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.util.AttributeSet;
23import android.view.View;
24import android.view.ViewGroup;
25
26/**
27 * This transition captures the scroll properties of targets before and after
28 * the scene change and animates any changes.
29 */
30public class ChangeScroll extends Transition {
31
32    private static final String PROPNAME_SCROLL_X = "android:changeScroll:x";
33    private static final String PROPNAME_SCROLL_Y = "android:changeScroll:y";
34
35    private static final String[] PROPERTIES = {
36            PROPNAME_SCROLL_X,
37            PROPNAME_SCROLL_Y,
38    };
39
40    public ChangeScroll() {}
41
42    public ChangeScroll(Context context, AttributeSet attrs) {
43        super(context, attrs);
44    }
45
46    @Override
47    public void captureStartValues(TransitionValues transitionValues) {
48        captureValues(transitionValues);
49    }
50
51    @Override
52    public void captureEndValues(TransitionValues transitionValues) {
53        captureValues(transitionValues);
54    }
55
56    @Override
57    public String[] getTransitionProperties() {
58        return PROPERTIES;
59    }
60
61    private void captureValues(TransitionValues transitionValues) {
62        transitionValues.values.put(PROPNAME_SCROLL_X, transitionValues.view.getScrollX());
63        transitionValues.values.put(PROPNAME_SCROLL_Y, transitionValues.view.getScrollY());
64    }
65
66    @Override
67    public Animator createAnimator(ViewGroup sceneRoot, TransitionValues startValues,
68            TransitionValues endValues) {
69        if (startValues == null || endValues == null) {
70            return null;
71        }
72        final View view = endValues.view;
73        int startX = (Integer) startValues.values.get(PROPNAME_SCROLL_X);
74        int endX = (Integer) endValues.values.get(PROPNAME_SCROLL_X);
75        int startY = (Integer) startValues.values.get(PROPNAME_SCROLL_Y);
76        int endY = (Integer) endValues.values.get(PROPNAME_SCROLL_Y);
77        Animator scrollXAnimator = null;
78        Animator scrollYAnimator = null;
79        if (startX != endX) {
80            view.setScrollX(startX);
81            scrollXAnimator = ObjectAnimator.ofInt(view, "scrollX", startX, endX);
82        }
83        if (startY != endY) {
84            view.setScrollY(startY);
85            scrollYAnimator = ObjectAnimator.ofInt(view, "scrollY", startY, endY);
86        }
87        return TransitionUtils.mergeAnimators(scrollXAnimator, scrollYAnimator);
88    }
89}
90