src/com/android/browser/NavTabScroller.java - platform/packages/apps/Browser - Git at Google

 /*
  * Copyright (C) 2011 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.browser;


 import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
 import android.content.Context;
 import android.database.DataSetObserver;
 import android.graphics.Canvas;
 import android.util.AttributeSet;
 import android.view.Gravity;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.animation.DecelerateInterpolator;
 import android.widget.BaseAdapter;
 import android.widget.LinearLayout;

 import com.android.browser.view.ScrollerView;

 /**
  * custom view for displaying tabs in the nav screen
  */
 public class NavTabScroller extends ScrollerView {

     static final int INVALID_POSITION = -1;
     static final float[] PULL_FACTOR = { 2.5f, 0.9f };

     interface OnRemoveListener {
         public void onRemovePosition(int position);
     }

     interface OnLayoutListener {
         public void onLayout(int l, int t, int r, int b);
     }

     private ContentLayout mContentView;
     private BaseAdapter mAdapter;
     private OnRemoveListener mRemoveListener;
     private OnLayoutListener mLayoutListener;
     private int mGap;
     private int mGapPosition;
     private ObjectAnimator mGapAnimator;

     // after drag animation velocity in pixels/sec
     private static final float MIN_VELOCITY = 1500;
     private AnimatorSet mAnimator;

     private float mFlingVelocity;
     private boolean mNeedsScroll;
     private int mScrollPosition;

     DecelerateInterpolator mCubic;
     int mPullValue;

     public NavTabScroller(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
         init(context);
     }

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

     public NavTabScroller(Context context) {
         super(context);
         init(context);
     }

     private void init(Context ctx) {
         mCubic = new DecelerateInterpolator(1.5f);
         mGapPosition = INVALID_POSITION;
         setHorizontalScrollBarEnabled(false);
         setVerticalScrollBarEnabled(false);
         mContentView = new ContentLayout(ctx, this);
         mContentView.setOrientation(LinearLayout.HORIZONTAL);
         addView(mContentView);
         mContentView.setLayoutParams(
                 new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT));
         // ProGuard !
         setGap(getGap());
         mFlingVelocity = getContext().getResources().getDisplayMetrics().density
                 * MIN_VELOCITY;
     }

     protected int getScrollValue() {
         return mHorizontal ? mScrollX : mScrollY;
     }

     protected void setScrollValue(int value) {
         scrollTo(mHorizontal ? value : 0, mHorizontal ? 0 : value);
     }

     protected NavTabView getTabView(int pos) {
         return (NavTabView) mContentView.getChildAt(pos);
     }

     protected boolean isHorizontal() {
         return mHorizontal;
     }

     public void setOrientation(int orientation) {
         mContentView.setOrientation(orientation);
         if (orientation == LinearLayout.HORIZONTAL) {
             mContentView.setLayoutParams(
                     new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT));
         } else {
             mContentView.setLayoutParams(
                     new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
         }
         super.setOrientation(orientation);
     }

     @Override
     protected void onMeasure(int wspec, int hspec) {
         super.onMeasure(wspec, hspec);
         calcPadding();
     }

     private void calcPadding() {
         if (mAdapter.getCount() > 0) {
             View v = mContentView.getChildAt(0);
             if (mHorizontal) {
                 int pad = (getMeasuredWidth() - v.getMeasuredWidth()) / 2 + 2;
                 mContentView.setPadding(pad, 0, pad, 0);
             } else {
                 int pad = (getMeasuredHeight() - v.getMeasuredHeight()) / 2 + 2;
                 mContentView.setPadding(0, pad, 0, pad);
             }
         }
     }

     public void setAdapter(BaseAdapter adapter) {
         setAdapter(adapter, 0);
     }


     public void setOnRemoveListener(OnRemoveListener l) {
         mRemoveListener = l;
     }

     public void setOnLayoutListener(OnLayoutListener l) {
         mLayoutListener = l;
     }

     protected void setAdapter(BaseAdapter adapter, int selection) {
         mAdapter = adapter;
         mAdapter.registerDataSetObserver(new DataSetObserver() {

             @Override
             public void onChanged() {
                 super.onChanged();
                 handleDataChanged();
             }

             @Override
             public void onInvalidated() {
                 super.onInvalidated();
             }
         });
         handleDataChanged(selection);
     }

     protected ViewGroup getContentView() {
         return mContentView;
     }

     protected int getRelativeChildTop(int ix) {
         return mContentView.getChildAt(ix).getTop() - mScrollY;
     }

     protected void handleDataChanged() {
         handleDataChanged(INVALID_POSITION);
     }

     void handleDataChanged(int newscroll) {
         int scroll = getScrollValue();
         if (mGapAnimator != null) {
             mGapAnimator.cancel();
         }
         mContentView.removeAllViews();
         for (int i = 0; i < mAdapter.getCount(); i++) {
             View v = mAdapter.getView(i, null, mContentView);
             LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
                     LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
             lp.gravity = (mHorizontal ? Gravity.CENTER_VERTICAL : Gravity.CENTER_HORIZONTAL);
             mContentView.addView(v, lp);
             if (mGapPosition > INVALID_POSITION){
                 adjustViewGap(v, i);
             }
         }
         if (newscroll > INVALID_POSITION) {
             newscroll = Math.min(mAdapter.getCount() - 1, newscroll);
             mNeedsScroll = true;
             mScrollPosition = newscroll;
             requestLayout();
         } else {
             setScrollValue(scroll);
         }
     }

     protected void finishScroller() {
         mScroller.forceFinished(true);
     }

     @Override
     protected void onLayout(boolean changed, int l, int t, int r, int b) {
         super.onLayout(changed, l, t, r, b);
         if (mNeedsScroll) {
             mScroller.forceFinished(true);
             snapToSelected(mScrollPosition, false);
             mNeedsScroll = false;
         }
         if (mLayoutListener != null) {
             mLayoutListener.onLayout(l, t, r, b);
             mLayoutListener = null;
         }
     }

     void clearTabs() {
         mContentView.removeAllViews();
     }

     void snapToSelected(int pos, boolean smooth) {
         if (pos < 0) return;
         View v = mContentView.getChildAt(pos);
         if (v == null) return;
         int sx = 0;
         int sy = 0;
         if (mHorizontal) {
             sx = (v.getLeft() + v.getRight() - getWidth()) / 2;
         } else {
             sy = (v.getTop() + v.getBottom() - getHeight()) / 2;
         }
         if ((sx != mScrollX) || (sy != mScrollY)) {
             if (smooth) {
                 smoothScrollTo(sx,sy);
             } else {
                 scrollTo(sx, sy);
             }
         }
     }

     protected void animateOut(View v) {
         if (v == null) return;
         animateOut(v, -mFlingVelocity);
     }

     private void animateOut(final View v, float velocity) {
         float start = mHorizontal ? v.getTranslationY() : v.getTranslationX();
         animateOut(v, velocity, start);
     }

     private void animateOut(final View v, float velocity, float start) {
         if ((v == null) || (mAnimator != null)) return;
         final int position = mContentView.indexOfChild(v);
         int target = 0;
         if (velocity < 0) {
             target = mHorizontal ? -getHeight() :  -getWidth();
         } else {
             target = mHorizontal ? getHeight() : getWidth();
         }
         int distance = target - (mHorizontal ? v.getTop() : v.getLeft());
         long duration = (long) (Math.abs(distance) * 1000 / Math.abs(velocity));
         int scroll = 0;
         int translate = 0;
         int gap = mHorizontal ? v.getWidth() : v.getHeight();
         int centerView = getViewCenter(v);
         int centerScreen = getScreenCenter();
         int newpos = INVALID_POSITION;
         if (centerView < centerScreen - gap / 2) {
             // top view
             scroll = - (centerScreen - centerView - gap);
             translate = (position > 0) ? gap : 0;
             newpos = position;
         } else if (centerView > centerScreen + gap / 2) {
             // bottom view
             scroll = - (centerScreen + gap - centerView);
             if (position < mAdapter.getCount() - 1) {
                 translate = -gap;
             }
         } else {
             // center view
             scroll = - (centerScreen - centerView);
             if (position < mAdapter.getCount() - 1) {
                 translate = -gap;
             } else {
                 scroll -= gap;
             }
         }
         mGapPosition = position;
         final int pos = newpos;
         ObjectAnimator trans = ObjectAnimator.ofFloat(v,
                 (mHorizontal ? TRANSLATION_Y : TRANSLATION_X), start, target);
         ObjectAnimator alpha = ObjectAnimator.ofFloat(v, ALPHA, getAlpha(v,start),
                 getAlpha(v,target));
         AnimatorSet set1 = new AnimatorSet();
         set1.playTogether(trans, alpha);
         set1.setDuration(duration);
         mAnimator = new AnimatorSet();
         ObjectAnimator trans2 = null;
         ObjectAnimator scroll1 = null;
         if (scroll != 0) {
             if (mHorizontal) {
                 scroll1 = ObjectAnimator.ofInt(this, "scrollX", getScrollX(), getScrollX() + scroll);
             } else {
                 scroll1 = ObjectAnimator.ofInt(this, "scrollY", getScrollY(), getScrollY() + scroll);
             }
         }
         if (translate != 0) {
             trans2 = ObjectAnimator.ofInt(this, "gap", 0, translate);
         }
         final int duration2 = 200;
         if (scroll1 != null) {
             if (trans2 != null) {
                 AnimatorSet set2 = new AnimatorSet();
                 set2.playTogether(scroll1, trans2);
                 set2.setDuration(duration2);
                 mAnimator.playSequentially(set1, set2);
             } else {
                 scroll1.setDuration(duration2);
                 mAnimator.playSequentially(set1, scroll1);
             }
         } else {
             if (trans2 != null) {
                 trans2.setDuration(duration2);
                 mAnimator.playSequentially(set1, trans2);
             }
         }
         mAnimator.addListener(new AnimatorListenerAdapter() {
             public void onAnimationEnd(Animator a) {
                 if (mRemoveListener !=  null) {
                     mRemoveListener.onRemovePosition(position);
                     mAnimator = null;
                     mGapPosition = INVALID_POSITION;
                     mGap = 0;
                     handleDataChanged(pos);
                 }
             }
         });
         mAnimator.start();
     }

     public void setGap(int gap) {
         if (mGapPosition != INVALID_POSITION) {
             mGap = gap;
             postInvalidate();
         }
     }

     public int getGap() {
         return mGap;
     }

     void adjustGap() {
         for (int i = 0; i < mContentView.getChildCount(); i++) {
             final View child = mContentView.getChildAt(i);
             adjustViewGap(child, i);
         }
     }

     private void adjustViewGap(View view, int pos) {
         if ((mGap < 0 && pos > mGapPosition)
                 || (mGap > 0 && pos < mGapPosition)) {
             if (mHorizontal) {
                 view.setTranslationX(mGap);
             } else {
                 view.setTranslationY(mGap);
             }
         }
     }

     private int getViewCenter(View v) {
         if (mHorizontal) {
             return v.getLeft() + v.getWidth() / 2;
         } else {
             return v.getTop() + v.getHeight() / 2;
         }
     }

     private int getScreenCenter() {
         if (mHorizontal) {
             return getScrollX() + getWidth() / 2;
         } else {
             return getScrollY() + getHeight() / 2;
         }
     }

     @Override
     public void draw(Canvas canvas) {
         if (mGapPosition > INVALID_POSITION) {
             adjustGap();
         }
         super.draw(canvas);
     }

     @Override
     protected View findViewAt(int x, int y) {
         x += mScrollX;
         y += mScrollY;
         final int count = mContentView.getChildCount();
         for (int i = count - 1; i >= 0; i--) {
             View child = mContentView.getChildAt(i);
             if (child.getVisibility() == View.VISIBLE) {
                 if ((x >= child.getLeft()) && (x < child.getRight())
                         && (y >= child.getTop()) && (y < child.getBottom())) {
                     return child;
                 }
             }
         }
         return null;
     }

     @Override
     protected void onOrthoDrag(View v, float distance) {
         if ((v != null) && (mAnimator == null)) {
             offsetView(v, distance);
         }
     }

     @Override
     protected void onOrthoDragFinished(View downView) {
         if (mAnimator != null) return;
         if (mIsOrthoDragged && downView != null) {
             // offset
             float diff = mHorizontal ? downView.getTranslationY() : downView.getTranslationX();
             if (Math.abs(diff) > (mHorizontal ? downView.getHeight() : downView.getWidth()) / 2) {
                 // remove it
                 animateOut(downView, Math.signum(diff) * mFlingVelocity, diff);
             } else {
                 // snap back
                 offsetView(downView, 0);
             }
         }
     }

     @Override
     protected void onOrthoFling(View v, float velocity) {
         if (v == null) return;
         if (mAnimator == null && Math.abs(velocity) > mFlingVelocity / 2) {
             animateOut(v, velocity);
         } else {
             offsetView(v, 0);
         }
     }

     private void offsetView(View v, float distance) {
         v.setAlpha(getAlpha(v, distance));
         if (mHorizontal) {
             v.setTranslationY(distance);
         } else {
             v.setTranslationX(distance);
         }
     }

     private float getAlpha(View v, float distance) {
         return 1 - (float) Math.abs(distance) / (mHorizontal ? v.getHeight() : v.getWidth());
     }

     private float ease(DecelerateInterpolator inter, float value, float start,
             float dist, float duration) {
         return start + dist * inter.getInterpolation(value / duration);
     }

     @Override
     protected void onPull(int delta) {
         boolean layer = false;
         int count = 2;
         if (delta == 0 && mPullValue == 0) return;
         if (delta == 0 && mPullValue != 0) {
             // reset
             for (int i = 0; i < count; i++) {
                 View child = mContentView.getChildAt((mPullValue < 0)
                         ? i
                         : mContentView.getChildCount() - 1 - i);
                 if (child == null) break;
                 ObjectAnimator trans = ObjectAnimator.ofFloat(child,
                         mHorizontal ? "translationX" : "translationY",
                                 mHorizontal ? getTranslationX() : getTranslationY(),
                                 0);
                 ObjectAnimator rot = ObjectAnimator.ofFloat(child,
                         mHorizontal ? "rotationY" : "rotationX",
                                 mHorizontal ? getRotationY() : getRotationX(),
                                 0);
                 AnimatorSet set = new AnimatorSet();
                 set.playTogether(trans, rot);
                 set.setDuration(100);
                 set.start();
             }
             mPullValue = 0;
         } else {
             if (mPullValue == 0) {
                 layer = true;
             }
             mPullValue += delta;
         }
         final int height = mHorizontal ? getWidth() : getHeight();
         int oscroll = Math.abs(mPullValue);
         int factor = (mPullValue <= 0) ? 1 : -1;
         for (int i = 0; i < count; i++) {
             View child = mContentView.getChildAt((mPullValue < 0)
                     ? i
                     : mContentView.getChildCount() - 1 - i);
             if (child == null) break;
             if (layer) {
             }
             float k = PULL_FACTOR[i];
             float rot = -factor * ease(mCubic, oscroll, 0, k * 2, height);
             int y =  factor * (int) ease(mCubic, oscroll, 0, k*20, height);
             if (mHorizontal) {
                 child.setTranslationX(y);
             } else {
                 child.setTranslationY(y);
             }
             if (mHorizontal) {
                 child.setRotationY(-rot);
             } else {
                 child.setRotationX(rot);
             }
         }
     }

     static class ContentLayout extends LinearLayout {

         NavTabScroller mScroller;

         public ContentLayout(Context context, NavTabScroller scroller) {
             super(context);
             mScroller = scroller;
         }

         @Override
         protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
             super.onMeasure(widthMeasureSpec, heightMeasureSpec);
             if (mScroller.getGap() != 0) {
                 View v = getChildAt(0);
                 if (v != null) {
                     if (mScroller.isHorizontal()) {
                         int total = v.getMeasuredWidth() + getMeasuredWidth();
                         setMeasuredDimension(total, getMeasuredHeight());
                     } else {
                         int total = v.getMeasuredHeight() + getMeasuredHeight();
                         setMeasuredDimension(getMeasuredWidth(), total);
                     }
                 }

             }
         }

     }

 }
	/*
	* Copyright (C) 2011 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.browser;


	import android.animation.Animator;
	import android.animation.AnimatorListenerAdapter;
	import android.animation.AnimatorSet;
	import android.animation.ObjectAnimator;
	import android.content.Context;
	import android.database.DataSetObserver;
	import android.graphics.Canvas;
	import android.util.AttributeSet;
	import android.view.Gravity;
	import android.view.View;
	import android.view.ViewGroup;
	import android.view.animation.DecelerateInterpolator;
	import android.widget.BaseAdapter;
	import android.widget.LinearLayout;

	import com.android.browser.view.ScrollerView;

	/**
	* custom view for displaying tabs in the nav screen
	*/
	public class NavTabScroller extends ScrollerView {

	static final int INVALID_POSITION = -1;
	static final float[] PULL_FACTOR = { 2.5f, 0.9f };

	interface OnRemoveListener {
	public void onRemovePosition(int position);
	}

	interface OnLayoutListener {
	public void onLayout(int l, int t, int r, int b);
	}

	private ContentLayout mContentView;
	private BaseAdapter mAdapter;
	private OnRemoveListener mRemoveListener;
	private OnLayoutListener mLayoutListener;
	private int mGap;
	private int mGapPosition;
	private ObjectAnimator mGapAnimator;

	// after drag animation velocity in pixels/sec
	private static final float MIN_VELOCITY = 1500;
	private AnimatorSet mAnimator;

	private float mFlingVelocity;
	private boolean mNeedsScroll;
	private int mScrollPosition;

	DecelerateInterpolator mCubic;
	int mPullValue;

	public NavTabScroller(Context context, AttributeSet attrs, int defStyle) {
	super(context, attrs, defStyle);
	init(context);
	}

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

	public NavTabScroller(Context context) {
	super(context);
	init(context);
	}

	private void init(Context ctx) {
	mCubic = new DecelerateInterpolator(1.5f);
	mGapPosition = INVALID_POSITION;
	setHorizontalScrollBarEnabled(false);
	setVerticalScrollBarEnabled(false);
	mContentView = new ContentLayout(ctx, this);
	mContentView.setOrientation(LinearLayout.HORIZONTAL);
	addView(mContentView);
	mContentView.setLayoutParams(
	new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT));
	// ProGuard !
	setGap(getGap());
	mFlingVelocity = getContext().getResources().getDisplayMetrics().density
	* MIN_VELOCITY;
	}

	protected int getScrollValue() {
	return mHorizontal ? mScrollX : mScrollY;
	}

	protected void setScrollValue(int value) {
	scrollTo(mHorizontal ? value : 0, mHorizontal ? 0 : value);
	}

	protected NavTabView getTabView(int pos) {
	return (NavTabView) mContentView.getChildAt(pos);
	}

	protected boolean isHorizontal() {
	return mHorizontal;
	}

	public void setOrientation(int orientation) {
	mContentView.setOrientation(orientation);
	if (orientation == LinearLayout.HORIZONTAL) {
	mContentView.setLayoutParams(
	new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT));
	} else {
	mContentView.setLayoutParams(
	new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
	}
	super.setOrientation(orientation);
	}

	@Override
	protected void onMeasure(int wspec, int hspec) {
	super.onMeasure(wspec, hspec);
	calcPadding();
	}

	private void calcPadding() {
	if (mAdapter.getCount() > 0) {
	View v = mContentView.getChildAt(0);
	if (mHorizontal) {
	int pad = (getMeasuredWidth() - v.getMeasuredWidth()) / 2 + 2;
	mContentView.setPadding(pad, 0, pad, 0);
	} else {
	int pad = (getMeasuredHeight() - v.getMeasuredHeight()) / 2 + 2;
	mContentView.setPadding(0, pad, 0, pad);
	}
	}
	}

	public void setAdapter(BaseAdapter adapter) {
	setAdapter(adapter, 0);
	}


	public void setOnRemoveListener(OnRemoveListener l) {
	mRemoveListener = l;
	}

	public void setOnLayoutListener(OnLayoutListener l) {
	mLayoutListener = l;
	}

	protected void setAdapter(BaseAdapter adapter, int selection) {
	mAdapter = adapter;
	mAdapter.registerDataSetObserver(new DataSetObserver() {

	@Override
	public void onChanged() {
	super.onChanged();
	handleDataChanged();
	}

	@Override
	public void onInvalidated() {
	super.onInvalidated();
	}
	});
	handleDataChanged(selection);
	}

	protected ViewGroup getContentView() {
	return mContentView;
	}

	protected int getRelativeChildTop(int ix) {
	return mContentView.getChildAt(ix).getTop() - mScrollY;
	}

	protected void handleDataChanged() {
	handleDataChanged(INVALID_POSITION);
	}

	void handleDataChanged(int newscroll) {
	int scroll = getScrollValue();
	if (mGapAnimator != null) {
	mGapAnimator.cancel();
	}
	mContentView.removeAllViews();
	for (int i = 0; i < mAdapter.getCount(); i++) {
	View v = mAdapter.getView(i, null, mContentView);
	LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
	LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
	lp.gravity = (mHorizontal ? Gravity.CENTER_VERTICAL : Gravity.CENTER_HORIZONTAL);
	mContentView.addView(v, lp);
	if (mGapPosition > INVALID_POSITION){
	adjustViewGap(v, i);
	}
	}
	if (newscroll > INVALID_POSITION) {
	newscroll = Math.min(mAdapter.getCount() - 1, newscroll);
	mNeedsScroll = true;
	mScrollPosition = newscroll;
	requestLayout();
	} else {
	setScrollValue(scroll);
	}
	}

	protected void finishScroller() {
	mScroller.forceFinished(true);
	}

	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {
	super.onLayout(changed, l, t, r, b);
	if (mNeedsScroll) {
	mScroller.forceFinished(true);
	snapToSelected(mScrollPosition, false);
	mNeedsScroll = false;
	}
	if (mLayoutListener != null) {
	mLayoutListener.onLayout(l, t, r, b);
	mLayoutListener = null;
	}
	}

	void clearTabs() {
	mContentView.removeAllViews();
	}

	void snapToSelected(int pos, boolean smooth) {
	if (pos < 0) return;
	View v = mContentView.getChildAt(pos);
	if (v == null) return;
	int sx = 0;
	int sy = 0;
	if (mHorizontal) {
	sx = (v.getLeft() + v.getRight() - getWidth()) / 2;
	} else {
	sy = (v.getTop() + v.getBottom() - getHeight()) / 2;
	}
	if ((sx != mScrollX) \|\| (sy != mScrollY)) {
	if (smooth) {
	smoothScrollTo(sx,sy);
	} else {
	scrollTo(sx, sy);
	}
	}
	}

	protected void animateOut(View v) {
	if (v == null) return;
	animateOut(v, -mFlingVelocity);
	}

	private void animateOut(final View v, float velocity) {
	float start = mHorizontal ? v.getTranslationY() : v.getTranslationX();
	animateOut(v, velocity, start);
	}

	private void animateOut(final View v, float velocity, float start) {
	if ((v == null) \|\| (mAnimator != null)) return;
	final int position = mContentView.indexOfChild(v);
	int target = 0;
	if (velocity < 0) {
	target = mHorizontal ? -getHeight() : -getWidth();
	} else {
	target = mHorizontal ? getHeight() : getWidth();
	}
	int distance = target - (mHorizontal ? v.getTop() : v.getLeft());
	long duration = (long) (Math.abs(distance) * 1000 / Math.abs(velocity));
	int scroll = 0;
	int translate = 0;
	int gap = mHorizontal ? v.getWidth() : v.getHeight();
	int centerView = getViewCenter(v);
	int centerScreen = getScreenCenter();
	int newpos = INVALID_POSITION;
	if (centerView < centerScreen - gap / 2) {
	// top view
	scroll = - (centerScreen - centerView - gap);
	translate = (position > 0) ? gap : 0;
	newpos = position;
	} else if (centerView > centerScreen + gap / 2) {
	// bottom view
	scroll = - (centerScreen + gap - centerView);
	if (position < mAdapter.getCount() - 1) {
	translate = -gap;
	}
	} else {
	// center view
	scroll = - (centerScreen - centerView);
	if (position < mAdapter.getCount() - 1) {
	translate = -gap;
	} else {
	scroll -= gap;
	}
	}
	mGapPosition = position;
	final int pos = newpos;
	ObjectAnimator trans = ObjectAnimator.ofFloat(v,
	(mHorizontal ? TRANSLATION_Y : TRANSLATION_X), start, target);
	ObjectAnimator alpha = ObjectAnimator.ofFloat(v, ALPHA, getAlpha(v,start),
	getAlpha(v,target));
	AnimatorSet set1 = new AnimatorSet();
	set1.playTogether(trans, alpha);
	set1.setDuration(duration);
	mAnimator = new AnimatorSet();
	ObjectAnimator trans2 = null;
	ObjectAnimator scroll1 = null;
	if (scroll != 0) {
	if (mHorizontal) {
	scroll1 = ObjectAnimator.ofInt(this, "scrollX", getScrollX(), getScrollX() + scroll);
	} else {
	scroll1 = ObjectAnimator.ofInt(this, "scrollY", getScrollY(), getScrollY() + scroll);
	}
	}
	if (translate != 0) {
	trans2 = ObjectAnimator.ofInt(this, "gap", 0, translate);
	}
	final int duration2 = 200;
	if (scroll1 != null) {
	if (trans2 != null) {
	AnimatorSet set2 = new AnimatorSet();
	set2.playTogether(scroll1, trans2);
	set2.setDuration(duration2);
	mAnimator.playSequentially(set1, set2);
	} else {
	scroll1.setDuration(duration2);
	mAnimator.playSequentially(set1, scroll1);
	}
	} else {
	if (trans2 != null) {
	trans2.setDuration(duration2);
	mAnimator.playSequentially(set1, trans2);
	}
	}
	mAnimator.addListener(new AnimatorListenerAdapter() {
	public void onAnimationEnd(Animator a) {
	if (mRemoveListener != null) {
	mRemoveListener.onRemovePosition(position);
	mAnimator = null;
	mGapPosition = INVALID_POSITION;
	mGap = 0;
	handleDataChanged(pos);
	}
	}
	});
	mAnimator.start();
	}

	public void setGap(int gap) {
	if (mGapPosition != INVALID_POSITION) {
	mGap = gap;
	postInvalidate();
	}
	}

	public int getGap() {
	return mGap;
	}

	void adjustGap() {
	for (int i = 0; i < mContentView.getChildCount(); i++) {
	final View child = mContentView.getChildAt(i);
	adjustViewGap(child, i);
	}
	}

	private void adjustViewGap(View view, int pos) {
	if ((mGap < 0 && pos > mGapPosition)
	\|\| (mGap > 0 && pos < mGapPosition)) {
	if (mHorizontal) {
	view.setTranslationX(mGap);
	} else {
	view.setTranslationY(mGap);
	}
	}
	}

	private int getViewCenter(View v) {
	if (mHorizontal) {
	return v.getLeft() + v.getWidth() / 2;
	} else {
	return v.getTop() + v.getHeight() / 2;
	}
	}

	private int getScreenCenter() {
	if (mHorizontal) {
	return getScrollX() + getWidth() / 2;
	} else {
	return getScrollY() + getHeight() / 2;
	}
	}

	@Override
	public void draw(Canvas canvas) {
	if (mGapPosition > INVALID_POSITION) {
	adjustGap();
	}
	super.draw(canvas);
	}

	@Override
	protected View findViewAt(int x, int y) {
	x += mScrollX;
	y += mScrollY;
	final int count = mContentView.getChildCount();
	for (int i = count - 1; i >= 0; i--) {
	View child = mContentView.getChildAt(i);
	if (child.getVisibility() == View.VISIBLE) {
	if ((x >= child.getLeft()) && (x < child.getRight())
	&& (y >= child.getTop()) && (y < child.getBottom())) {
	return child;
	}
	}
	}
	return null;
	}

	@Override
	protected void onOrthoDrag(View v, float distance) {
	if ((v != null) && (mAnimator == null)) {
	offsetView(v, distance);
	}
	}

	@Override
	protected void onOrthoDragFinished(View downView) {
	if (mAnimator != null) return;
	if (mIsOrthoDragged && downView != null) {
	// offset
	float diff = mHorizontal ? downView.getTranslationY() : downView.getTranslationX();
	if (Math.abs(diff) > (mHorizontal ? downView.getHeight() : downView.getWidth()) / 2) {
	// remove it
	animateOut(downView, Math.signum(diff) * mFlingVelocity, diff);
	} else {
	// snap back
	offsetView(downView, 0);
	}
	}
	}

	@Override
	protected void onOrthoFling(View v, float velocity) {
	if (v == null) return;
	if (mAnimator == null && Math.abs(velocity) > mFlingVelocity / 2) {
	animateOut(v, velocity);
	} else {
	offsetView(v, 0);
	}
	}

	private void offsetView(View v, float distance) {
	v.setAlpha(getAlpha(v, distance));
	if (mHorizontal) {
	v.setTranslationY(distance);
	} else {
	v.setTranslationX(distance);
	}
	}

	private float getAlpha(View v, float distance) {
	return 1 - (float) Math.abs(distance) / (mHorizontal ? v.getHeight() : v.getWidth());
	}

	private float ease(DecelerateInterpolator inter, float value, float start,
	float dist, float duration) {
	return start + dist * inter.getInterpolation(value / duration);
	}

	@Override
	protected void onPull(int delta) {
	boolean layer = false;
	int count = 2;
	if (delta == 0 && mPullValue == 0) return;
	if (delta == 0 && mPullValue != 0) {
	// reset
	for (int i = 0; i < count; i++) {
	View child = mContentView.getChildAt((mPullValue < 0)
	? i
	: mContentView.getChildCount() - 1 - i);
	if (child == null) break;
	ObjectAnimator trans = ObjectAnimator.ofFloat(child,
	mHorizontal ? "translationX" : "translationY",
	mHorizontal ? getTranslationX() : getTranslationY(),
	0);
	ObjectAnimator rot = ObjectAnimator.ofFloat(child,
	mHorizontal ? "rotationY" : "rotationX",
	mHorizontal ? getRotationY() : getRotationX(),
	0);
	AnimatorSet set = new AnimatorSet();
	set.playTogether(trans, rot);
	set.setDuration(100);
	set.start();
	}
	mPullValue = 0;
	} else {
	if (mPullValue == 0) {
	layer = true;
	}
	mPullValue += delta;
	}
	final int height = mHorizontal ? getWidth() : getHeight();
	int oscroll = Math.abs(mPullValue);
	int factor = (mPullValue <= 0) ? 1 : -1;
	for (int i = 0; i < count; i++) {
	View child = mContentView.getChildAt((mPullValue < 0)
	? i
	: mContentView.getChildCount() - 1 - i);
	if (child == null) break;
	if (layer) {
	}
	float k = PULL_FACTOR[i];
	float rot = -factor * ease(mCubic, oscroll, 0, k * 2, height);
	int y = factor * (int) ease(mCubic, oscroll, 0, k*20, height);
	if (mHorizontal) {
	child.setTranslationX(y);
	} else {
	child.setTranslationY(y);
	}
	if (mHorizontal) {
	child.setRotationY(-rot);
	} else {
	child.setRotationX(rot);
	}
	}
	}

	static class ContentLayout extends LinearLayout {

	NavTabScroller mScroller;

	public ContentLayout(Context context, NavTabScroller scroller) {
	super(context);
	mScroller = scroller;
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
	super.onMeasure(widthMeasureSpec, heightMeasureSpec);
	if (mScroller.getGap() != 0) {
	View v = getChildAt(0);
	if (v != null) {
	if (mScroller.isHorizontal()) {
	int total = v.getMeasuredWidth() + getMeasuredWidth();
	setMeasuredDimension(total, getMeasuredHeight());
	} else {
	int total = v.getMeasuredHeight() + getMeasuredHeight();
	setMeasuredDimension(getMeasuredWidth(), total);
	}
	}

	}
	}

	}

	}