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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.tv.settings.widget;
     18 
     19 import android.animation.Animator;
     20 import android.animation.AnimatorSet;
     21 import android.animation.ValueAnimator;
     22 import android.content.Context;
     23 import android.util.DisplayMetrics;
     24 import android.util.TypedValue;
     25 import android.view.View;
     26 
     27 import java.util.ArrayList;
     28 
     29 /**
     30  * SimpleScrollAdapterTransform is the default implementation of {@link ScrollAdapterTransform} used
     31  * by ScrollAdapterView. It uses two Animator objects to transform views.
     32  */
     33 public class SimpleScrollAdapterTransform implements ScrollAdapterTransform {
     34 
     35     /** Animator for transform views on the right/down side of mScrollCenter */
     36     private Animator mHighItemTransform;
     37 
     38     /** for transform views on the left/up side of mScrollCenter */
     39     private Animator mLowItemTransform;
     40 
     41     private final DisplayMetrics mDisplayMetrics;
     42 
     43     public SimpleScrollAdapterTransform(Context context) {
     44         mDisplayMetrics = context.getResources().getDisplayMetrics();
     45     }
     46 
     47     @Override
     48     public void transform(View child, int distanceFromCenter, int distanceFromCenter2ndAxis) {
     49         if (mLowItemTransform == null && mHighItemTransform == null) {
     50             return;
     51         }
     52         int absDistance = Math.abs(distanceFromCenter) + Math.abs(distanceFromCenter2ndAxis);
     53         if (distanceFromCenter < 0) {
     54             applyTransformationRecursive(absDistance, mLowItemTransform, child);
     55         } else {
     56             applyTransformationRecursive(absDistance, mHighItemTransform, child);
     57         }
     58     }
     59 
     60     private void applyTransformationRecursive(
     61             int distanceFromCenter, Animator animator, View child) {
     62         if (animator instanceof AnimatorSet) {
     63             ArrayList<Animator> children = ((AnimatorSet) animator).getChildAnimations();
     64             for (int i = children.size() - 1; i >= 0; i--) {
     65                 applyTransformationRecursive(distanceFromCenter, children.get(i), child);
     66             }
     67         } else if (animator instanceof ValueAnimator) {
     68             ValueAnimator valueAnim = ((ValueAnimator) animator);
     69             valueAnim.setTarget(child);
     70             long duration = valueAnim.getDuration();
     71             if (distanceFromCenter < duration) {
     72                 valueAnim.setCurrentPlayTime(distanceFromCenter);
     73             } else {
     74                 valueAnim.setCurrentPlayTime(duration);
     75             }
     76         }
     77     }
     78 
     79     private void initializeTransformationRecursive(Animator animator, long defaultDuration) {
     80         long duration = animator.getDuration();
     81         if (duration == 0) {
     82             duration = defaultDuration;
     83         }
     84         if (animator instanceof AnimatorSet) {
     85             ArrayList<Animator> children = ((AnimatorSet) animator).getChildAnimations();
     86             for (int i = children.size() - 1; i >= 0; i--) {
     87                 initializeTransformationRecursive(children.get(i), duration);
     88             }
     89         } else if (animator instanceof ValueAnimator) {
     90             ValueAnimator valueAnim = ((ValueAnimator) animator);
     91             // DIP to pixel, save back to duration
     92             valueAnim.setDuration((long) TypedValue.applyDimension(
     93                     TypedValue.COMPLEX_UNIT_DIP, duration, mDisplayMetrics));
     94         }
     95     }
     96 
     97     public Animator getHighItemTransform() {
     98         return mHighItemTransform;
     99     }
    100 
    101     public void setHighItemTransform(Animator highItemTransform) {
    102         mHighItemTransform = highItemTransform;
    103         initializeTransformationRecursive(mHighItemTransform, 0);
    104     }
    105 
    106     public Animator getLowItemTransform() {
    107         return mLowItemTransform;
    108     }
    109 
    110     public void setLowItemTransform(Animator lowItemTransform) {
    111         mLowItemTransform = lowItemTransform;
    112         initializeTransformationRecursive(mLowItemTransform, 0);
    113     }
    114 
    115 }
    116