com/android/internal/widget/WatchListDecorLayout.java - platform/prebuilts/fullsdk/sources/android-31 - Git at Google

 /*
  * Copyright (C) 2016 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 com.android.internal.widget;

 import android.content.Context;
 import android.graphics.drawable.Drawable;
 import android.graphics.Rect;
 import android.util.AttributeSet;
 import android.view.Gravity;
 import android.view.View;
 import android.view.ViewTreeObserver;
 import android.widget.ListView;
 import android.widget.FrameLayout;

 import java.util.ArrayList;


 /**
  * Layout for the decor for ListViews on watch-type devices with small screens.
  * <p>
  * Supports one panel with the gravity set to top, and one panel with gravity set to bottom.
  * <p>
  * Use with one ListView child. The top and bottom panels will track the ListView's scrolling.
  * If there is no ListView child, it will act like a normal FrameLayout.
  */
 public class WatchListDecorLayout extends FrameLayout
         implements ViewTreeObserver.OnScrollChangedListener {

     private int mForegroundPaddingLeft = 0;
     private int mForegroundPaddingTop = 0;
     private int mForegroundPaddingRight = 0;
     private int mForegroundPaddingBottom = 0;

     private final ArrayList<View> mMatchParentChildren = new ArrayList<>(1);

     /** Track the amount the ListView has to scroll up to account for padding change difference. */
     private int mPendingScroll;
     private View mBottomPanel;
     private View mTopPanel;
     private ListView mListView;
     private ViewTreeObserver mObserver;


     public WatchListDecorLayout(Context context, AttributeSet attrs) {
         super(context, attrs);
     }

     public WatchListDecorLayout(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
     }

     public WatchListDecorLayout(
             Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
         super(context, attrs, defStyleAttr, defStyleRes);
     }

     @Override
     protected void onAttachedToWindow() {
         super.onAttachedToWindow();

         mPendingScroll = 0;

         for (int i = 0; i < getChildCount(); ++i) {
             View child = getChildAt(i);
             if (child instanceof ListView) {
                 if (mListView != null) {
                     throw new IllegalArgumentException("only one ListView child allowed");
                 }
                 mListView = (ListView) child;

                 mListView.setNestedScrollingEnabled(true);
                 mObserver = mListView.getViewTreeObserver();
                 mObserver.addOnScrollChangedListener(this);
             } else {
                 int gravity = (((LayoutParams) child.getLayoutParams()).gravity
                         & Gravity.VERTICAL_GRAVITY_MASK);
                 if (gravity == Gravity.TOP && mTopPanel == null) {
                     mTopPanel = child;
                 } else if (gravity == Gravity.BOTTOM && mBottomPanel == null) {
                     mBottomPanel = child;
                 }
             }
         }
     }

     @Override
     public void onDetachedFromWindow() {
         mListView = null;
         mBottomPanel = null;
         mTopPanel = null;
         if (mObserver != null) {
             if (mObserver.isAlive()) {
                 mObserver.removeOnScrollChangedListener(this);
             }
             mObserver = null;
         }
     }

     private void applyMeasureToChild(View child, int widthMeasureSpec, int heightMeasureSpec) {
         final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();

         final int childWidthMeasureSpec;
         if (lp.width == LayoutParams.MATCH_PARENT) {
             final int width = Math.max(0, getMeasuredWidth()
                     - getPaddingLeftWithForeground() - getPaddingRightWithForeground()
                     - lp.leftMargin - lp.rightMargin);
             childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(
                     width, MeasureSpec.EXACTLY);
         } else {
             childWidthMeasureSpec = getChildMeasureSpec(widthMeasureSpec,
                     getPaddingLeftWithForeground() + getPaddingRightWithForeground() +
                     lp.leftMargin + lp.rightMargin,
                     lp.width);
         }

         final int childHeightMeasureSpec;
         if (lp.height == LayoutParams.MATCH_PARENT) {
             final int height = Math.max(0, getMeasuredHeight()
                     - getPaddingTopWithForeground() - getPaddingBottomWithForeground()
                     - lp.topMargin - lp.bottomMargin);
             childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
                     height, MeasureSpec.EXACTLY);
         } else {
             childHeightMeasureSpec = getChildMeasureSpec(heightMeasureSpec,
                     getPaddingTopWithForeground() + getPaddingBottomWithForeground() +
                     lp.topMargin + lp.bottomMargin,
                     lp.height);
         }

         child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
     }

     private int measureAndGetHeight(View child, int widthMeasureSpec, int heightMeasureSpec) {
         if (child != null) {
             if (child.getVisibility() != GONE) {
                 applyMeasureToChild(mBottomPanel, widthMeasureSpec, heightMeasureSpec);
                 return child.getMeasuredHeight();
             } else if (getMeasureAllChildren()) {
                 applyMeasureToChild(mBottomPanel, widthMeasureSpec, heightMeasureSpec);
             }
         }
         return 0;
     }

     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         int count = getChildCount();

         final boolean measureMatchParentChildren =
                 MeasureSpec.getMode(widthMeasureSpec) != MeasureSpec.EXACTLY ||
                 MeasureSpec.getMode(heightMeasureSpec) != MeasureSpec.EXACTLY;
         mMatchParentChildren.clear();

         int maxHeight = 0;
         int maxWidth = 0;
         int childState = 0;

         for (int i = 0; i < count; i++) {
             final View child = getChildAt(i);
             if (getMeasureAllChildren() || child.getVisibility() != GONE) {
                 measureChildWithMargins(child, widthMeasureSpec, 0, heightMeasureSpec, 0);
                 final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                 maxWidth = Math.max(maxWidth,
                         child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin);
                 maxHeight = Math.max(maxHeight,
                         child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin);
                 childState = combineMeasuredStates(childState, child.getMeasuredState());
                 if (measureMatchParentChildren) {
                     if (lp.width == LayoutParams.MATCH_PARENT ||
                             lp.height == LayoutParams.MATCH_PARENT) {
                         mMatchParentChildren.add(child);
                     }
                 }
             }
         }

         // Account for padding too
         maxWidth += getPaddingLeftWithForeground() + getPaddingRightWithForeground();
         maxHeight += getPaddingTopWithForeground() + getPaddingBottomWithForeground();

         // Check against our minimum height and width
         maxHeight = Math.max(maxHeight, getSuggestedMinimumHeight());
         maxWidth = Math.max(maxWidth, getSuggestedMinimumWidth());

         // Check against our foreground's minimum height and width
         final Drawable drawable = getForeground();
         if (drawable != null) {
             maxHeight = Math.max(maxHeight, drawable.getMinimumHeight());
             maxWidth = Math.max(maxWidth, drawable.getMinimumWidth());
         }

         setMeasuredDimension(resolveSizeAndState(maxWidth, widthMeasureSpec, childState),
                 resolveSizeAndState(maxHeight, heightMeasureSpec,
                         childState << MEASURED_HEIGHT_STATE_SHIFT));

         if (mListView != null) {
             if (mPendingScroll != 0) {
                 mListView.scrollListBy(mPendingScroll);
                 mPendingScroll = 0;
             }

             int paddingTop = Math.max(mListView.getPaddingTop(),
                     measureAndGetHeight(mTopPanel, widthMeasureSpec, heightMeasureSpec));
             int paddingBottom = Math.max(mListView.getPaddingBottom(),
                     measureAndGetHeight(mBottomPanel, widthMeasureSpec, heightMeasureSpec));

             if (paddingTop != mListView.getPaddingTop()
                     || paddingBottom != mListView.getPaddingBottom()) {
                 mPendingScroll += mListView.getPaddingTop() - paddingTop;
                 mListView.setPadding(
                         mListView.getPaddingLeft(), paddingTop,
                         mListView.getPaddingRight(), paddingBottom);
             }
         }

         count = mMatchParentChildren.size();
         if (count > 1) {
             for (int i = 0; i < count; i++) {
                 final View child = mMatchParentChildren.get(i);
                 if (mListView == null || (child != mTopPanel && child != mBottomPanel)) {
                     applyMeasureToChild(child, widthMeasureSpec, heightMeasureSpec);
                 }
             }
         }
     }

     @Override
     public void setForegroundGravity(int foregroundGravity) {
         if (getForegroundGravity() != foregroundGravity) {
             super.setForegroundGravity(foregroundGravity);

             // calling get* again here because the set above may apply default constraints
             final Drawable foreground = getForeground();
             if (getForegroundGravity() == Gravity.FILL && foreground != null) {
                 Rect padding = new Rect();
                 if (foreground.getPadding(padding)) {
                     mForegroundPaddingLeft = padding.left;
                     mForegroundPaddingTop = padding.top;
                     mForegroundPaddingRight = padding.right;
                     mForegroundPaddingBottom = padding.bottom;
                 }
             } else {
                 mForegroundPaddingLeft = 0;
                 mForegroundPaddingTop = 0;
                 mForegroundPaddingRight = 0;
                 mForegroundPaddingBottom = 0;
             }
         }
     }

     private int getPaddingLeftWithForeground() {
         return isForegroundInsidePadding() ? Math.max(mPaddingLeft, mForegroundPaddingLeft) :
             mPaddingLeft + mForegroundPaddingLeft;
     }

     private int getPaddingRightWithForeground() {
         return isForegroundInsidePadding() ? Math.max(mPaddingRight, mForegroundPaddingRight) :
             mPaddingRight + mForegroundPaddingRight;
     }

     private int getPaddingTopWithForeground() {
         return isForegroundInsidePadding() ? Math.max(mPaddingTop, mForegroundPaddingTop) :
             mPaddingTop + mForegroundPaddingTop;
     }

     private int getPaddingBottomWithForeground() {
         return isForegroundInsidePadding() ? Math.max(mPaddingBottom, mForegroundPaddingBottom) :
             mPaddingBottom + mForegroundPaddingBottom;
     }

     @Override
     public void onScrollChanged() {
         if (mListView == null) {
             return;
         }

         if (mTopPanel != null) {
             if (mListView.getChildCount() > 0) {
                 if (mListView.getFirstVisiblePosition() == 0) {
                     View firstChild = mListView.getChildAt(0);
                     setScrolling(mTopPanel,
                             firstChild.getY() - mTopPanel.getHeight() - mTopPanel.getTop());
                 } else {
                     // shift to hide the frame, last child is not the last position
                     setScrolling(mTopPanel, -mTopPanel.getHeight());
                 }
             } else {
                 setScrolling(mTopPanel, 0); // no visible child, fallback to default behaviour
             }
         }

         if (mBottomPanel != null) {
             if (mListView.getChildCount() > 0) {
                 if (mListView.getLastVisiblePosition() >= mListView.getCount() - 1) {
                     View lastChild = mListView.getChildAt(mListView.getChildCount() - 1);
                     setScrolling(mBottomPanel, Math.max(
                             0,
                             lastChild.getY() + lastChild.getHeight() - mBottomPanel.getTop()));
                 } else {
                     // shift to hide the frame, last child is not the last position
                     setScrolling(mBottomPanel, mBottomPanel.getHeight());
                 }
             } else {
                 setScrolling(mBottomPanel, 0); // no visible child, fallback to default behaviour
             }
         }
     }

     /** Only set scrolling for the panel if there is a change in its translationY. */
     private void setScrolling(View panel, float translationY) {
         if (panel.getTranslationY() != translationY) {
             panel.setTranslationY(translationY);
         }
     }
 }
	/*
	* Copyright (C) 2016 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 com.android.internal.widget;

	import android.content.Context;
	import android.graphics.drawable.Drawable;
	import android.graphics.Rect;
	import android.util.AttributeSet;
	import android.view.Gravity;
	import android.view.View;
	import android.view.ViewTreeObserver;
	import android.widget.ListView;
	import android.widget.FrameLayout;

	import java.util.ArrayList;


	/**
	* Layout for the decor for ListViews on watch-type devices with small screens.
	* <p>
	* Supports one panel with the gravity set to top, and one panel with gravity set to bottom.
	* <p>
	* Use with one ListView child. The top and bottom panels will track the ListView's scrolling.
	* If there is no ListView child, it will act like a normal FrameLayout.
	*/
	public class WatchListDecorLayout extends FrameLayout
	implements ViewTreeObserver.OnScrollChangedListener {

	private int mForegroundPaddingLeft = 0;
	private int mForegroundPaddingTop = 0;
	private int mForegroundPaddingRight = 0;
	private int mForegroundPaddingBottom = 0;

	private final ArrayList<View> mMatchParentChildren = new ArrayList<>(1);

	/** Track the amount the ListView has to scroll up to account for padding change difference. */
	private int mPendingScroll;
	private View mBottomPanel;
	private View mTopPanel;
	private ListView mListView;
	private ViewTreeObserver mObserver;


	public WatchListDecorLayout(Context context, AttributeSet attrs) {
	super(context, attrs);
	}

	public WatchListDecorLayout(Context context, AttributeSet attrs, int defStyleAttr) {
	super(context, attrs, defStyleAttr);
	}

	public WatchListDecorLayout(
	Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
	super(context, attrs, defStyleAttr, defStyleRes);
	}

	@Override
	protected void onAttachedToWindow() {
	super.onAttachedToWindow();

	mPendingScroll = 0;

	for (int i = 0; i < getChildCount(); ++i) {
	View child = getChildAt(i);
	if (child instanceof ListView) {
	if (mListView != null) {
	throw new IllegalArgumentException("only one ListView child allowed");
	}
	mListView = (ListView) child;

	mListView.setNestedScrollingEnabled(true);
	mObserver = mListView.getViewTreeObserver();
	mObserver.addOnScrollChangedListener(this);
	} else {
	int gravity = (((LayoutParams) child.getLayoutParams()).gravity
	& Gravity.VERTICAL_GRAVITY_MASK);
	if (gravity == Gravity.TOP && mTopPanel == null) {
	mTopPanel = child;
	} else if (gravity == Gravity.BOTTOM && mBottomPanel == null) {
	mBottomPanel = child;
	}
	}
	}
	}

	@Override
	public void onDetachedFromWindow() {
	mListView = null;
	mBottomPanel = null;
	mTopPanel = null;
	if (mObserver != null) {
	if (mObserver.isAlive()) {
	mObserver.removeOnScrollChangedListener(this);
	}
	mObserver = null;
	}
	}

	private void applyMeasureToChild(View child, int widthMeasureSpec, int heightMeasureSpec) {
	final MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();

	final int childWidthMeasureSpec;
	if (lp.width == LayoutParams.MATCH_PARENT) {
	final int width = Math.max(0, getMeasuredWidth()
	- getPaddingLeftWithForeground() - getPaddingRightWithForeground()
	- lp.leftMargin - lp.rightMargin);
	childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(
	width, MeasureSpec.EXACTLY);
	} else {
	childWidthMeasureSpec = getChildMeasureSpec(widthMeasureSpec,
	getPaddingLeftWithForeground() + getPaddingRightWithForeground() +
	lp.leftMargin + lp.rightMargin,
	lp.width);
	}

	final int childHeightMeasureSpec;
	if (lp.height == LayoutParams.MATCH_PARENT) {
	final int height = Math.max(0, getMeasuredHeight()
	- getPaddingTopWithForeground() - getPaddingBottomWithForeground()
	- lp.topMargin - lp.bottomMargin);
	childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
	height, MeasureSpec.EXACTLY);
	} else {
	childHeightMeasureSpec = getChildMeasureSpec(heightMeasureSpec,
	getPaddingTopWithForeground() + getPaddingBottomWithForeground() +
	lp.topMargin + lp.bottomMargin,
	lp.height);
	}

	child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
	}

	private int measureAndGetHeight(View child, int widthMeasureSpec, int heightMeasureSpec) {
	if (child != null) {
	if (child.getVisibility() != GONE) {
	applyMeasureToChild(mBottomPanel, widthMeasureSpec, heightMeasureSpec);
	return child.getMeasuredHeight();
	} else if (getMeasureAllChildren()) {
	applyMeasureToChild(mBottomPanel, widthMeasureSpec, heightMeasureSpec);
	}
	}
	return 0;
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
	int count = getChildCount();

	final boolean measureMatchParentChildren =
	MeasureSpec.getMode(widthMeasureSpec) != MeasureSpec.EXACTLY \|\|
	MeasureSpec.getMode(heightMeasureSpec) != MeasureSpec.EXACTLY;
	mMatchParentChildren.clear();

	int maxHeight = 0;
	int maxWidth = 0;
	int childState = 0;

	for (int i = 0; i < count; i++) {
	final View child = getChildAt(i);
	if (getMeasureAllChildren() \|\| child.getVisibility() != GONE) {
	measureChildWithMargins(child, widthMeasureSpec, 0, heightMeasureSpec, 0);
	final LayoutParams lp = (LayoutParams) child.getLayoutParams();
	maxWidth = Math.max(maxWidth,
	child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin);
	maxHeight = Math.max(maxHeight,
	child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin);
	childState = combineMeasuredStates(childState, child.getMeasuredState());
	if (measureMatchParentChildren) {
	if (lp.width == LayoutParams.MATCH_PARENT \|\|
	lp.height == LayoutParams.MATCH_PARENT) {
	mMatchParentChildren.add(child);
	}
	}
	}
	}

	// Account for padding too
	maxWidth += getPaddingLeftWithForeground() + getPaddingRightWithForeground();
	maxHeight += getPaddingTopWithForeground() + getPaddingBottomWithForeground();

	// Check against our minimum height and width
	maxHeight = Math.max(maxHeight, getSuggestedMinimumHeight());
	maxWidth = Math.max(maxWidth, getSuggestedMinimumWidth());

	// Check against our foreground's minimum height and width
	final Drawable drawable = getForeground();
	if (drawable != null) {
	maxHeight = Math.max(maxHeight, drawable.getMinimumHeight());
	maxWidth = Math.max(maxWidth, drawable.getMinimumWidth());
	}

	setMeasuredDimension(resolveSizeAndState(maxWidth, widthMeasureSpec, childState),
	resolveSizeAndState(maxHeight, heightMeasureSpec,
	childState << MEASURED_HEIGHT_STATE_SHIFT));

	if (mListView != null) {
	if (mPendingScroll != 0) {
	mListView.scrollListBy(mPendingScroll);
	mPendingScroll = 0;
	}

	int paddingTop = Math.max(mListView.getPaddingTop(),
	measureAndGetHeight(mTopPanel, widthMeasureSpec, heightMeasureSpec));
	int paddingBottom = Math.max(mListView.getPaddingBottom(),
	measureAndGetHeight(mBottomPanel, widthMeasureSpec, heightMeasureSpec));

	if (paddingTop != mListView.getPaddingTop()
	\|\| paddingBottom != mListView.getPaddingBottom()) {
	mPendingScroll += mListView.getPaddingTop() - paddingTop;
	mListView.setPadding(
	mListView.getPaddingLeft(), paddingTop,
	mListView.getPaddingRight(), paddingBottom);
	}
	}

	count = mMatchParentChildren.size();
	if (count > 1) {
	for (int i = 0; i < count; i++) {
	final View child = mMatchParentChildren.get(i);
	if (mListView == null \|\| (child != mTopPanel && child != mBottomPanel)) {
	applyMeasureToChild(child, widthMeasureSpec, heightMeasureSpec);
	}
	}
	}
	}

	@Override
	public void setForegroundGravity(int foregroundGravity) {
	if (getForegroundGravity() != foregroundGravity) {
	super.setForegroundGravity(foregroundGravity);

	// calling get* again here because the set above may apply default constraints
	final Drawable foreground = getForeground();
	if (getForegroundGravity() == Gravity.FILL && foreground != null) {
	Rect padding = new Rect();
	if (foreground.getPadding(padding)) {
	mForegroundPaddingLeft = padding.left;
	mForegroundPaddingTop = padding.top;
	mForegroundPaddingRight = padding.right;
	mForegroundPaddingBottom = padding.bottom;
	}
	} else {
	mForegroundPaddingLeft = 0;
	mForegroundPaddingTop = 0;
	mForegroundPaddingRight = 0;
	mForegroundPaddingBottom = 0;
	}
	}
	}

	private int getPaddingLeftWithForeground() {
	return isForegroundInsidePadding() ? Math.max(mPaddingLeft, mForegroundPaddingLeft) :
	mPaddingLeft + mForegroundPaddingLeft;
	}

	private int getPaddingRightWithForeground() {
	return isForegroundInsidePadding() ? Math.max(mPaddingRight, mForegroundPaddingRight) :
	mPaddingRight + mForegroundPaddingRight;
	}

	private int getPaddingTopWithForeground() {
	return isForegroundInsidePadding() ? Math.max(mPaddingTop, mForegroundPaddingTop) :
	mPaddingTop + mForegroundPaddingTop;
	}

	private int getPaddingBottomWithForeground() {
	return isForegroundInsidePadding() ? Math.max(mPaddingBottom, mForegroundPaddingBottom) :
	mPaddingBottom + mForegroundPaddingBottom;
	}

	@Override
	public void onScrollChanged() {
	if (mListView == null) {
	return;
	}

	if (mTopPanel != null) {
	if (mListView.getChildCount() > 0) {
	if (mListView.getFirstVisiblePosition() == 0) {
	View firstChild = mListView.getChildAt(0);
	setScrolling(mTopPanel,
	firstChild.getY() - mTopPanel.getHeight() - mTopPanel.getTop());
	} else {
	// shift to hide the frame, last child is not the last position
	setScrolling(mTopPanel, -mTopPanel.getHeight());
	}
	} else {
	setScrolling(mTopPanel, 0); // no visible child, fallback to default behaviour
	}
	}

	if (mBottomPanel != null) {
	if (mListView.getChildCount() > 0) {
	if (mListView.getLastVisiblePosition() >= mListView.getCount() - 1) {
	View lastChild = mListView.getChildAt(mListView.getChildCount() - 1);
	setScrolling(mBottomPanel, Math.max(
	0,
	lastChild.getY() + lastChild.getHeight() - mBottomPanel.getTop()));
	} else {
	// shift to hide the frame, last child is not the last position
	setScrolling(mBottomPanel, mBottomPanel.getHeight());
	}
	} else {
	setScrolling(mBottomPanel, 0); // no visible child, fallback to default behaviour
	}
	}
	}

	/** Only set scrolling for the panel if there is a change in its translationY. */
	private void setScrolling(View panel, float translationY) {
	if (panel.getTranslationY() != translationY) {
	panel.setTranslationY(translationY);
	}
	}
	}