/*
* Copyright (C) 2012 Jake Wharton 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.tweetlanes.android.core.widget.viewpagerindicator;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Parcel;
import android.os.Parcelable;
import android.support.v4.view.MotionEventCompat;
import android.support.v4.view.ViewConfigurationCompat;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import com.tweetlanes.android.core.R;
/**
* Draws a line for each page. The current page line is colored differently than
* the unselected page lines.
*/
public class UnderlinePageIndicator extends View implements PageIndicator {
private static final int INVALID_POINTER = -1;
private static final int FADE_FRAME_MS = 30;
private final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
private boolean mFades;
private int mFadeDelay;
private int mFadeLength;
private int mFadeBy;
private ViewPager mViewPager;
private ViewPager.OnPageChangeListener mListener;
private int mScrollState;
private int mCurrentPage;
private float mPositionOffset;
private int mTouchSlop;
private float mLastMotionX = -1;
private int mActivePointerId = INVALID_POINTER;
private boolean mIsDragging;
private final Runnable mFadeRunnable = new Runnable() {
@Override
public void run() {
final int alpha = Math.max(mPaint.getAlpha() - mFadeBy, 0);
mPaint.setAlpha(alpha);
invalidate();
if (alpha > 0) {
postDelayed(this, FADE_FRAME_MS);
}
}
};
public UnderlinePageIndicator(Context context) {
this(context, null);
}
public UnderlinePageIndicator(Context context, AttributeSet attrs) {
this(context, attrs, R.attr.vpiUnderlinePageIndicatorStyle);
}
public UnderlinePageIndicator(Context context, AttributeSet attrs,
int defStyle) {
super(context, attrs, defStyle);
if (isInEditMode()) return;
final Resources res = getResources();
// Load defaults from resources
final boolean defaultFades = res
.getBoolean(R.bool.default_underline_indicator_fades);
final int defaultFadeDelay = res
.getInteger(R.integer.default_underline_indicator_fade_delay);
final int defaultFadeLength = res
.getInteger(R.integer.default_underline_indicator_fade_length);
final int defaultSelectedColor = res
.getColor(R.color.default_underline_indicator_selected_color);
// Retrieve styles attributes
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.UnderlinePageIndicator, defStyle, 0);
setFades(a.getBoolean(R.styleable.UnderlinePageIndicator_fades,
defaultFades));
setSelectedColor(a.getColor(
R.styleable.UnderlinePageIndicator_selectedColor,
defaultSelectedColor));
setFadeDelay(a.getInteger(R.styleable.UnderlinePageIndicator_fadeDelay,
defaultFadeDelay));
setFadeLength(a.getInteger(
R.styleable.UnderlinePageIndicator_fadeLength,
defaultFadeLength));
a.recycle();
final ViewConfiguration configuration = ViewConfiguration.get(context);
mTouchSlop = ViewConfigurationCompat
.getScaledPagingTouchSlop(configuration);
}
public void setFades(boolean fades) {
if (fades != mFades) {
mFades = fades;
if (fades) {
post(mFadeRunnable);
} else {
removeCallbacks(mFadeRunnable);
mPaint.setAlpha(0xFF);
invalidate();
}
}
}
void setFadeDelay(int fadeDelay) {
mFadeDelay = fadeDelay;
}
void setFadeLength(int fadeLength) {
mFadeLength = fadeLength;
mFadeBy = 0xFF / (mFadeLength / FADE_FRAME_MS);
}
void setSelectedColor(int selectedColor) {
mPaint.setColor(selectedColor);
invalidate();
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mViewPager == null) {
return;
}
final int count = mViewPager.getAdapter().getCount();
if (count == 0) {
return;
}
if (mCurrentPage >= count) {
setCurrentItem(count - 1);
return;
}
final int paddingLeft = getPaddingLeft();
final float pageWidth = (getWidth() - paddingLeft - getPaddingRight())
/ (1f * count);
final float left = paddingLeft + pageWidth
* (mCurrentPage + mPositionOffset);
final float right = left + pageWidth;
final float top = getPaddingTop();
final float bottom = getHeight() - getPaddingBottom();
canvas.drawRect(left, top, right, bottom, mPaint);
}
public boolean onTouchEvent(MotionEvent ev) {
if (super.onTouchEvent(ev)) {
return true;
}
if ((mViewPager == null) || (mViewPager.getAdapter().getCount() == 0)) {
return false;
}
final int action = ev.getAction();
switch (action & MotionEventCompat.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
mLastMotionX = ev.getX();
break;
case MotionEvent.ACTION_MOVE: {
final int activePointerIndex = MotionEventCompat.findPointerIndex(
ev, mActivePointerId);
final float x = MotionEventCompat.getX(ev, activePointerIndex);
final float deltaX = x - mLastMotionX;
if (!mIsDragging) {
if (Math.abs(deltaX) > mTouchSlop) {
mIsDragging = true;
}
}
if (mIsDragging) {
mLastMotionX = x;
if (mViewPager.isFakeDragging() || mViewPager.beginFakeDrag()) {
mViewPager.fakeDragBy(deltaX);
}
}
break;
}
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
if (!mIsDragging) {
final int count = mViewPager.getAdapter().getCount();
final int width = getWidth();
final float halfWidth = width / 2f;
final float sixthWidth = width / 6f;
if ((mCurrentPage > 0) && (ev.getX() < halfWidth - sixthWidth)) {
mViewPager.setCurrentItem(mCurrentPage - 1);
return true;
} else if ((mCurrentPage < count - 1)
&& (ev.getX() > halfWidth + sixthWidth)) {
mViewPager.setCurrentItem(mCurrentPage + 1);
return true;
}
}
mIsDragging = false;
mActivePointerId = INVALID_POINTER;
if (mViewPager.isFakeDragging()) mViewPager.endFakeDrag();
break;
case MotionEventCompat.ACTION_POINTER_DOWN: {
final int index = MotionEventCompat.getActionIndex(ev);
mLastMotionX = MotionEventCompat.getX(ev, index);
mActivePointerId = MotionEventCompat.getPointerId(ev, index);
break;
}
case MotionEventCompat.ACTION_POINTER_UP:
final int pointerIndex = MotionEventCompat.getActionIndex(ev);
final int pointerId = MotionEventCompat.getPointerId(ev,
pointerIndex);
if (pointerId == mActivePointerId) {
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mActivePointerId = MotionEventCompat.getPointerId(ev,
newPointerIndex);
}
mLastMotionX = MotionEventCompat.getX(ev,
MotionEventCompat.findPointerIndex(ev, mActivePointerId));
break;
}
return true;
}
@Override
public void setViewPager(ViewPager viewPager) {
if (mViewPager == viewPager) {
return;
}
if (mViewPager != null) {
// Clear us from the old pager.
mViewPager.setOnPageChangeListener(null);
}
if (viewPager.getAdapter() == null) {
throw new IllegalStateException(
"ViewPager does not have adapter instance.");
}
mViewPager = viewPager;
mViewPager.setOnPageChangeListener(this);
invalidate();
post(new Runnable() {
@Override
public void run() {
if (mFades) {
post(mFadeRunnable);
}
}
});
}
@Override
public void setViewPager(ViewPager view, int initialPosition) {
setViewPager(view);
setCurrentItem(initialPosition);
}
@Override
public void setCurrentItem(int item) {
if (mViewPager == null) {
throw new IllegalStateException("ViewPager has not been bound.");
}
mViewPager.setCurrentItem(item);
mCurrentPage = item;
invalidate();
}
@Override
public void notifyDataSetChanged() {
invalidate();
}
@Override
public void onPageScrollStateChanged(int state) {
mScrollState = state;
if (mListener != null) {
mListener.onPageScrollStateChanged(state);
}
}
@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
mCurrentPage = position;
mPositionOffset = positionOffset;
if (mFades) {
if (positionOffsetPixels > 0) {
removeCallbacks(mFadeRunnable);
mPaint.setAlpha(0xFF);
} else if (mScrollState != ViewPager.SCROLL_STATE_DRAGGING) {
postDelayed(mFadeRunnable, mFadeDelay);
}
}
invalidate();
if (mListener != null) {
mListener.onPageScrolled(position, positionOffset,
positionOffsetPixels);
}
}
@Override
public void onPageSelected(int position) {
if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {
mCurrentPage = position;
mPositionOffset = 0;
invalidate();
mFadeRunnable.run();
}
if (mListener != null) {
mListener.onPageSelected(position);
}
}
@Override
public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {
mListener = listener;
}
@Override
public void onRestoreInstanceState(Parcelable state) {
SavedState savedState = (SavedState) state;
super.onRestoreInstanceState(savedState.getSuperState());
mCurrentPage = savedState.currentPage;
requestLayout();
}
@Override
public Parcelable onSaveInstanceState() {
Parcelable superState = super.onSaveInstanceState();
SavedState savedState = new SavedState(superState);
savedState.currentPage = mCurrentPage;
return savedState;
}
static class SavedState extends BaseSavedState {
int currentPage;
public SavedState(Parcelable superState) {
super(superState);
}
private SavedState(Parcel in) {
super(in);
currentPage = in.readInt();
}
@Override
public void writeToParcel(Parcel dest, int flags) {
super.writeToParcel(dest, flags);
dest.writeInt(currentPage);
}
public static final Creator<SavedState> CREATOR = new Creator<SavedState>() {
@Override
public SavedState createFromParcel(Parcel in) {
return new SavedState(in);
}
@Override
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
}
}