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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 android.transition;
     18 
     19 import android.animation.Animator;
     20 import android.animation.ObjectAnimator;
     21 import android.content.Context;
     22 import android.transition.Transition;
     23 import android.transition.TransitionValues;
     24 import android.util.AttributeSet;
     25 import android.view.View;
     26 import android.view.ViewGroup;
     27 
     28 /**
     29  * This transition captures the scroll properties of targets before and after
     30  * the scene change and animates any changes.
     31  *
     32  * @hide
     33  */
     34 public class ChangeScroll extends Transition {
     35 
     36     private static final String PROPNAME_SCROLL_X = "android:changeScroll:x";
     37     private static final String PROPNAME_SCROLL_Y = "android:changeScroll:y";
     38 
     39     public ChangeScroll() {}
     40 
     41     public ChangeScroll(Context context, AttributeSet attrs) {
     42         super(context, attrs);
     43     }
     44 
     45     @Override
     46     public void captureStartValues(TransitionValues transitionValues) {
     47         captureValues(transitionValues);
     48     }
     49 
     50     @Override
     51     public void captureEndValues(TransitionValues transitionValues) {
     52         captureValues(transitionValues);
     53     }
     54 
     55     private void captureValues(TransitionValues transitionValues) {
     56         transitionValues.values.put(PROPNAME_SCROLL_X, transitionValues.view.getScrollX());
     57         transitionValues.values.put(PROPNAME_SCROLL_Y, transitionValues.view.getScrollY());
     58     }
     59 
     60     @Override
     61     public Animator createAnimator(ViewGroup sceneRoot, TransitionValues startValues,
     62             TransitionValues endValues) {
     63         if (startValues == null || endValues == null) {
     64             return null;
     65         }
     66         final View view = endValues.view;
     67         int startX = (Integer) startValues.values.get(PROPNAME_SCROLL_X);
     68         int endX = (Integer) endValues.values.get(PROPNAME_SCROLL_X);
     69         int startY = (Integer) startValues.values.get(PROPNAME_SCROLL_Y);
     70         int endY = (Integer) endValues.values.get(PROPNAME_SCROLL_Y);
     71         Animator scrollXAnimator = null;
     72         Animator scrollYAnimator = null;
     73         if (startX != endX) {
     74             view.setScrollX(startX);
     75             scrollXAnimator = ObjectAnimator.ofInt(view, "scrollX", startX, endX);
     76         }
     77         if (startY != endY) {
     78             view.setScrollY(startY);
     79             scrollYAnimator = ObjectAnimator.ofInt(view, "scrollY", startY, endY);
     80         }
     81         return TransitionUtils.mergeAnimators(scrollXAnimator, scrollYAnimator);
     82     }
     83 }
     84