1 /*
2  * Copyright (C) 2018 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 com.android.settings.widget;
18 
19 import android.content.Context;
20 import android.graphics.Color;
21 import android.util.AttributeSet;
22 import android.view.View;
23 
24 import androidx.annotation.VisibleForTesting;
25 import androidx.coordinatorlayout.widget.CoordinatorLayout;
26 
27 import com.google.android.material.appbar.AppBarLayout;
28 
29 /**
30  * This scrolling view behavior will set the background of the {@link AppBarLayout} as
31  * transparent and without the elevation. Also make header overlapped the scrolling child view.
32  */
33 public class FloatingAppBarScrollingViewBehavior extends AppBarLayout.ScrollingViewBehavior {
34     private boolean initialized;
35 
FloatingAppBarScrollingViewBehavior(Context context, AttributeSet attrs)36     public FloatingAppBarScrollingViewBehavior(Context context, AttributeSet attrs) {
37         super(context, attrs);
38     }
39 
40     @Override
onDependentViewChanged(CoordinatorLayout parent, View child, View dependency)41     public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {
42         boolean changed = super.onDependentViewChanged(parent, child, dependency);
43         if (!initialized && dependency instanceof AppBarLayout) {
44             initialized = true;
45             AppBarLayout appBarLayout = (AppBarLayout) dependency;
46             setAppBarLayoutTransparent(appBarLayout);
47         }
48         return changed;
49     }
50 
51     @VisibleForTesting
setAppBarLayoutTransparent(AppBarLayout appBarLayout)52     void setAppBarLayoutTransparent(AppBarLayout appBarLayout) {
53         appBarLayout.setBackgroundColor(Color.TRANSPARENT);
54         appBarLayout.setTargetElevation(0);
55     }
56 
57     @Override
shouldHeaderOverlapScrollingChild()58     protected boolean shouldHeaderOverlapScrollingChild() {
59         return true;
60     }
61 }
62