTempRect.bottom = height;
if (down) {
int count = getChildCount();
if (count > 0) {
View view = getChildAt(count - 1);
mTempRect.bottom = view.getBottom() + getPaddingBottom();
mTempRect.top = mTempRect.bottom - height;
}
}
return scrollAndFocusVertically(direction, mTempRect.top, mTempRect.bottom);
}
}
/**
* <p>Scrolls the view to make the area defined by <code>left</code> and
* <code>right</code> visible. This method attempts to give the focus
* to a component visible in this area. If no component can be focused in
* the new visible area, the focus is reclaimed by this scrollview.</p>
*
* @param direction the scroll direction: {@link android.view.View#FOCUS_LEFT}
* to go left {@link android.view.View#FOCUS_RIGHT} to right
* @param left the left offset of the new area to be made visible
* @param right the right offset of the new area to be made visible
* @return true if the key event is consumed by this method, false otherwise
*/
private boolean scrollAndFocusHorizontally(int direction, int left, int right) {
boolean handled = true;
int width = getWidth();
int containerLeft = getScrollX();
int containerRight = containerLeft + width;
boolean goLeft = direction == View.FOCUS_LEFT;
View newFocused = findFocusableViewInBoundsHorizontally(goLeft, left, right);
if (newFocused == null) {
newFocused = this;
}
if (left >= containerLeft && right <= containerRight) {
handled = false;
} else {
int delta = goLeft ? (left - containerLeft) : (right - containerRight);
doScrollX(delta);
}
if (newFocused != findFocus()) newFocused.requestFocus(direction);
return handled;
}
/**
* <p>Scrolls the view to make the area defined by <code>top</code> and
* <code>bottom</code> visible. This method attempts to give the focus
* to a component visible in this area. If no component can be focused in
* the new visible area, the focus is reclaimed by this ScrollView.</p>
*
* @param direction the scroll direction: {@link android.view.View#FOCUS_UP}
* to go upward, {@link android.view.View#FOCUS_DOWN} to downward
* @param top the top offset of the new area to be made visible
* @param bottom the bottom offset of the new area to be made visible
* @return true if the key event is consumed by this method, false otherwise
*/
private boolean scrollAndFocusVertically(int direction, int top, int bottom) {
boolean handled = true;
int height = getHeight();
int containerTop = getScrollY();
int containerBottom = containerTop + height;
boolean up = direction == View.FOCUS_UP;
View newFocused = findFocusableViewInBoundsVertically(up, top, bottom);
if (newFocused == null) {
newFocused = this;
}
if (top >= containerTop && bottom <= containerBottom) {
handled = false;
} else {
int delta = up ? (top - containerTop) : (bottom - containerBottom);
doScrollY(delta);
}
if (newFocused != findFocus()) newFocused.requestFocus(direction);
return handled;
}
/**
* Handle scrolling in response to a left or right arrow click.
*
* @param direction The direction corresponding to the arrow key that was
* pressed
* @return True if we consumed the event, false otherwise
*/
public boolean arrowScrollHorizontally(int direction) {
View currentFocused = findFocus();
if (currentFocused == this) currentFocused = null;
View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, direction);
final int maxJump = getHorizontalMaxScrollAmount();
if (nextFocused != null && isWithinDeltaOfScreen(nextFocused, maxJump, getWidth(), getHeight())) {
nextFocused.getDrawingRect(mTempRect);
offsetDescendantRectToMyCoords(nextFocused, mTempRect);
int scrollDelta = computeScrollXDeltaToGetChildRectOnScreen(mTempRect);
doScrollX(scrollDelta);
nextFocused.requestFocus(direction);
} else {
// no new focus
int scrollDelta = maxJump;
if (direction == View.FOCUS_LEFT && getScrollX() < scrollDelta) {
scrollDelta = getScrollX();
} else if (direction == View.FOCUS_RIGHT && getChildCount() > 0) {
int daRight = getChildAt(0).getRight();
int screenRight = getScrollX() + getWidth() - getPaddingRight();
if (daRight - screenRight < maxJump) {
scrollDelta = daRight - screenRight;
}
}
if (scrollDelta == 0) {
return false;
}
doScrollX(direction == View.FOCUS_RIGHT ? scrollDelta : -scrollDelta);
}
if (currentFocused != null && currentFocused.isFocused()
&& isOffScreen(currentFocused)) {
// previously focused item still has focus and is off screen, give
// it up (take it back to ourselves)
// (also, need to temporarily force FOCUS_BEFORE_DESCENDANTS so we are
// sure to
// get it)
final int descendantFocusability = getDescendantFocusability(); // save
setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS);
requestFocus();
setDescendantFocusability(descendantFocusability); // restore
}
return true;
}
/**
* Handle scrolling in response to an up or down arrow click.
*
* @param direction The direction corresponding to the arrow key that was
* pressed
* @return True if we consumed the event, false otherwise
*/
public boolean arrowScrollVertically(int direction) {
View currentFocused = findFocus();
if (currentFocused == this) currentFocused = null;
View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, direction);
final int maxJump = getVerticalMaxScrollAmount();
if (nextFocused != null && isWithinDeltaOfScreen(nextFocused, maxJump, getWidth(), getHeight())) {
nextFocused.getDrawingRect(mTempRect);
offsetDescendantRectToMyCoords(nextFocused, mTempRect);
int scrollDelta = computeScrollYDeltaToGetChildRectOnScreen(mTempRect);
doScrollY(scrollDelta);
nextFocused.requestFocus(direction);
} else {
// no new focus
int scrollDelta = maxJump;
if (direction == View.FOCUS_UP && getScrollY() < scrollDelta) {
scrollDelta = getScrollY();
} else if (direction == View.FOCUS_DOWN) {
if (getChildCount() > 0) {
int daBottom = getChildAt(0).getBottom();
int screenBottom = getScrollY() + getHeight() - getPaddingBottom();
if (daBottom - screenBottom < maxJump) {
scrollDelta = daBottom - screenBottom;
}
}
}
if (scrollDelta == 0) {
return false;
}
doScrollY(direction == View.FOCUS_DOWN ? scrollDelta : -scrollDelta);
}
if (currentFocused != null && currentFocused.isFocused()
&& isOffScreen(currentFocused)) {
// previously focused item still has focus and is off screen, give
// it up (take it back to ourselves)
// (also, need to temporarily force FOCUS_BEFORE_DESCENDANTS so we are
// sure to
// get it)
final int descendantFocusability = getDescendantFocusability(); // save
setDescendantFocusability(ViewGroup.FOCUS_BEFORE_DESCENDANTS);
requestFocus();
setDescendantFocusability(descendantFocusability); // restore
}
return true;
}
/**
* @return whether the descendant of this scroll view is scrolled off
* screen.
*/
private boolean isOffScreen(View descendant) {
return !isWithinDeltaOfScreen(descendant, 0, getWidth(), getHeight());
}
/**
* @return whether the descendant of this scroll view is within delta
* pixels of being on the screen.
*/
private boolean isWithinDeltaOfScreen(View descendant, int delta, int width, int height) {
descendant.getDrawingRect(mTempRect);
offsetDescendantRectToMyCoords(descendant, mTempRect);
return (mTempRect.right + delta) >= getScrollX()
&& (mTempRect.left - delta) <= (getScrollX() + width)
&& (mTempRect.bottom + delta) >= getScrollY()
&& (mTempRect.top - delta) <= (getScrollY() + height);
}
/**
* Smooth scroll by a X delta
*
* @param delta the number of pixels to scroll by on the X axis
*/
private void doScrollX(int delta) {
if (delta != 0) {
if (mSmoothScrollingEnabled) {
smoothScrollBy(delta, 0);
} else {
scrollBy(delta, 0);
}
}
}
/**
* Smooth scroll by a Y delta
*
* @param delta the number of pixels to scroll by on the Y axis
*/
private void doScrollY(int delta) {
if (delta != 0) {
if (mSmoothScrollingEnabled) {
smoothScrollBy(0, delta);
} else {
scrollBy(0, delta);
}
}
}
/**
* Like {@link View#scrollBy}, but scroll smoothly instead of immediately.
*
* @param dx the number of pixels to scroll by on the X axis
* @param dy the number of pixels to scroll by on the Y axis
*/
public final void smoothScrollBy(int dx, int dy) {
if (getChildCount() == 0) {
// Nothing to do.
return;
}
long duration = AnimationUtils.currentAnimationTimeMillis() - mLastScroll;
if (duration > ANIMATED_SCROLL_GAP) {
final int width = getWidth() - getPaddingRight() - getPaddingLeft();
final int height = getHeight() - getPaddingBottom() - getPaddingTop();
final int right = getChildAt(0).getWidth();
final int bottom = getChildAt(0).getHeight();
final int maxX = Math.max(0, right - width);
final int maxY = Math.max(0, bottom - height);
final int scrollX = getScrollX();
final int scrollY = getScrollY();
dx = Math.max(0, Math.min(scrollX + dx, maxX)) - scrollX;
dy = Math.max(0, Math.min(scrollY + dy, maxY)) - scrollY;
mScroller.startScroll(scrollX, scrollY, dx, dy);
ViewCompat.postInvalidateOnAnimation(this);
} else {
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
scrollBy(dx, dy);
}
mLastScroll = AnimationUtils.currentAnimationTimeMillis();
}
/**
* Like {@link #scrollTo}, but scroll smoothly instead of immediately.
*
* @param x the position where to scroll on the X axis
* @param y the position where to scroll on the Y axis
*/
public final void smoothScrollTo(int x, int y) {
smoothScrollBy(x - getScrollX(), y - getScrollY());
}
/**
* <p>The scroll range of a scroll view is the overall width of all of its
* children.</p>
*/
@Override
protected int computeHorizontalScrollRange() {
final int count = getChildCount();
final int contentWidth = getWidth() - getPaddingLeft() - getPaddingRight();
if (count == 0) {
return contentWidth;
}
int scrollRange = getChildAt(0).getRight();
final int scrollX = getScrollX();
final int overscrollRight = Math.max(0, scrollRange - contentWidth);
if (scrollX < 0) {
scrollRange -= scrollX;
} else if (scrollX > overscrollRight) {
scrollRange += scrollX - overscrollRight;
}
return scrollRange;
}
/**
* <p>The scroll range of a scroll view is the overall height of all of its
* children.</p>
*/
@Override
protected int computeVerticalScrollRange() {
final int count = getChildCount();
final int contentHeight = getHeight() - getPaddingTop() - getPaddingBottom();
if (count == 0) {
return contentHeight;
}
int scrollRange = getChildAt(0).getBottom();
final int scrollY = getScrollY();
final int overscrollBottom = Math.max(0, scrollRange - contentHeight);
if (scrollY < 0) {
scrollRange -= scrollY;
} else if (scrollY > overscrollBottom) {
scrollRange += scrollY - overscrollBottom;
}
return scrollRange;
}
@Override
protected void measureChild(View child, int parentWidthMeasureSpec, int parentHeightMeasureSpec) {
ViewGroup.LayoutParams lp = child.getLayoutParams();
int childWidthMeasureSpec;
int childHeightMeasureSpec;
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}
@Override
protected void measureChildWithMargins(View child, int parentWidthMeasureSpec, int widthUsed,
int parentHeightMeasureSpec, int heightUsed) {
final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();
final int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
lp.topMargin + lp.bottomMargin, MeasureSpec.UNSPECIFIED);
final int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(
lp.leftMargin + lp.rightMargin, MeasureSpec.UNSPECIFIED);
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}
@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
// This is called at drawing time by ViewGroup. We don't want to
// re-show the scrollbars at this point, which scrollTo will do,
// so we replicate most of scrollTo here.
//
// It's a little odd to call onScrollChanged from inside the drawing.
//
// It is, except when you remember that computeScroll() is used to
// animate scrolling. So unless we want to defer the onScrollChanged()
// until the end of the animated scrolling, we don't really have a
// choice here.
//
// I agree. The alternative, which I think would be worse, is to post
// something and tell the subclasses later. This is bad because there
// will be a window where mScrollX/Y is different from what the app
// thinks it is.
//
int oldX = getScrollX();
int oldY = getScrollY();
int x = mScroller.getCurrX();
int y = mScroller.getCurrY();
if (oldX != x || oldY != y) {
final int horizontalRange = getHorizontalScrollRange();
final int verticalRange = getVerticalScrollRange();
final int overscrollMode = getOverScrollMode();
final boolean canOverscroll = overscrollMode == OVER_SCROLL_ALWAYS ||
(overscrollMode == OVER_SCROLL_IF_CONTENT_SCROLLS
&& (horizontalRange > 0 || verticalRange > 0));
overScrollBy(x - oldX, y - oldY, oldX, oldY, horizontalRange, verticalRange,
mOverflingDistance, 0, false);
onScrollChanged(getScrollX(), getScrollY(), oldX, oldY);
if (canOverscroll) {
if (x < 0 && oldX >= 0) {
mEdgeGlowLeft.onAbsorb((int) mScroller.getCurrVelocity());
} else if (x > horizontalRange && oldX <= horizontalRange) {
mEdgeGlowRight.onAbsorb((int) mScroller.getCurrVelocity());
}
if (y < 0 && oldY >= 0) {
mEdgeGlowTop.onAbsorb((int) mScroller.getCurrVelocity());
} else if (y > verticalRange && oldY <= verticalRange) {
mEdgeGlowBottom.onAbsorb((int) mScroller.getCurrVelocity());
}
}
}
if (!awakenScrollBars()) {
ViewCompat.postInvalidateOnAnimation(this);
}
}
}
/**
* Scrolls the view to the given child.
*
* @param child the View to scroll to
*/
private void scrollToChild(View child) {
child.getDrawingRect(mTempRect);
/* Offset from child's local coordinates to ScrollView coordinates */
offsetDescendantRectToMyCoords(child, mTempRect);
int scrollXDelta = computeScrollXDeltaToGetChildRectOnScreen(mTempRect);
int scrollYDelta = computeScrollYDeltaToGetChildRectOnScreen(mTempRect);
if (scrollXDelta != 0 && scrollYDelta != 0) {
scrollBy(scrollXDelta, scrollYDelta);
}
}
/**
* If rect is off screen, scroll just enough to get it (or at least the
* first screen size chunk of it) on screen.
*
* @param rect The rectangle.
* @param immediate True to scroll immediately without animation
* @return true if scrolling was performed
*/
private boolean scrollToChildRect(Rect rect, boolean immediate) {
final int deltaX = computeScrollXDeltaToGetChildRectOnScreen(rect);
final int deltaY = computeScrollYDeltaToGetChildRectOnScreen(rect);
final boolean scroll = deltaX != 0 && deltaY != 0;
if (scroll) {
if (immediate) {
scrollBy(deltaX, deltaY);
} else {
smoothScrollBy(deltaX, deltaY);
}
}
return scroll;
}
/**
* Compute the amount to scroll in the X direction in order to get
* a rectangle completely on the screen (or, if taller than the screen,
* at least the first screen size chunk of it).
*
* @param rect The rect.
* @return The scroll delta.
*/
protected int computeScrollXDeltaToGetChildRectOnScreen(Rect rect) {
if (getChildCount() == 0) return 0;
int width = getWidth();
int screenLeft = getScrollX();
int screenRight = screenLeft + width;
int fadingEdge = getHorizontalFadingEdgeLength();
// leave room for left fading edge as long as rect isn't at very left
if (rect.left > 0) {
screenLeft += fadingEdge;
}
// leave room for right fading edge as long as rect isn't at very right
if (rect.right < getChildAt(0).getWidth()) {
screenRight -= fadingEdge;
}
int scrollXDelta = 0;
if (rect.right > screenRight && rect.left > screenLeft) {
// need to move right to get it in view: move right just enough so
// that the entire rectangle is in view (or at least the first
// screen size chunk).
if (rect.width() > width) {
// just enough to get screen size chunk on
scrollXDelta += (rect.left - screenLeft);
} else {
// get entire rect at right of screen
scrollXDelta += (rect.right - screenRight);
}
// make sure we aren't scrolling beyond the end of our content
int right = getChildAt(0).getRight();
int distanceToRight = right - screenRight;
scrollXDelta = Math.min(scrollXDelta, distanceToRight);
} else if (rect.left < screenLeft && rect.right < screenRight) {
// need to move right to get it in view: move right just enough so that
// entire rectangle is in view (or at least the first screen
// size chunk of it).
if (rect.width() > width) {
// screen size chunk
scrollXDelta -= (screenRight - rect.right);
} else {
// entire rect at left
scrollXDelta -= (screenLeft - rect.left);
}
// make sure we aren't scrolling any further than the left our content
scrollXDelta = Math.max(scrollXDelta, -getScrollX());
}
return scrollXDelta;
}
/**
* Compute the amount to scroll in the Y direction in order to get
* a rectangle completely on the screen (or, if taller than the screen,
* at least the first screen size chunk of it).
*
* @param rect The rect.
* @return The scroll delta.
*/
protected int computeScrollYDeltaToGetChildRectOnScreen(Rect rect) {
if (getChildCount() == 0) return 0;
int height = getHeight();
int screenTop = getScrollY();
int screenBottom = screenTop + height;
int fadingEdge = getVerticalFadingEdgeLength();
// leave room for top fading edge as long as rect isn't at very top
if (rect.top > 0) {
screenTop += fadingEdge;
}
// leave room for bottom fading edge as long as rect isn't at very bottom
if (rect.bottom < getChildAt(0).getHeight()) {
screenBottom -= fadingEdge;
}
int scrollYDelta = 0;
if (rect.bottom > screenBottom && rect.top > screenTop) {
// need to move down to get it in view: move down just enough so
// that the entire rectangle is in view (or at least the first
// screen size chunk).
if (rect.height() > height) {
// just enough to get screen size chunk on
scrollYDelta += (rect.top - screenTop);
} else {
// get entire rect at bottom of screen
scrollYDelta += (rect.bottom - screenBottom);
}
// make sure we aren't scrolling beyond the end of our content
int bottom = getChildAt(0).getBottom();
int distanceToBottom = bottom - screenBottom;
scrollYDelta = Math.min(scrollYDelta, distanceToBottom);
} else if (rect.top < screenTop && rect.bottom < screenBottom) {
// need to move up to get it in view: move up just enough so that
// entire rectangle is in view (or at least the first screen
// size chunk of it).
if (rect.height() > height) {
// screen size chunk
scrollYDelta -= (screenBottom - rect.bottom);
} else {
// entire rect at top
scrollYDelta -= (screenTop - rect.top);
}
// make sure we aren't scrolling any further than the top our content
scrollYDelta = Math.max(scrollYDelta, -getScrollY());
}
return scrollYDelta;
}
@Override
public void requestChildFocus(View child, View focused) {
if (!mIsLayoutDirty) {
scrollToChild(focused);
} else {
// The child may not be laid out yet, we can't compute the scroll yet
mChildToScrollTo = focused;
}
super.requestChildFocus(child, focused);
}
/**
* When looking for focus in children of a scroll view, need to be a little
* more careful not to give focus to something that is scrolled off screen.
*
* This is more expensive than the default {@link android.view.ViewGroup}
* implementation, otherwise this behavior might have been made the default.
*/
@Override
protected boolean onRequestFocusInDescendants(int direction,
Rect previouslyFocusedRect) {
// convert from forward / backward notation to up / down / left / right
// (ugh).
if (direction == View.FOCUS_FORWARD) {
direction = View.FOCUS_RIGHT;
} else if (direction == View.FOCUS_BACKWARD) {
direction = View.FOCUS_LEFT;
}
final View nextFocus = previouslyFocusedRect == null ?
FocusFinder.getInstance().findNextFocus(this, null, direction) :
FocusFinder.getInstance().findNextFocusFromRect(this,
previouslyFocusedRect, direction);
if (nextFocus == null) {
return false;
}
if (isOffScreen(nextFocus)) {
return false;
}
return nextFocus.requestFocus(direction, previouslyFocusedRect);
}
@Override
public boolean requestChildRectangleOnScreen(View child, Rect rectangle,
boolean immediate) {
// offset into coordinate space of this scroll view
rectangle.offset(child.getLeft() - child.getScrollX(),
child.getTop() - child.getScrollY());
return scrollToChildRect(rectangle, immediate);
}
@Override
public void requestLayout() {
mIsLayoutDirty = true;
super.requestLayout();
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
mLaidOut = false;
}
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
mLaidOut = false;
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
mIsLayoutDirty = false;
// Give a child focus if it needs it
if (mChildToScrollTo != null && isViewDescendantOf(mChildToScrollTo, this)) {
scrollToChild(mChildToScrollTo);
}
mChildToScrollTo = null;
if (!mLaidOut) {
int scrollX = 0;
int scrollY = 0;
if (mSavedState != null) {
scrollX = mSavedState.getInt(KEY_SCROLL_X, 0);
scrollY = mSavedState.getInt(KEY_SCROLL_Y, 0);
mSavedState = null;
} // scrollX and scrollY default value is "0"
final int childWidth = (getChildCount() > 0) ? getChildAt(0).getMeasuredWidth() : 0;
final int childHeight = (getChildCount() > 0) ? getChildAt(0).getMeasuredHeight() : 0;
final int scrollRangeX = Math.max(0,
childWidth - (r - l - getPaddingLeft() - getPaddingRight()));
final int scrollRangeY = Math.max(0,
childHeight - (b - t - getPaddingTop() - getPaddingBottom()));
// Don't forget to clamp
if (scrollX > scrollRangeX) {
scrollX = scrollRangeX;
} else if (scrollX < 0) {
scrollX = 0;
}
if (scrollY > scrollRangeY) {
scrollY = scrollRangeY;
} else if (scrollX < 0) {
scrollY = 0;
}
// Calling this with the present values causes it to re-claim them
scrollTo(scrollX, scrollY);
}
mLaidOut = true;
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
View currentFocused = findFocus();
if (null == currentFocused || this == currentFocused)
return;
final int maxJump = getRight() - getLeft();
if (isWithinDeltaOfScreen(currentFocused, maxJump, w, h)) {
currentFocused.getDrawingRect(mTempRect);
offsetDescendantRectToMyCoords(currentFocused, mTempRect);
int scrollXDelta = computeScrollXDeltaToGetChildRectOnScreen(mTempRect);
int scrollYDelta = computeScrollYDeltaToGetChildRectOnScreen(mTempRect);
doScrollX(scrollXDelta);
doScrollY(scrollYDelta);
}
}
/**
* Return true if child is a descendant of parent, (or equal to the parent).
*/
private static boolean isViewDescendantOf(View child, View parent) {
if (child == parent) {
return true;
}
final ViewParent theParent = child.getParent();
return (theParent instanceof ViewGroup) && isViewDescendantOf((View) theParent, parent);
}
/**
* Fling the scroll view
*
* @param velocityX The initial velocity in the X direction. Positive
* numbers mean that the finger/cursor is moving down the screen,
* which means we want to scroll towards the left.
* @param velocityY The initial velocity in the Y direction. Positive
* numbers mean that the finger/cursor is moving down the screen,
* which means we want to scroll towards the top.
*/
public void fling(int velocityX, int velocityY) {
if (getChildCount() > 0) {
int width = getWidth() - getPaddingLeft() - getPaddingRight();
int height = getHeight() - getPaddingTop() - getPaddingBottom();
int right = getChildAt(0).getWidth();
int bottom = getChildAt(0).getHeight();
mScroller.fling(getScrollX(), getScrollY(), velocityX, velocityY,
0, Math.max(0, right - width), 0, Math.max(0, bottom - height),
width / 2, height / 2);
ViewCompat.postInvalidateOnAnimation(this);
}
}
private void endDrag() {
mIsBeingDragged = false;
recycleVelocityTracker();
if (mEdgeGlowLeft != null) {
mEdgeGlowLeft.onRelease();
mEdgeGlowRight.onRelease();
mEdgeGlowTop.onRelease();
mEdgeGlowBottom.onRelease();
}
}
/**
* {@inheritDoc}
*
* <p>This version also clamps the scrolling to the bounds of our child.
*/
@Override
public void scrollTo(int x, int y) {
// we rely on the fact the View.scrollBy calls scrollTo.
if (getChildCount() > 0) {
View child = getChildAt(0);
x = clamp(x, getWidth() - getPaddingLeft() - getPaddingRight(), child.getWidth());
y = clamp(y, getHeight() - getPaddingTop() - getPaddingBottom(), child.getHeight());
if (x != getScrollX() || y != getScrollY()) {
super.scrollTo(x, y);
}
}
}
@Override
public void setOverScrollMode(int mode) {
if (mode != OVER_SCROLL_NEVER) {
if (mEdgeGlowLeft == null) {
Context context = getContext();
mEdgeGlowLeft = new EdgeEffect(context);
mEdgeGlowRight = new EdgeEffect(context);
mEdgeGlowTop = new EdgeEffect(context);
mEdgeGlowBottom = new EdgeEffect(context);
}
} else {
mEdgeGlowLeft = null;
mEdgeGlowRight = null;
mEdgeGlowTop = null;
mEdgeGlowBottom = null;
}
super.setOverScrollMode(mode);
}
@SuppressWarnings("SuspiciousNameCombination")
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
if (mEdgeGlowLeft != null) {
final int scrollX = getScrollX();
final int scrollY = getScrollY();
final int width = getWidth();
final int height = getHeight();
if (!mEdgeGlowLeft.isFinished()) {
final int restoreCount = canvas.save();
canvas.rotate(270);
canvas.translate(-height - scrollY, Math.min(0, scrollX));
mEdgeGlowLeft.setSize(height, width);
if (mEdgeGlowLeft.draw(canvas)) {
ViewCompat.postInvalidateOnAnimation(this);
}
canvas.restoreToCount(restoreCount);
}
if (!mEdgeGlowRight.isFinished()) {
final int restoreCount = canvas.save();
canvas.rotate(90);
canvas.translate(scrollY, -(Math.max(getHorizontalScrollRange(), scrollX) + width));
mEdgeGlowRight.setSize(height, width);
if (mEdgeGlowRight.draw(canvas)) {
ViewCompat.postInvalidateOnAnimation(this);
}
canvas.restoreToCount(restoreCount);
}
if (!mEdgeGlowTop.isFinished()) {
final int restoreCount = canvas.save();
canvas.translate(scrollX, Math.min(0, scrollY));
mEdgeGlowTop.setSize(width, height);
if (mEdgeGlowTop.draw(canvas)) {
ViewCompat.postInvalidateOnAnimation(this);
}
canvas.restoreToCount(restoreCount);
}
if (!mEdgeGlowBottom.isFinished()) {
final int restoreCount = canvas.save();
canvas.translate(-width + scrollX, Math.max(getVerticalScrollRange(), scrollY) + height);
canvas.rotate(180, width, 0);
mEdgeGlowBottom.setSize(width, height);
if (mEdgeGlowBottom.draw(canvas)) {
ViewCompat.postInvalidateOnAnimation(this);
}
canvas.restoreToCount(restoreCount);
}
}
}
@Override
protected void onRestoreInstanceState(Parcelable state) {
if (getContext().getApplicationInfo().targetSdkVersion <= Build.VERSION_CODES.JELLY_BEAN_MR2) {
// Some old apps reused IDs in ways they shouldn't have.
// Don't break them, but they don't get scroll state restoration.
super.onRestoreInstanceState(state);
return;
}
Bundle saved = (Bundle) state;
super.onRestoreInstanceState(saved.getParcelable(KEY_SUPER));
mSavedState = saved;
requestLayout();
}
@Override
protected Parcelable onSaveInstanceState() {
if (getContext().getApplicationInfo().targetSdkVersion <= Build.VERSION_CODES.JELLY_BEAN_MR2) {
// Some old apps reused IDs in ways they shouldn't have.
// Don't break them, but they don't get scroll state restoration.
return super.onSaveInstanceState();
}
Bundle saved = new Bundle();
saved.putParcelable(KEY_SUPER, super.onSaveInstanceState());
saved.putInt(KEY_SCROLL_X, getScrollX());
saved.putInt(KEY_SCROLL_X, getScrollY());
return saved;
}
private static int clamp(int n, int my, int child) {
if (my >= child || n < 0) {
return 0;
}
if ((my + n) > child) {
return child - my;
}
return n;
}
}