chrome/android/java/src/org/chromium/chrome/browser/widget/accessibility/AccessibilityTabModelListItem.java - platform/external/chromium_org - Git at Google

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 package org.chromium.chrome.browser.widget.accessibility;

 import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.os.Handler;
 import android.util.AttributeSet;
 import android.view.GestureDetector;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.ViewGroup;
 import android.widget.AbsListView;
 import android.widget.Button;
 import android.widget.FrameLayout;
 import android.widget.ImageButton;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 import android.widget.TextView;

 import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.EmptyTabObserver;
 import org.chromium.chrome.browser.Tab;
 import org.chromium.chrome.browser.TabObserver;

 /**
  * A widget that shows a single row of the {@link AccessibilityTabModelListView} list.
  * This list shows both the title of the {@link Tab} as well as a close button to close
  * the tab.
  */
 public class AccessibilityTabModelListItem extends FrameLayout implements OnClickListener {
     private static final int CLOSE_ANIMATION_DURATION_MS = 100;
     private static final int DEFAULT_ANIMATION_DURATION_MS = 300;
     private static final int VELOCITY_SCALING_FACTOR = 150;
     private static final int CLOSE_TIMEOUT_MS = 2000;

     private int mCloseAnimationDurationMs;
     private int mDefaultAnimationDurationMs;
     private int mCloseTimeoutMs;
     // The last run animation (if non-null, it still might have already completed).
     private Animator mActiveAnimation;

     private final float mSwipeCommitDistance;
     private final float mFlingCommitDistance;

     // Keeps track of how a tab was closed
     //  < 0 : swiped to the left.
     //  > 0 : swiped to the right.
     //  = 0 : closed with the close button.
     private float mSwipedAway;

     // The children on the standard view.
     private LinearLayout mTabContents;
     private TextView mTitleView;
     private ImageView mFaviconView;
     private ImageButton mCloseButton;

     // The children on the undo view.
     private LinearLayout mUndoContents;
     private Button mUndoButton;

     private Tab mTab;
     private boolean mCanUndo;
     private AccessibilityTabModelListItemListener mListener;
     private final GestureDetector mSwipeGestureDetector;
     private final int mDefaultHeight;
     private AccessibilityTabModelListView mCanScrollListener;

     /**
      * An interface that exposes actions taken on this item.  The registered listener will be
      * sent selection and close events based on user input.
      */
     public interface AccessibilityTabModelListItemListener {
         /**
          * Called when a user clicks on this list item.
          * @param tabId The ID of the tab that this list item represents.
          */
         public void tabSelected(int tabId);

         /**
          * Called when a user clicks on the close button of this list item.
          * @param tabId The ID of the tab that this list item represents.
          */
         public void tabClosed(int tabId);

         /**
          * Called when the data corresponding to this list item has changed.
          * @param tabId The ID of the tab that this list item represents.
          */
         public void tabChanged(int tabId);

         /**
          * @return Whether or not the tab is scheduled to be closed.
          */
         public boolean hasPendingClosure(int tabId);

         /**
          * Schedule a tab to be closed in the future.
          * @param tabId The ID of the tab to close.
          */
         public void schedulePendingClosure(int tabId);

         /**
          * Cancel a tab's closure.
          * @param tabId The ID of the tab that should no longer be closed.
          */
         public void cancelPendingClosure(int tabId);
     }

     private final Runnable mCloseRunnable = new Runnable() {
         @Override
         public void run() {
             runCloseAnimation();
         }
     };

     private final Handler mHandler = new Handler();

     /**
      * Used with the swipe away and blink out animations to bring in the undo view.
      */
     private final AnimatorListenerAdapter mCloseAnimatorListener =
             new AnimatorListenerAdapter() {
         private boolean mIsCancelled;

         @Override
         public void onAnimationStart(Animator animation) {
             mIsCancelled = false;
         }

         @Override
         public void onAnimationCancel(Animator animation) {
             mIsCancelled = true;
         }

         @Override
         public void onAnimationEnd(Animator animator) {
             if (mIsCancelled) return;

             mListener.schedulePendingClosure(mTab.getId());
             setTranslationX(0.f);
             setScaleX(1.f);
             setScaleY(1.f);
             setAlpha(0.f);
             showUndoView(true);
             runResetAnimation(false);
             mHandler.postDelayed(mCloseRunnable, mCloseTimeoutMs);
         }
     };

     /**
      * Used with the close animation to actually close a tab after it has shrunk away.
      */
     private final AnimatorListenerAdapter mActuallyCloseAnimatorListener =
             new AnimatorListenerAdapter() {
         private boolean mIsCancelled;

         @Override
         public void onAnimationStart(Animator animation) {
             mIsCancelled = false;
         }

         @Override
         public void onAnimationCancel(Animator animation) {
             mIsCancelled = true;
         }

         @Override
         public void onAnimationEnd(Animator animator) {
             if (mIsCancelled) return;

             showUndoView(false);
             setAlpha(1.f);
             mTabContents.setAlpha(1.f);
             mUndoContents.setAlpha(1.f);
             cancelRunningAnimation();
             mListener.tabClosed(mTab.getId());
         }
     };

     /**
      * @param context The Context to build this widget in.
      * @param attrs The AttributeSet to use to build this widget.
      */
     public AccessibilityTabModelListItem(Context context, AttributeSet attrs) {
         super(context, attrs);
         mSwipeGestureDetector = new GestureDetector(context, new SwipeGestureListener());
         mSwipeCommitDistance =
                 context.getResources().getDimension(R.dimen.swipe_commit_distance);
         mFlingCommitDistance = mSwipeCommitDistance / 3;

         mDefaultHeight =
                 context.getResources().getDimensionPixelOffset(R.dimen.accessibility_tab_height);

         mCloseAnimationDurationMs = CLOSE_ANIMATION_DURATION_MS;
         mDefaultAnimationDurationMs = DEFAULT_ANIMATION_DURATION_MS;
         mCloseTimeoutMs = CLOSE_TIMEOUT_MS;
     }

     @Override
     public void onFinishInflate() {
         super.onFinishInflate();
         mTabContents = (LinearLayout) findViewById(R.id.tab_contents);
         mTitleView = (TextView) findViewById(R.id.tab_title);
         mFaviconView = (ImageView) findViewById(R.id.tab_favicon);
         mCloseButton = (ImageButton) findViewById(R.id.close_btn);

         mUndoContents = (LinearLayout) findViewById(R.id.undo_contents);
         mUndoButton = (Button) findViewById(R.id.undo_button);

         setClickable(true);
         setFocusable(true);

         mCloseButton.setOnClickListener(this);
         mUndoButton.setOnClickListener(this);
         setOnClickListener(this);
     }

     /**
      * Sets the {@link Tab} this {@link View} will represent in the list.
      * @param tab     The {@link Tab} to represent.
      * @param canUndo Whether or not closing this {@link Tab} can be undone.
      */
     public void setTab(Tab tab, boolean canUndo) {
         if (mTab != null) mTab.removeObserver(mTabObserver);
         mTab = tab;
         tab.addObserver(mTabObserver);
         mCanUndo = canUndo;
         updateTabTitle();
         updateFavicon();
     }

     private void showUndoView(boolean showView) {
         if (showView && mCanUndo) {
             mUndoContents.setVisibility(View.VISIBLE);
             mTabContents.setVisibility(View.INVISIBLE);
         } else {
             mTabContents.setVisibility(View.VISIBLE);
             mUndoContents.setVisibility(View.INVISIBLE);
             updateTabTitle();
             updateFavicon();
         }
     }

     /**
      * Registers a listener to be notified of selection and close events taken on this list item.
      * @param listener The listener to be notified of selection and close events.
      */
     public void setListeners(AccessibilityTabModelListItemListener listener,
             AccessibilityTabModelListView canScrollListener) {
         mListener = listener;
         mCanScrollListener = canScrollListener;
     }

     private void updateTabTitle() {
         String title = mTab != null ? mTab.getTitle() : null;
         if (title == null || title.isEmpty()) {
             title = getContext().getResources().getString(R.string.tab_loading_default_title);
         }

         if (!title.equals(mTitleView.getText())) mTitleView.setText(title);

         String accessibilityString = getContext().getString(R.string.accessibility_tabstrip_tab,
                 title);
         if (!accessibilityString.equals(getContentDescription())) {
             setContentDescription(getContext().getString(R.string.accessibility_tabstrip_tab,
                     title));
         }
     }

     private void updateFavicon() {
         if (mTab != null) {
             Bitmap bitmap = mTab.getFavicon();
             if (bitmap != null) {
                 mFaviconView.setImageBitmap(bitmap);
             } else {
                 mFaviconView.setImageResource(R.drawable.globe_incognito_favicon);
             }
         }
     }

     @Override
     public void onClick(View v) {
         if (mListener == null) return;

         int tabId = mTab.getId();
         if (v == AccessibilityTabModelListItem.this && !mListener.hasPendingClosure(tabId)) {
             mListener.tabSelected(tabId);
         } else if (v == mCloseButton) {
             if (mCanUndo) {
                 runBlinkOutAnimation();
             } else {
                 runCloseAnimation();
             }
         } else if (v == mUndoButton) {
             // Kill the close action.
             mHandler.removeCallbacks(mCloseRunnable);

             mListener.cancelPendingClosure(tabId);
             showUndoView(false);
             setAlpha(0.f);
             if (mSwipedAway > 0.f) {
                 setTranslationX(getWidth());
                 runResetAnimation(false);
             } else if (mSwipedAway < 0.f) {
                 setTranslationX(-getWidth());
                 runResetAnimation(false);
             } else {
                 setScaleX(1.2f);
                 setScaleY(0.f);
                 runResetAnimation(true);
             }
         }
     }

     @Override
     protected void onDetachedFromWindow() {
         super.onDetachedFromWindow();
         if (mTab != null) mTab.removeObserver(mTabObserver);
         cancelRunningAnimation();
     }

     private final TabObserver mTabObserver = new EmptyTabObserver() {
         @Override
         public void onFaviconUpdated(Tab tab) {
             updateFavicon();
             notifyTabUpdated(tab);
         }

         @Override
         public void onTitleUpdated(Tab tab) {
             updateTabTitle();
             notifyTabUpdated(tab);
         }

         @Override
         public void onUrlUpdated(Tab tab) {
             updateTabTitle();
             notifyTabUpdated(tab);
         }
     };

     @Override
     public boolean onTouchEvent(MotionEvent e) {
         // If there is a pending close task, remove it.
         mHandler.removeCallbacks(mCloseRunnable);

         boolean handled = mSwipeGestureDetector.onTouchEvent(e);
         if (handled) return true;
         if (e.getActionMasked() == MotionEvent.ACTION_UP) {
             if (Math.abs(getTranslationX()) > mSwipeCommitDistance) {
                 runSwipeAnimation(DEFAULT_ANIMATION_DURATION_MS);
             } else {
                 runResetAnimation(false);
             }
             mCanScrollListener.setCanScroll(true);
             return true;
         }
         return super.onTouchEvent(e);
     }

     /**
      * This call is exposed for the benefit of the animators.
      *
      * @param height The height of the current view.
      */
     public void setHeight(int height) {
         AbsListView.LayoutParams params = (AbsListView.LayoutParams) getLayoutParams();
         if (params == null) {
             params = new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, height);
         } else {
             if (params.height == height) return;
             params.height = height;
         }
         setLayoutParams(params);
     }

     /**
      * Used to reset the state because views are recycled.
      */
     public void resetState() {
         setTranslationX(0.f);
         setAlpha(1.f);
         setScaleX(1.f);
         setScaleY(1.f);
         setHeight(mDefaultHeight);
         cancelRunningAnimation();
         // Remove any callbacks.
         mHandler.removeCallbacks(mCloseRunnable);

         if (mListener != null) {
             boolean hasPendingClosure = mListener.hasPendingClosure(mTab.getId());
             showUndoView(hasPendingClosure);
             if (hasPendingClosure) mHandler.postDelayed(mCloseRunnable, mCloseTimeoutMs);
         } else {
             showUndoView(false);
         }
     }

     /**
      * Simple gesture listener to catch the scroll and fling gestures on the list item.
      */
     private class SwipeGestureListener extends GestureDetector.SimpleOnGestureListener {
         @Override
         public boolean onDown(MotionEvent e) {
             // Returns true so that we can handle events that start with an onDown.
             return true;
         }

         @Override
         public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
             // Don't scroll if we're waiting for user interaction.
             if (mListener.hasPendingClosure(mTab.getId())) return false;

             // Stop the ListView from scrolling vertically.
             mCanScrollListener.setCanScroll(false);

             float distance = e2.getX() - e1.getX();
             setTranslationX(distance + getTranslationX());
             setAlpha(1 - Math.abs(getTranslationX() / getWidth()));
             return true;
         }

         @Override
         public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
             // Arbitrary threshold that feels right.
             if (Math.abs(getTranslationX()) < mFlingCommitDistance) return false;

             double velocityMagnitude = Math.sqrt(velocityX * velocityX + velocityY * velocityY);
             long closeTime = (long) Math.abs((getWidth() / velocityMagnitude)) *
                     VELOCITY_SCALING_FACTOR;
             runSwipeAnimation(Math.min(closeTime, mDefaultAnimationDurationMs));
             mCanScrollListener.setCanScroll(true);
             return true;
         }

         @Override
         public boolean onSingleTapConfirmed(MotionEvent e) {
             performClick();
             return true;
         }
     }

     @VisibleForTesting
     public void disableAnimations() {
         mCloseAnimationDurationMs = 0;
         mDefaultAnimationDurationMs = 0;
         mCloseTimeoutMs = 0;
     }

     @VisibleForTesting
     public boolean hasPendingClosure() {
         if (mListener != null) return mListener.hasPendingClosure(mTab.getId());
         return false;
     }

     private void runSwipeAnimation(long time) {
         cancelRunningAnimation();
         mSwipedAway = getTranslationX();

         ObjectAnimator swipe = ObjectAnimator.ofFloat(this, View.TRANSLATION_X,
                 getTranslationX() > 0 ? getWidth() : -getWidth());
         ObjectAnimator fadeOut = ObjectAnimator.ofFloat(this, View.ALPHA, 0.f);

         AnimatorSet set = new AnimatorSet();
         set.playTogether(fadeOut, swipe);
         set.addListener(mCloseAnimatorListener);
         set.setDuration(Math.min(time, mDefaultAnimationDurationMs));
         set.start();

         mActiveAnimation = set;
     }

     private void runResetAnimation(boolean useCloseAnimationDuration) {
         cancelRunningAnimation();

         ObjectAnimator swipe = ObjectAnimator.ofFloat(this, View.TRANSLATION_X, 0.f);
         ObjectAnimator fadeIn = ObjectAnimator.ofFloat(this, View.ALPHA, 1.f);
         ObjectAnimator scaleX = ObjectAnimator.ofFloat(this, View.SCALE_X, 1.f);
         ObjectAnimator scaleY = ObjectAnimator.ofFloat(this, View.SCALE_Y, 1.f);
         ObjectAnimator resetHeight = ObjectAnimator.ofInt(this, "height", mDefaultHeight);

         AnimatorSet set = new AnimatorSet();
         set.playTogether(swipe, fadeIn, scaleX, scaleY, resetHeight);
         set.setDuration(useCloseAnimationDuration
                 ? mCloseAnimationDurationMs : mDefaultAnimationDurationMs);
         set.start();

         mActiveAnimation = set;
     }

     private void runBlinkOutAnimation() {
         cancelRunningAnimation();
         mSwipedAway = 0;

         ObjectAnimator stretchX = ObjectAnimator.ofFloat(this, View.SCALE_X, 1.2f);
         ObjectAnimator shrinkY = ObjectAnimator.ofFloat(this, View.SCALE_Y, 0.f);
         ObjectAnimator fadeOut = ObjectAnimator.ofFloat(this, View.ALPHA, 0.f);

         AnimatorSet set = new AnimatorSet();
         set.playTogether(fadeOut, shrinkY, stretchX);
         set.addListener(mCloseAnimatorListener);
         set.setDuration(mCloseAnimationDurationMs);
         set.start();

         mActiveAnimation = set;
     }

     private void runCloseAnimation() {
         cancelRunningAnimation();

         ObjectAnimator shrinkHeight = ObjectAnimator.ofInt(this, "height", 0);
         ObjectAnimator shrinkY = ObjectAnimator.ofFloat(this, View.SCALE_Y, 0.f);

         AnimatorSet set = new AnimatorSet();
         set.playTogether(shrinkHeight, shrinkY);
         set.addListener(mActuallyCloseAnimatorListener);
         set.setDuration(mDefaultAnimationDurationMs);
         set.start();

         mActiveAnimation = set;
     }

     private void cancelRunningAnimation() {
         if (mActiveAnimation != null && mActiveAnimation.isRunning()) mActiveAnimation.cancel();

         mActiveAnimation = null;
     }

     private void notifyTabUpdated(Tab tab) {
         if (mListener != null) mListener.tabChanged(tab.getId());
     }
 }
	// Copyright 2014 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	package org.chromium.chrome.browser.widget.accessibility;

	import android.animation.Animator;
	import android.animation.AnimatorListenerAdapter;
	import android.animation.AnimatorSet;
	import android.animation.ObjectAnimator;
	import android.content.Context;
	import android.graphics.Bitmap;
	import android.os.Handler;
	import android.util.AttributeSet;
	import android.view.GestureDetector;
	import android.view.MotionEvent;
	import android.view.View;
	import android.view.View.OnClickListener;
	import android.view.ViewGroup;
	import android.widget.AbsListView;
	import android.widget.Button;
	import android.widget.FrameLayout;
	import android.widget.ImageButton;
	import android.widget.ImageView;
	import android.widget.LinearLayout;
	import android.widget.TextView;

	import org.chromium.base.VisibleForTesting;
	import org.chromium.chrome.R;
	import org.chromium.chrome.browser.EmptyTabObserver;
	import org.chromium.chrome.browser.Tab;
	import org.chromium.chrome.browser.TabObserver;

	/**
	* A widget that shows a single row of the {@link AccessibilityTabModelListView} list.
	* This list shows both the title of the {@link Tab} as well as a close button to close
	* the tab.
	*/
	public class AccessibilityTabModelListItem extends FrameLayout implements OnClickListener {
	private static final int CLOSE_ANIMATION_DURATION_MS = 100;
	private static final int DEFAULT_ANIMATION_DURATION_MS = 300;
	private static final int VELOCITY_SCALING_FACTOR = 150;
	private static final int CLOSE_TIMEOUT_MS = 2000;

	private int mCloseAnimationDurationMs;
	private int mDefaultAnimationDurationMs;
	private int mCloseTimeoutMs;
	// The last run animation (if non-null, it still might have already completed).
	private Animator mActiveAnimation;

	private final float mSwipeCommitDistance;
	private final float mFlingCommitDistance;

	// Keeps track of how a tab was closed
	// < 0 : swiped to the left.
	// > 0 : swiped to the right.
	// = 0 : closed with the close button.
	private float mSwipedAway;

	// The children on the standard view.
	private LinearLayout mTabContents;
	private TextView mTitleView;
	private ImageView mFaviconView;
	private ImageButton mCloseButton;

	// The children on the undo view.
	private LinearLayout mUndoContents;
	private Button mUndoButton;

	private Tab mTab;
	private boolean mCanUndo;
	private AccessibilityTabModelListItemListener mListener;
	private final GestureDetector mSwipeGestureDetector;
	private final int mDefaultHeight;
	private AccessibilityTabModelListView mCanScrollListener;

	/**
	* An interface that exposes actions taken on this item. The registered listener will be
	* sent selection and close events based on user input.
	*/
	public interface AccessibilityTabModelListItemListener {
	/**
	* Called when a user clicks on this list item.
	* @param tabId The ID of the tab that this list item represents.
	*/
	public void tabSelected(int tabId);

	/**
	* Called when a user clicks on the close button of this list item.
	* @param tabId The ID of the tab that this list item represents.
	*/
	public void tabClosed(int tabId);

	/**
	* Called when the data corresponding to this list item has changed.
	* @param tabId The ID of the tab that this list item represents.
	*/
	public void tabChanged(int tabId);

	/**
	* @return Whether or not the tab is scheduled to be closed.
	*/
	public boolean hasPendingClosure(int tabId);

	/**
	* Schedule a tab to be closed in the future.
	* @param tabId The ID of the tab to close.
	*/
	public void schedulePendingClosure(int tabId);

	/**
	* Cancel a tab's closure.
	* @param tabId The ID of the tab that should no longer be closed.
	*/
	public void cancelPendingClosure(int tabId);
	}

	private final Runnable mCloseRunnable = new Runnable() {
	@Override
	public void run() {
	runCloseAnimation();
	}
	};

	private final Handler mHandler = new Handler();

	/**
	* Used with the swipe away and blink out animations to bring in the undo view.
	*/
	private final AnimatorListenerAdapter mCloseAnimatorListener =
	new AnimatorListenerAdapter() {
	private boolean mIsCancelled;

	@Override
	public void onAnimationStart(Animator animation) {
	mIsCancelled = false;
	}

	@Override
	public void onAnimationCancel(Animator animation) {
	mIsCancelled = true;
	}

	@Override
	public void onAnimationEnd(Animator animator) {
	if (mIsCancelled) return;

	mListener.schedulePendingClosure(mTab.getId());
	setTranslationX(0.f);
	setScaleX(1.f);
	setScaleY(1.f);
	setAlpha(0.f);
	showUndoView(true);
	runResetAnimation(false);
	mHandler.postDelayed(mCloseRunnable, mCloseTimeoutMs);
	}
	};

	/**
	* Used with the close animation to actually close a tab after it has shrunk away.
	*/
	private final AnimatorListenerAdapter mActuallyCloseAnimatorListener =
	new AnimatorListenerAdapter() {
	private boolean mIsCancelled;

	@Override
	public void onAnimationStart(Animator animation) {
	mIsCancelled = false;
	}

	@Override
	public void onAnimationCancel(Animator animation) {
	mIsCancelled = true;
	}

	@Override
	public void onAnimationEnd(Animator animator) {
	if (mIsCancelled) return;

	showUndoView(false);
	setAlpha(1.f);
	mTabContents.setAlpha(1.f);
	mUndoContents.setAlpha(1.f);
	cancelRunningAnimation();
	mListener.tabClosed(mTab.getId());
	}
	};

	/**
	* @param context The Context to build this widget in.
	* @param attrs The AttributeSet to use to build this widget.
	*/
	public AccessibilityTabModelListItem(Context context, AttributeSet attrs) {
	super(context, attrs);
	mSwipeGestureDetector = new GestureDetector(context, new SwipeGestureListener());
	mSwipeCommitDistance =
	context.getResources().getDimension(R.dimen.swipe_commit_distance);
	mFlingCommitDistance = mSwipeCommitDistance / 3;

	mDefaultHeight =
	context.getResources().getDimensionPixelOffset(R.dimen.accessibility_tab_height);

	mCloseAnimationDurationMs = CLOSE_ANIMATION_DURATION_MS;
	mDefaultAnimationDurationMs = DEFAULT_ANIMATION_DURATION_MS;
	mCloseTimeoutMs = CLOSE_TIMEOUT_MS;
	}

	@Override
	public void onFinishInflate() {
	super.onFinishInflate();
	mTabContents = (LinearLayout) findViewById(R.id.tab_contents);
	mTitleView = (TextView) findViewById(R.id.tab_title);
	mFaviconView = (ImageView) findViewById(R.id.tab_favicon);
	mCloseButton = (ImageButton) findViewById(R.id.close_btn);

	mUndoContents = (LinearLayout) findViewById(R.id.undo_contents);
	mUndoButton = (Button) findViewById(R.id.undo_button);

	setClickable(true);
	setFocusable(true);

	mCloseButton.setOnClickListener(this);
	mUndoButton.setOnClickListener(this);
	setOnClickListener(this);
	}

	/**
	* Sets the {@link Tab} this {@link View} will represent in the list.
	* @param tab The {@link Tab} to represent.
	* @param canUndo Whether or not closing this {@link Tab} can be undone.
	*/
	public void setTab(Tab tab, boolean canUndo) {
	if (mTab != null) mTab.removeObserver(mTabObserver);
	mTab = tab;
	tab.addObserver(mTabObserver);
	mCanUndo = canUndo;
	updateTabTitle();
	updateFavicon();
	}

	private void showUndoView(boolean showView) {
	if (showView && mCanUndo) {
	mUndoContents.setVisibility(View.VISIBLE);
	mTabContents.setVisibility(View.INVISIBLE);
	} else {
	mTabContents.setVisibility(View.VISIBLE);
	mUndoContents.setVisibility(View.INVISIBLE);
	updateTabTitle();
	updateFavicon();
	}
	}

	/**
	* Registers a listener to be notified of selection and close events taken on this list item.
	* @param listener The listener to be notified of selection and close events.
	*/
	public void setListeners(AccessibilityTabModelListItemListener listener,
	AccessibilityTabModelListView canScrollListener) {
	mListener = listener;
	mCanScrollListener = canScrollListener;
	}

	private void updateTabTitle() {
	String title = mTab != null ? mTab.getTitle() : null;
	if (title == null \|\| title.isEmpty()) {
	title = getContext().getResources().getString(R.string.tab_loading_default_title);
	}

	if (!title.equals(mTitleView.getText())) mTitleView.setText(title);

	String accessibilityString = getContext().getString(R.string.accessibility_tabstrip_tab,
	title);
	if (!accessibilityString.equals(getContentDescription())) {
	setContentDescription(getContext().getString(R.string.accessibility_tabstrip_tab,
	title));
	}
	}

	private void updateFavicon() {
	if (mTab != null) {
	Bitmap bitmap = mTab.getFavicon();
	if (bitmap != null) {
	mFaviconView.setImageBitmap(bitmap);
	} else {
	mFaviconView.setImageResource(R.drawable.globe_incognito_favicon);
	}
	}
	}

	@Override
	public void onClick(View v) {
	if (mListener == null) return;

	int tabId = mTab.getId();
	if (v == AccessibilityTabModelListItem.this && !mListener.hasPendingClosure(tabId)) {
	mListener.tabSelected(tabId);
	} else if (v == mCloseButton) {
	if (mCanUndo) {
	runBlinkOutAnimation();
	} else {
	runCloseAnimation();
	}
	} else if (v == mUndoButton) {
	// Kill the close action.
	mHandler.removeCallbacks(mCloseRunnable);

	mListener.cancelPendingClosure(tabId);
	showUndoView(false);
	setAlpha(0.f);
	if (mSwipedAway > 0.f) {
	setTranslationX(getWidth());
	runResetAnimation(false);
	} else if (mSwipedAway < 0.f) {
	setTranslationX(-getWidth());
	runResetAnimation(false);
	} else {
	setScaleX(1.2f);
	setScaleY(0.f);
	runResetAnimation(true);
	}
	}
	}

	@Override
	protected void onDetachedFromWindow() {
	super.onDetachedFromWindow();
	if (mTab != null) mTab.removeObserver(mTabObserver);
	cancelRunningAnimation();
	}

	private final TabObserver mTabObserver = new EmptyTabObserver() {
	@Override
	public void onFaviconUpdated(Tab tab) {
	updateFavicon();
	notifyTabUpdated(tab);
	}

	@Override
	public void onTitleUpdated(Tab tab) {
	updateTabTitle();
	notifyTabUpdated(tab);
	}

	@Override
	public void onUrlUpdated(Tab tab) {
	updateTabTitle();
	notifyTabUpdated(tab);
	}
	};

	@Override
	public boolean onTouchEvent(MotionEvent e) {
	// If there is a pending close task, remove it.
	mHandler.removeCallbacks(mCloseRunnable);

	boolean handled = mSwipeGestureDetector.onTouchEvent(e);
	if (handled) return true;
	if (e.getActionMasked() == MotionEvent.ACTION_UP) {
	if (Math.abs(getTranslationX()) > mSwipeCommitDistance) {
	runSwipeAnimation(DEFAULT_ANIMATION_DURATION_MS);
	} else {
	runResetAnimation(false);
	}
	mCanScrollListener.setCanScroll(true);
	return true;
	}
	return super.onTouchEvent(e);
	}

	/**
	* This call is exposed for the benefit of the animators.
	*
	* @param height The height of the current view.
	*/
	public void setHeight(int height) {
	AbsListView.LayoutParams params = (AbsListView.LayoutParams) getLayoutParams();
	if (params == null) {
	params = new AbsListView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, height);
	} else {
	if (params.height == height) return;
	params.height = height;
	}
	setLayoutParams(params);
	}

	/**
	* Used to reset the state because views are recycled.
	*/
	public void resetState() {
	setTranslationX(0.f);
	setAlpha(1.f);
	setScaleX(1.f);
	setScaleY(1.f);
	setHeight(mDefaultHeight);
	cancelRunningAnimation();
	// Remove any callbacks.
	mHandler.removeCallbacks(mCloseRunnable);

	if (mListener != null) {
	boolean hasPendingClosure = mListener.hasPendingClosure(mTab.getId());
	showUndoView(hasPendingClosure);
	if (hasPendingClosure) mHandler.postDelayed(mCloseRunnable, mCloseTimeoutMs);
	} else {
	showUndoView(false);
	}
	}

	/**
	* Simple gesture listener to catch the scroll and fling gestures on the list item.
	*/
	private class SwipeGestureListener extends GestureDetector.SimpleOnGestureListener {
	@Override
	public boolean onDown(MotionEvent e) {
	// Returns true so that we can handle events that start with an onDown.
	return true;
	}

	@Override
	public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
	// Don't scroll if we're waiting for user interaction.
	if (mListener.hasPendingClosure(mTab.getId())) return false;

	// Stop the ListView from scrolling vertically.
	mCanScrollListener.setCanScroll(false);

	float distance = e2.getX() - e1.getX();
	setTranslationX(distance + getTranslationX());
	setAlpha(1 - Math.abs(getTranslationX() / getWidth()));
	return true;
	}

	@Override
	public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
	// Arbitrary threshold that feels right.
	if (Math.abs(getTranslationX()) < mFlingCommitDistance) return false;

	double velocityMagnitude = Math.sqrt(velocityX * velocityX + velocityY * velocityY);
	long closeTime = (long) Math.abs((getWidth() / velocityMagnitude)) *
	VELOCITY_SCALING_FACTOR;
	runSwipeAnimation(Math.min(closeTime, mDefaultAnimationDurationMs));
	mCanScrollListener.setCanScroll(true);
	return true;
	}

	@Override
	public boolean onSingleTapConfirmed(MotionEvent e) {
	performClick();
	return true;
	}
	}

	@VisibleForTesting
	public void disableAnimations() {
	mCloseAnimationDurationMs = 0;
	mDefaultAnimationDurationMs = 0;
	mCloseTimeoutMs = 0;
	}

	@VisibleForTesting
	public boolean hasPendingClosure() {
	if (mListener != null) return mListener.hasPendingClosure(mTab.getId());
	return false;
	}

	private void runSwipeAnimation(long time) {
	cancelRunningAnimation();
	mSwipedAway = getTranslationX();

	ObjectAnimator swipe = ObjectAnimator.ofFloat(this, View.TRANSLATION_X,
	getTranslationX() > 0 ? getWidth() : -getWidth());
	ObjectAnimator fadeOut = ObjectAnimator.ofFloat(this, View.ALPHA, 0.f);

	AnimatorSet set = new AnimatorSet();
	set.playTogether(fadeOut, swipe);
	set.addListener(mCloseAnimatorListener);
	set.setDuration(Math.min(time, mDefaultAnimationDurationMs));
	set.start();

	mActiveAnimation = set;
	}

	private void runResetAnimation(boolean useCloseAnimationDuration) {
	cancelRunningAnimation();

	ObjectAnimator swipe = ObjectAnimator.ofFloat(this, View.TRANSLATION_X, 0.f);
	ObjectAnimator fadeIn = ObjectAnimator.ofFloat(this, View.ALPHA, 1.f);
	ObjectAnimator scaleX = ObjectAnimator.ofFloat(this, View.SCALE_X, 1.f);
	ObjectAnimator scaleY = ObjectAnimator.ofFloat(this, View.SCALE_Y, 1.f);
	ObjectAnimator resetHeight = ObjectAnimator.ofInt(this, "height", mDefaultHeight);

	AnimatorSet set = new AnimatorSet();
	set.playTogether(swipe, fadeIn, scaleX, scaleY, resetHeight);
	set.setDuration(useCloseAnimationDuration
	? mCloseAnimationDurationMs : mDefaultAnimationDurationMs);
	set.start();

	mActiveAnimation = set;
	}

	private void runBlinkOutAnimation() {
	cancelRunningAnimation();
	mSwipedAway = 0;

	ObjectAnimator stretchX = ObjectAnimator.ofFloat(this, View.SCALE_X, 1.2f);
	ObjectAnimator shrinkY = ObjectAnimator.ofFloat(this, View.SCALE_Y, 0.f);
	ObjectAnimator fadeOut = ObjectAnimator.ofFloat(this, View.ALPHA, 0.f);

	AnimatorSet set = new AnimatorSet();
	set.playTogether(fadeOut, shrinkY, stretchX);
	set.addListener(mCloseAnimatorListener);
	set.setDuration(mCloseAnimationDurationMs);
	set.start();

	mActiveAnimation = set;
	}

	private void runCloseAnimation() {
	cancelRunningAnimation();

	ObjectAnimator shrinkHeight = ObjectAnimator.ofInt(this, "height", 0);
	ObjectAnimator shrinkY = ObjectAnimator.ofFloat(this, View.SCALE_Y, 0.f);

	AnimatorSet set = new AnimatorSet();
	set.playTogether(shrinkHeight, shrinkY);
	set.addListener(mActuallyCloseAnimatorListener);
	set.setDuration(mDefaultAnimationDurationMs);
	set.start();

	mActiveAnimation = set;
	}

	private void cancelRunningAnimation() {
	if (mActiveAnimation != null && mActiveAnimation.isRunning()) mActiveAnimation.cancel();

	mActiveAnimation = null;
	}

	private void notifyTabUpdated(Tab tab) {
	if (mListener != null) mListener.tabChanged(tab.getId());
	}
	}