1/*
2 * Copyright (C) 2017 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.support.transition;
18
19import android.animation.Animator;
20import android.animation.ObjectAnimator;
21import android.content.Context;
22import android.support.annotation.NonNull;
23import android.support.annotation.Nullable;
24import android.util.AttributeSet;
25import android.view.View;
26import android.view.ViewGroup;
27
28
29/**
30 * This transition captures the scroll properties of targets before and after
31 * the scene change and animates any changes.
32 */
33public class ChangeScroll extends Transition {
34
35    private static final String PROPNAME_SCROLL_X = "android:changeScroll:x";
36    private static final String PROPNAME_SCROLL_Y = "android:changeScroll:y";
37
38    private static final String[] PROPERTIES = {
39            PROPNAME_SCROLL_X,
40            PROPNAME_SCROLL_Y,
41    };
42
43    public ChangeScroll() {}
44
45    public ChangeScroll(Context context, AttributeSet attrs) {
46        super(context, attrs);
47    }
48
49    @Override
50    public void captureStartValues(@NonNull TransitionValues transitionValues) {
51        captureValues(transitionValues);
52    }
53
54    @Override
55    public void captureEndValues(@NonNull TransitionValues transitionValues) {
56        captureValues(transitionValues);
57    }
58
59    @Nullable
60    @Override
61    public String[] getTransitionProperties() {
62        return PROPERTIES;
63    }
64
65    private void captureValues(TransitionValues transitionValues) {
66        transitionValues.values.put(PROPNAME_SCROLL_X, transitionValues.view.getScrollX());
67        transitionValues.values.put(PROPNAME_SCROLL_Y, transitionValues.view.getScrollY());
68    }
69
70    @Nullable
71    @Override
72    public Animator createAnimator(@NonNull ViewGroup sceneRoot,
73            @Nullable TransitionValues startValues, @Nullable TransitionValues endValues) {
74        if (startValues == null || endValues == null) {
75            return null;
76        }
77        final View view = endValues.view;
78        int startX = (Integer) startValues.values.get(PROPNAME_SCROLL_X);
79        int endX = (Integer) endValues.values.get(PROPNAME_SCROLL_X);
80        int startY = (Integer) startValues.values.get(PROPNAME_SCROLL_Y);
81        int endY = (Integer) endValues.values.get(PROPNAME_SCROLL_Y);
82        Animator scrollXAnimator = null;
83        Animator scrollYAnimator = null;
84        if (startX != endX) {
85            view.setScrollX(startX);
86            scrollXAnimator = ObjectAnimator.ofInt(view, "scrollX", startX, endX);
87        }
88        if (startY != endY) {
89            view.setScrollY(startY);
90            scrollYAnimator = ObjectAnimator.ofInt(view, "scrollY", startY, endY);
91        }
92        return TransitionUtils.mergeAnimators(scrollXAnimator, scrollYAnimator);
93    }
94
95}
96