1 /*
2  * Copyright (C) 2023 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 package com.android.wallpaper.picker
17 
18 import android.content.Context
19 import android.util.AttributeSet
20 import android.view.MotionEvent
21 import android.view.ViewConfiguration
22 import androidx.core.widget.NestedScrollView
23 import kotlin.math.abs
24 
25 /**
26  * This nested scroll view will detect horizontal touch movements and stop vertical scrolls when a
27  * horizontal touch movement is detected.
28  */
29 class HorizontalTouchMovementAwareNestedScrollView(context: Context, attrs: AttributeSet?) :
30     NestedScrollView(context, attrs) {
31 
32     private var startXPosition = 0f
33     private var startYPosition = 0f
34     private var isHorizontalTouchMovement = false
35 
onInterceptTouchEventnull36     override fun onInterceptTouchEvent(event: MotionEvent): Boolean {
37         when (event.action) {
38             MotionEvent.ACTION_DOWN -> {
39                 startXPosition = event.x
40                 startYPosition = event.y
41                 isHorizontalTouchMovement = false
42             }
43             MotionEvent.ACTION_MOVE -> {
44                 val xMoveDistance = abs(event.x - startXPosition)
45                 val yMoveDistance = abs(event.y - startYPosition)
46                 if (
47                     !isHorizontalTouchMovement &&
48                         xMoveDistance > yMoveDistance &&
49                         xMoveDistance > ViewConfiguration.get(context).scaledTouchSlop
50                 ) {
51                     isHorizontalTouchMovement = true
52                 }
53             }
54             else -> {}
55         }
56         return if (isHorizontalTouchMovement) {
57             // We only want to intercept the touch event when the touch moves more vertically than
58             // horizontally. So we return false.
59             false
60         } else {
61             super.onInterceptTouchEvent(event)
62         }
63     }
64 }
65