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 androidx.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
26import androidx.annotation.NonNull;
27import androidx.annotation.Nullable;
28
29
30/**
31 * This transition captures the scroll properties of targets before and after
32 * the scene change and animates any changes.
33 */
34public 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    private static final String[] PROPERTIES = {
40            PROPNAME_SCROLL_X,
41            PROPNAME_SCROLL_Y,
42    };
43
44    public ChangeScroll() {}
45
46    public ChangeScroll(Context context, AttributeSet attrs) {
47        super(context, attrs);
48    }
49
50    @Override
51    public void captureStartValues(@NonNull TransitionValues transitionValues) {
52        captureValues(transitionValues);
53    }
54
55    @Override
56    public void captureEndValues(@NonNull TransitionValues transitionValues) {
57        captureValues(transitionValues);
58    }
59
60    @Nullable
61    @Override
62    public String[] getTransitionProperties() {
63        return PROPERTIES;
64    }
65
66    private void captureValues(TransitionValues transitionValues) {
67        transitionValues.values.put(PROPNAME_SCROLL_X, transitionValues.view.getScrollX());
68        transitionValues.values.put(PROPNAME_SCROLL_Y, transitionValues.view.getScrollY());
69    }
70
71    @Nullable
72    @Override
73    public Animator createAnimator(@NonNull ViewGroup sceneRoot,
74            @Nullable TransitionValues startValues, @Nullable TransitionValues endValues) {
75        if (startValues == null || endValues == null) {
76            return null;
77        }
78        final View view = endValues.view;
79        int startX = (Integer) startValues.values.get(PROPNAME_SCROLL_X);
80        int endX = (Integer) endValues.values.get(PROPNAME_SCROLL_X);
81        int startY = (Integer) startValues.values.get(PROPNAME_SCROLL_Y);
82        int endY = (Integer) endValues.values.get(PROPNAME_SCROLL_Y);
83        Animator scrollXAnimator = null;
84        Animator scrollYAnimator = null;
85        if (startX != endX) {
86            view.setScrollX(startX);
87            scrollXAnimator = ObjectAnimator.ofInt(view, "scrollX", startX, endX);
88        }
89        if (startY != endY) {
90            view.setScrollY(startY);
91            scrollYAnimator = ObjectAnimator.ofInt(view, "scrollY", startY, endY);
92        }
93        return TransitionUtils.mergeAnimators(scrollXAnimator, scrollYAnimator);
94    }
95
96}
97