/*
* Copyright (C) 2015 The Android Open Source Project
*
* 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 android.support.design.widget;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.support.annotation.ColorInt;
import android.support.annotation.DrawableRes;
import android.support.annotation.IntDef;
import android.support.annotation.Nullable;
import android.support.annotation.StyleRes;
import android.support.design.R;
import android.support.v4.content.ContextCompat;
import android.support.v4.view.GravityCompat;
import android.support.v4.view.ViewCompat;
import android.support.v4.view.WindowInsetsCompat;
import android.support.v7.widget.Toolbar;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.widget.FrameLayout;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
/**
* CollapsingToolbarLayout is a wrapper for {@link Toolbar} which implements a collapsing app bar.
* It is designed to be used as a direct child of a {@link AppBarLayout}.
* CollapsingToolbarLayout contains the following features:
*
* <h3>Collapsing title</h3>
* A title which is larger when the layout is fully visible but collapses and becomes smaller as
* the layout is scrolled off screen. You can set the title to display via
* {@link #setTitle(CharSequence)}. The title appearance can be tweaked via the
* {@code collapsedTextAppearance} and {@code expandedTextAppearance} attributes.
*
* <h3>Content scrim</h3>
* A full-bleed scrim which is show or hidden when the scroll position has hit a certain threshold.
* You can change this via {@link #setContentScrim(Drawable)}.
*
* <h3>Status bar scrim</h3>
* A scrim which is show or hidden behind the status bar when the scroll position has hit a certain
* threshold. You can change this via {@link #setStatusBarScrim(Drawable)}. This only works
* on {@link Build.VERSION_CODES#LOLLIPOP LOLLIPOP} devices when we set to fit system windows.
*
* <h3>Parallax scrolling children</h3>
* Child views can opt to be scrolled within this layout in a parallax fashion.
* See {@link LayoutParams#COLLAPSE_MODE_PARALLAX} and
* {@link LayoutParams#setParallaxMultiplier(float)}.
*
* <h3>Pinned position children</h3>
* Child views can opt to be pinned in space globally. This is useful when implementing a
* collapsing as it allows the {@link Toolbar} to be fixed in place even though this layout is
* moving. See {@link LayoutParams#COLLAPSE_MODE_PIN}.
*
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_collapsedTitleTextAppearance
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_expandedTitleTextAppearance
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_contentScrim
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_expandedTitleMargin
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_expandedTitleMarginStart
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_expandedTitleMarginEnd
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_expandedTitleMarginBottom
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_statusBarScrim
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_toolbarId
*/
public class CollapsingToolbarLayout extends FrameLayout {
private static final int SCRIM_ANIMATION_DURATION = 600;
private boolean mRefreshToolbar = true;
private int mToolbarId;
private Toolbar mToolbar;
private View mDummyView;
private int mExpandedMarginLeft;
private int mExpandedMarginTop;
private int mExpandedMarginRight;
private int mExpandedMarginBottom;
private final Rect mTmpRect = new Rect();
private final CollapsingTextHelper mCollapsingTextHelper;
private boolean mCollapsingTitleEnabled;
private Drawable mContentScrim;
private Drawable mStatusBarScrim;
private int mScrimAlpha;
private boolean mScrimsAreShown;
private ValueAnimatorCompat mScrimAnimator;
private AppBarLayout.OnOffsetChangedListener mOnOffsetChangedListener;
private int mCurrentOffset;
private WindowInsetsCompat mLastInsets;
public CollapsingToolbarLayout(Context context) {
this(context, null);
}
public CollapsingToolbarLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CollapsingToolbarLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mCollapsingTextHelper = new CollapsingTextHelper(this);
mCollapsingTextHelper.setTextSizeInterpolator(AnimationUtils.DECELERATE_INTERPOLATOR);
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.CollapsingToolbarLayout, defStyleAttr,
R.style.Widget_Design_CollapsingToolbar);
mCollapsingTextHelper.setExpandedTextGravity(
a.getInt(R.styleable.CollapsingToolbarLayout_expandedTitleGravity,
GravityCompat.START | Gravity.BOTTOM));
mCollapsingTextHelper.setCollapsedTextGravity(
a.getInt(R.styleable.CollapsingToolbarLayout_collapsedTitleGravity,
GravityCompat.START | Gravity.CENTER_VERTICAL));
mExpandedMarginLeft = mExpandedMarginTop = mExpandedMarginRight = mExpandedMarginBottom =
a.getDimensionPixelSize(R.styleable.CollapsingToolbarLayout_expandedTitleMargin, 0);
final boolean isRtl = ViewCompat.getLayoutDirection(this)
== ViewCompat.LAYOUT_DIRECTION_RTL;
if (a.hasValue(R.styleable.CollapsingToolbarLayout_expandedTitleMarginStart)) {
final int marginStart = a.getDimensionPixelSize(
R.styleable.CollapsingToolbarLayout_expandedTitleMarginStart, 0);
if (isRtl) {
mExpandedMarginRight = marginStart;
} else {
mExpandedMarginLeft = marginStart;
}
}
if (a.hasValue(R.styleable.CollapsingToolbarLayout_expandedTitleMarginEnd)) {
final int marginEnd = a.getDimensionPixelSize(
R.styleable.CollapsingToolbarLayout_expandedTitleMarginEnd, 0);
if (isRtl) {
mExpandedMarginLeft = marginEnd;
} else {
mExpandedMarginRight = marginEnd;
}
}
if (a.hasValue(R.styleable.CollapsingToolbarLayout_expandedTitleMarginTop)) {
mExpandedMarginTop = a.getDimensionPixelSize(
R.styleable.CollapsingToolbarLayout_expandedTitleMarginTop, 0);
}
if (a.hasValue(R.styleable.CollapsingToolbarLayout_expandedTitleMarginBottom)) {
mExpandedMarginBottom = a.getDimensionPixelSize(
R.styleable.CollapsingToolbarLayout_expandedTitleMarginBottom, 0);
}
mCollapsingTitleEnabled = a.getBoolean(
R.styleable.CollapsingToolbarLayout_titleEnabled, true);
setTitle(a.getText(R.styleable.CollapsingToolbarLayout_title));
// First load the default text appearances
mCollapsingTextHelper.setExpandedTextAppearance(
R.style.TextAppearance_Design_CollapsingToolbar_Expanded);
mCollapsingTextHelper.setCollapsedTextAppearance(
R.style.TextAppearance_AppCompat_Widget_ActionBar_Title);
// Now overlay any custom text appearances
if (a.hasValue(R.styleable.CollapsingToolbarLayout_expandedTitleTextAppearance)) {
mCollapsingTextHelper.setExpandedTextAppearance(
a.getResourceId(
R.styleable.CollapsingToolbarLayout_expandedTitleTextAppearance, 0));
}
if (a.hasValue(R.styleable.CollapsingToolbarLayout_collapsedTitleTextAppearance)) {
mCollapsingTextHelper.setCollapsedTextAppearance(
a.getResourceId(
R.styleable.CollapsingToolbarLayout_collapsedTitleTextAppearance, 0));
}
setContentScrim(a.getDrawable(R.styleable.CollapsingToolbarLayout_contentScrim));
setStatusBarScrim(a.getDrawable(R.styleable.CollapsingToolbarLayout_statusBarScrim));
mToolbarId = a.getResourceId(R.styleable.CollapsingToolbarLayout_toolbarId, -1);
a.recycle();
setWillNotDraw(false);
ViewCompat.setOnApplyWindowInsetsListener(this,
new android.support.v4.view.OnApplyWindowInsetsListener() {
@Override
public WindowInsetsCompat onApplyWindowInsets(View v,
WindowInsetsCompat insets) {
mLastInsets = insets;
requestLayout();
return insets.consumeSystemWindowInsets();
}
});
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
// Add an OnOffsetChangedListener if possible
final ViewParent parent = getParent();
if (parent instanceof AppBarLayout) {
if (mOnOffsetChangedListener == null) {
mOnOffsetChangedListener = new OffsetUpdateListener();
}
((AppBarLayout) parent).addOnOffsetChangedListener(mOnOffsetChangedListener);
}
}
@Override
protected void onDetachedFromWindow() {
// Remove our OnOffsetChangedListener if possible and it exists
final ViewParent parent = getParent();
if (mOnOffsetChangedListener != null && parent instanceof AppBarLayout) {
((AppBarLayout) parent).removeOnOffsetChangedListener(mOnOffsetChangedListener);
}
super.onDetachedFromWindow();
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
// If we don't have a toolbar, the scrim will be not be drawn in drawChild() below.
// Instead, we draw it here, before our collapsing text.
ensureToolbar();
if (mToolbar == null && mContentScrim != null && mScrimAlpha > 0) {
mContentScrim.mutate().setAlpha(mScrimAlpha);
mContentScrim.draw(canvas);
}
// Let the collapsing text helper draw it's text
if (mCollapsingTitleEnabled) {
mCollapsingTextHelper.draw(canvas);
}
// Now draw the status bar scrim
if (mStatusBarScrim != null && mScrimAlpha > 0) {
final int topInset = mLastInsets != null ? mLastInsets.getSystemWindowInsetTop() : 0;
if (topInset > 0) {
mStatusBarScrim.setBounds(0, -mCurrentOffset, getWidth(),
topInset - mCurrentOffset);
mStatusBarScrim.mutate().setAlpha(mScrimAlpha);
mStatusBarScrim.draw(canvas);
}
}
}
@Override
protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
// This is a little weird. Our scrim needs to be behind the Toolbar (if it is present),
// but in front of any other children which are behind it. To do this we intercept the
// drawChild() call, and draw our scrim first when drawing the toolbar
ensureToolbar();
if (child == mToolbar && mContentScrim != null && mScrimAlpha > 0) {
mContentScrim.mutate().setAlpha(mScrimAlpha);
mContentScrim.draw(canvas);
}
// Carry on drawing the child...
return super.drawChild(canvas, child, drawingTime);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
if (mContentScrim != null) {
mContentScrim.setBounds(0, 0, w, h);
}
}
private void ensureToolbar() {
if (!mRefreshToolbar) {
return;
}
Toolbar fallback = null, selected = null;
for (int i = 0, count = getChildCount(); i < count; i++) {
final View child = getChildAt(i);
if (child instanceof Toolbar) {
if (mToolbarId != -1) {
// There's a toolbar id set so try and find it...
if (mToolbarId == child.getId()) {
// We found the primary Toolbar, use it
selected = (Toolbar) child;
break;
}
if (fallback == null) {
// We'll record the first Toolbar as our fallback
fallback = (Toolbar) child;
}
} else {
// We don't have a id to check for so just use the first we come across
selected = (Toolbar) child;
break;
}
}
}
if (selected == null) {
// If we didn't find a primary Toolbar, use the fallback
selected = fallback;
}
mToolbar = selected;
updateDummyView();
mRefreshToolbar = false;
}
private void updateDummyView() {
if (!mCollapsingTitleEnabled && mDummyView != null) {
// If we have a dummy view and we have our title disabled, remove it from its parent
final ViewParent parent = mDummyView.getParent();
if (parent instanceof ViewGroup) {
((ViewGroup) parent).removeView(mDummyView);
}
}
if (mCollapsingTitleEnabled && mToolbar != null) {
if (mDummyView == null) {
mDummyView = new View(getContext());
}
if (mDummyView.getParent() == null) {
mToolbar.addView(mDummyView, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
}
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
ensureToolbar();
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
// Update our child view offset helpers
for (int i = 0, z = getChildCount(); i < z; i++) {
final View child = getChildAt(i);
if (mLastInsets != null && !ViewCompat.getFitsSystemWindows(child)) {
final int insetTop = mLastInsets.getSystemWindowInsetTop();
if (child.getTop() < insetTop) {
// If the child isn't set to fit system windows but is drawing within the inset
// offset it down
child.offsetTopAndBottom(insetTop);
}
}
getViewOffsetHelper(child).onViewLayout();
}
// Update the collapsed bounds by getting it's transformed bounds
if (mCollapsingTitleEnabled && mDummyView != null) {
ViewGroupUtils.getDescendantRect(this, mDummyView, mTmpRect);
mCollapsingTextHelper.setCollapsedBounds(mTmpRect.left, bottom - mTmpRect.height(),
mTmpRect.right, bottom);
// Update the expanded bounds
mCollapsingTextHelper.setExpandedBounds(
mExpandedMarginLeft,
mTmpRect.bottom + mExpandedMarginTop,
right - left - mExpandedMarginRight,
bottom - top - mExpandedMarginBottom);
mCollapsingTextHelper.recalculate();
}
// Finally, set our minimum height to enable proper AppBarLayout collapsing
if (mToolbar != null) {
if (mCollapsingTitleEnabled && TextUtils.isEmpty(mCollapsingTextHelper.getText())) {
// If we do not currently have a title, try and grab it from the Toolbar
mCollapsingTextHelper.setText(mToolbar.getTitle());
}
setMinimumHeight(mToolbar.getHeight());
}
}
private static ViewOffsetHelper getViewOffsetHelper(View view) {
ViewOffsetHelper offsetHelper = (ViewOffsetHelper) view.getTag(R.id.view_offset_helper);
if (offsetHelper == null) {
offsetHelper = new ViewOffsetHelper(view);
view.setTag(R.id.view_offset_helper, offsetHelper);
}
return offsetHelper;
}
/**
* Sets the title to be displayed by this view, if enabled.
*
* @see #setTitleEnabled(boolean)
* @see #getTitle()
*
* @attr ref R.styleable#CollapsingToolbarLayout_title
*/
public void setTitle(@Nullable CharSequence title) {
mCollapsingTextHelper.setText(title);
}
/**
* Returns the title currently being displayed by this view. If the title is not enabled, then
* this will return {@code null}.
*
* @attr ref R.styleable#CollapsingToolbarLayout_title
*/
@Nullable
public CharSequence getTitle() {
return mCollapsingTitleEnabled ? mCollapsingTextHelper.getText() : null;
}
/**
* Sets whether this view should display its own title.
*
* <p>The title displayed by this view will shrink and grow based on the scroll offset.</p>
*
* @see #setTitle(CharSequence)
* @see #isTitleEnabled()
*
* @attr ref R.styleable#CollapsingToolbarLayout_titleEnabled
*/
public void setTitleEnabled(boolean enabled) {
if (enabled != mCollapsingTitleEnabled) {
mCollapsingTitleEnabled = enabled;
updateDummyView();
requestLayout();
}
}
/**
* Returns whether this view is currently displaying its own title.
*
* @see #setTitleEnabled(boolean)
*
* @attr ref R.styleable#CollapsingToolbarLayout_titleEnabled
*/
public boolean isTitleEnabled() {
return mCollapsingTitleEnabled;
}
private void showScrim() {
if (!mScrimsAreShown) {
if (ViewCompat.isLaidOut(this) && !isInEditMode()) {
animateScrim(255);
} else {
setScrimAlpha(255);
}
mScrimsAreShown = true;
}
}
private void hideScrim() {
if (mScrimsAreShown) {
if (ViewCompat.isLaidOut(this) && !isInEditMode()) {
animateScrim(0);
} else {
setScrimAlpha(0);
}
mScrimsAreShown = false;
}
}
private void animateScrim(int targetAlpha) {
ensureToolbar();
if (mScrimAnimator == null) {
mScrimAnimator = ViewUtils.createAnimator();
mScrimAnimator.setDuration(SCRIM_ANIMATION_DURATION);
mScrimAnimator.setInterpolator(AnimationUtils.FAST_OUT_SLOW_IN_INTERPOLATOR);
mScrimAnimator.setUpdateListener(new ValueAnimatorCompat.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimatorCompat animator) {
setScrimAlpha(animator.getAnimatedIntValue());
}
});
} else if (mScrimAnimator.isRunning()) {
mScrimAnimator.cancel();
}
mScrimAnimator.setIntValues(mScrimAlpha, targetAlpha);
mScrimAnimator.start();
}
private void setScrimAlpha(int alpha) {
if (alpha != mScrimAlpha) {
final Drawable contentScrim = mContentScrim;
if (contentScrim != null && mToolbar != null) {
ViewCompat.postInvalidateOnAnimation(mToolbar);
}
mScrimAlpha = alpha;
ViewCompat.postInvalidateOnAnimation(CollapsingToolbarLayout.this);
}
}
/**
* Set the drawable to use for the content scrim from resources. Providing null will disable
* the scrim functionality.
*
* @param drawable the drawable to display
*
* @attr ref R.styleable#CollapsingToolbarLayout_contentScrim
* @see #getContentScrim()
*/
public void setContentScrim(@Nullable Drawable drawable) {
if (mContentScrim != drawable) {
if (mContentScrim != null) {
mContentScrim.setCallback(null);
}
mContentScrim = drawable;
drawable.setBounds(0, 0, getWidth(), getHeight());
drawable.setCallback(this);
drawable.mutate().setAlpha(mScrimAlpha);
ViewCompat.postInvalidateOnAnimation(this);
}
}
/**
* Set the color to use for the content scrim.
*
* @param color the color to display
*
* @attr ref R.styleable#CollapsingToolbarLayout_contentScrim
* @see #getContentScrim()
*/
public void setContentScrimColor(@ColorInt int color) {
setContentScrim(new ColorDrawable(color));
}
/**
* Set the drawable to use for the content scrim from resources.
*
* @param resId drawable resource id
*
* @attr ref R.styleable#CollapsingToolbarLayout_contentScrim
* @see #getContentScrim()
*/
public void setContentScrimResource(@DrawableRes int resId) {
setContentScrim(ContextCompat.getDrawable(getContext(), resId));
}
/**
* Returns the drawable which is used for the foreground scrim.
*
* @attr ref R.styleable#CollapsingToolbarLayout_contentScrim
* @see #setContentScrim(Drawable)
*/
public Drawable getContentScrim() {
return mContentScrim;
}
/**
* Set the drawable to use for the status bar scrim from resources.
* Providing null will disable the scrim functionality.
*
* <p>This scrim is only shown when we have been given a top system inset.</p>
*
* @param drawable the drawable to display
*
* @attr ref R.styleable#CollapsingToolbarLayout_statusBarScrim
* @see #getStatusBarScrim()
*/
public void setStatusBarScrim(@Nullable Drawable drawable) {
if (mStatusBarScrim != drawable) {
if (mStatusBarScrim != null) {
mStatusBarScrim.setCallback(null);
}
mStatusBarScrim = drawable;
drawable.setCallback(this);
drawable.mutate().setAlpha(mScrimAlpha);
ViewCompat.postInvalidateOnAnimation(this);
}
}
/**
* Set the color to use for the status bar scrim.
*
* <p>This scrim is only shown when we have been given a top system inset.</p>
*
* @param color the color to display
*
* @attr ref R.styleable#CollapsingToolbarLayout_statusBarScrim
* @see #getStatusBarScrim()
*/
public void setStatusBarScrimColor(@ColorInt int color) {
setStatusBarScrim(new ColorDrawable(color));
}
/**
* Set the drawable to use for the content scrim from resources.
*
* @param resId drawable resource id
*
* @attr ref R.styleable#CollapsingToolbarLayout_statusBarScrim
* @see #getStatusBarScrim()
*/
public void setStatusBarScrimResource(@DrawableRes int resId) {
setStatusBarScrim(ContextCompat.getDrawable(getContext(), resId));
}
/**
* Returns the drawable which is used for the status bar scrim.
*
* @attr ref R.styleable#CollapsingToolbarLayout_statusBarScrim
* @see #setStatusBarScrim(Drawable)
*/
public Drawable getStatusBarScrim() {
return mStatusBarScrim;
}
/**
* Sets the text color and size for the collapsed title from the specified
* TextAppearance resource.
*
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_collapsedTitleTextAppearance
*/
public void setCollapsedTitleTextAppearance(@StyleRes int resId) {
mCollapsingTextHelper.setCollapsedTextAppearance(resId);
}
/**
* Sets the text color of the collapsed title.
*
* @param color The new text color in ARGB format
*/
public void setCollapsedTitleTextColor(@ColorInt int color) {
mCollapsingTextHelper.setCollapsedTextColor(color);
}
/**
* Sets the horizontal alignment of the collapsed title and the vertical gravity that will
* be used when there is extra space in the collapsed bounds beyond what is required for
* the title itself.
*
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_collapsedTitleGravity
*/
public void setCollapsedTitleGravity(int gravity) {
mCollapsingTextHelper.setExpandedTextGravity(gravity);
}
/**
* Returns the horizontal and vertical alignment for title when collapsed.
*
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_collapsedTitleGravity
*/
public int getCollapsedTitleGravity() {
return mCollapsingTextHelper.getCollapsedTextGravity();
}
/**
* Sets the text color and size for the expanded title from the specified
* TextAppearance resource.
*
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_expandedTitleTextAppearance
*/
public void setExpandedTitleTextAppearance(@StyleRes int resId) {
mCollapsingTextHelper.setExpandedTextAppearance(resId);
}
/**
* Sets the text color of the expanded title.
*
* @param color The new text color in ARGB format
*/
public void setExpandedTitleColor(@ColorInt int color) {
mCollapsingTextHelper.setExpandedTextColor(color);
}
/**
* Sets the horizontal alignment of the expanded title and the vertical gravity that will
* be used when there is extra space in the expanded bounds beyond what is required for
* the title itself.
*
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_expandedTitleGravity
*/
public void setExpandedTitleGravity(int gravity) {
mCollapsingTextHelper.setExpandedTextGravity(gravity);
}
/**
* Returns the horizontal and vertical alignment for title when expanded.
*
* @attr ref android.support.design.R.styleable#CollapsingToolbarLayout_expandedTitleGravity
*/
public int getExpandedTitleGravity() {
return mCollapsingTextHelper.getExpandedTextGravity();
}
/**
* The additional offset used to define when to trigger the scrim visibility change.
*/
final int getScrimTriggerOffset() {
return 2 * ViewCompat.getMinimumHeight(this);
}
@Override
protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
return p instanceof LayoutParams;
}
@Override
protected LayoutParams generateDefaultLayoutParams() {
return new LayoutParams(super.generateDefaultLayoutParams());
}
@Override
public FrameLayout.LayoutParams generateLayoutParams(AttributeSet attrs) {
return new LayoutParams(getContext(), attrs);
}
@Override
protected FrameLayout.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
return new LayoutParams(p);
}
public static class LayoutParams extends FrameLayout.LayoutParams {
private static final float DEFAULT_PARALLAX_MULTIPLIER = 0.5f;
/** @hide */
@IntDef({
COLLAPSE_MODE_OFF,
COLLAPSE_MODE_PIN,
COLLAPSE_MODE_PARALLAX
})
@Retention(RetentionPolicy.SOURCE)
@interface CollapseMode {}
/**
* The view will act as normal with no collapsing behavior.
*/
public static final int COLLAPSE_MODE_OFF = 0;
/**
* The view will pin in place until it reaches the bottom of the
* {@link CollapsingToolbarLayout}.
*/
public static final int COLLAPSE_MODE_PIN = 1;
/**
* The view will scroll in a parallax fashion. See {@link #setParallaxMultiplier(float)}
* to change the multiplier used.
*/
public static final int COLLAPSE_MODE_PARALLAX = 2;
int mCollapseMode = COLLAPSE_MODE_OFF;
float mParallaxMult = DEFAULT_PARALLAX_MULTIPLIER;
public LayoutParams(Context c, AttributeSet attrs) {
super(c, attrs);
TypedArray a = c.obtainStyledAttributes(attrs,
R.styleable.CollapsingAppBarLayout_LayoutParams);
mCollapseMode = a.getInt(
R.styleable.CollapsingAppBarLayout_LayoutParams_layout_collapseMode,
COLLAPSE_MODE_OFF);
setParallaxMultiplier(a.getFloat(
R.styleable.CollapsingAppBarLayout_LayoutParams_layout_collapseParallaxMultiplier,
DEFAULT_PARALLAX_MULTIPLIER));
a.recycle();
}
public LayoutParams(int width, int height) {
super(width, height);
}
public LayoutParams(int width, int height, int gravity) {
super(width, height, gravity);
}
public LayoutParams(ViewGroup.LayoutParams p) {
super(p);
}
public LayoutParams(MarginLayoutParams source) {
super(source);
}
public LayoutParams(FrameLayout.LayoutParams source) {
super(source);
}
/**
* Set the collapse mode.
*
* @param collapseMode one of {@link #COLLAPSE_MODE_OFF}, {@link #COLLAPSE_MODE_PIN}
* or {@link #COLLAPSE_MODE_PARALLAX}.
*/
public void setCollapseMode(@CollapseMode int collapseMode) {
mCollapseMode = collapseMode;
}
/**
* Returns the requested collapse mode.
*
* @return the current mode. One of {@link #COLLAPSE_MODE_OFF}, {@link #COLLAPSE_MODE_PIN}
* or {@link #COLLAPSE_MODE_PARALLAX}.
*/
@CollapseMode
public int getCollapseMode() {
return mCollapseMode;
}
/**
* Set the parallax scroll multiplier used in conjunction with
* {@link #COLLAPSE_MODE_PARALLAX}. A value of {@code 0.0} indicates no movement at all,
* {@code 1.0f} indicates normal scroll movement.
*
* @param multiplier the multiplier.
*
* @see #getParallaxMultiplier()
*/
public void setParallaxMultiplier(float multiplier) {
mParallaxMult = multiplier;
}
/**
* Returns the parallax scroll multiplier used in conjunction with
* {@link #COLLAPSE_MODE_PARALLAX}.
*
* @see #setParallaxMultiplier(float)
*/
public float getParallaxMultiplier() {
return mParallaxMult;
}
}
private class OffsetUpdateListener implements AppBarLayout.OnOffsetChangedListener {
@Override
public void onOffsetChanged(AppBarLayout layout, int verticalOffset) {
mCurrentOffset = verticalOffset;
final int insetTop = mLastInsets != null ? mLastInsets.getSystemWindowInsetTop() : 0;
final int scrollRange = layout.getTotalScrollRange();
for (int i = 0, z = getChildCount(); i < z; i++) {
final View child = getChildAt(i);
final LayoutParams lp = (LayoutParams) child.getLayoutParams();
final ViewOffsetHelper offsetHelper = getViewOffsetHelper(child);
switch (lp.mCollapseMode) {
case LayoutParams.COLLAPSE_MODE_PIN:
if (getHeight() - insetTop + verticalOffset >= child.getHeight()) {
offsetHelper.setTopAndBottomOffset(-verticalOffset);
}
break;
case LayoutParams.COLLAPSE_MODE_PARALLAX:
offsetHelper.setTopAndBottomOffset(
Math.round(-verticalOffset * lp.mParallaxMult));
break;
}
}
// Show or hide the scrims if needed
if (mContentScrim != null || mStatusBarScrim != null) {
if (getHeight() + verticalOffset < getScrimTriggerOffset() + insetTop) {
showScrim();
} else {
hideScrim();
}
}
if (mStatusBarScrim != null && insetTop > 0) {
ViewCompat.postInvalidateOnAnimation(CollapsingToolbarLayout.this);
}
// Update the collapsing text's fraction
final int expandRange = getHeight() - ViewCompat.getMinimumHeight(
CollapsingToolbarLayout.this) - insetTop;
mCollapsingTextHelper.setExpansionFraction(
Math.abs(verticalOffset) / (float) expandRange);
if (Math.abs(verticalOffset) == scrollRange) {
// If we have some pinned children, and we're offset to only show those views,
// we want to be elevate
ViewCompat.setElevation(layout, layout.getTargetElevation());
} else {
// Otherwise, we're inline with the content
ViewCompat.setElevation(layout, 0f);
}
}
}
}