ChangeScroll.java revision ae61b85cb595ad157000279e77475900a3f44e05 
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
17package android.transition;
18
19import android.animation.Animator;
20import android.animation.ObjectAnimator;
21import android.content.Context;
22import android.transition.Transition;
23import android.transition.TransitionValues;
24import android.util.AttributeSet;
25import android.view.View;
26import 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 */
32public class ChangeScroll extends Transition {
33
34    private static final String PROPNAME_SCROLL_X = "android:changeScroll:x";
35    private static final String PROPNAME_SCROLL_Y = "android:changeScroll:y";
36
37    private static final String[] PROPERTIES = {
38            PROPNAME_SCROLL_X,
39            PROPNAME_SCROLL_Y,
40    };
41
42    public ChangeScroll() {}
43
44    public ChangeScroll(Context context, AttributeSet attrs) {
45        super(context, attrs);
46    }
47
48    @Override
49    public void captureStartValues(TransitionValues transitionValues) {
50        captureValues(transitionValues);
51    }
52
53    @Override
54    public void captureEndValues(TransitionValues transitionValues) {
55        captureValues(transitionValues);
56    }
57
58    @Override
59    public String[] getTransitionProperties() {
60        return PROPERTIES;
61    }
62
63    private void captureValues(TransitionValues transitionValues) {
64        transitionValues.values.put(PROPNAME_SCROLL_X, transitionValues.view.getScrollX());
65        transitionValues.values.put(PROPNAME_SCROLL_Y, transitionValues.view.getScrollY());
66    }
67
68    @Override
69    public Animator createAnimator(ViewGroup sceneRoot, TransitionValues startValues,
70            TransitionValues endValues) {
71        if (startValues == null || endValues == null) {
72            return null;
73        }
74        final View view = endValues.view;
75        int startX = (Integer) startValues.values.get(PROPNAME_SCROLL_X);
76        int endX = (Integer) endValues.values.get(PROPNAME_SCROLL_X);
77        int startY = (Integer) startValues.values.get(PROPNAME_SCROLL_Y);
78        int endY = (Integer) endValues.values.get(PROPNAME_SCROLL_Y);
79        Animator scrollXAnimator = null;
80        Animator scrollYAnimator = null;
81        if (startX != endX) {
82            view.setScrollX(startX);
83            scrollXAnimator = ObjectAnimator.ofInt(view, "scrollX", startX, endX);
84        }
85        if (startY != endY) {
86            view.setScrollY(startY);
87            scrollYAnimator = ObjectAnimator.ofInt(view, "scrollY", startY, endY);
88        }
89        return TransitionUtils.mergeAnimators(scrollXAnimator, scrollYAnimator);
90    }
91}
92