1 /*
2  * Copyright (C) 2016 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.launcher3.accessibility
17 
18 import android.view.View
19 import android.view.ViewGroup
20 import com.android.launcher3.CellLayout
21 import com.android.launcher3.DropTarget.DragObject
22 import com.android.launcher3.dragndrop.DragController
23 import com.android.launcher3.dragndrop.DragOptions
24 import com.android.launcher3.views.ActivityContext
25 import java.util.function.Function
26 
27 /**
28  * Utility listener to enable/disable accessibility drag flags for a ViewGroup containing
29  * CellLayouts
30  */
31 open class AccessibleDragListenerAdapter
32 /**
33  * @param parent the viewgroup containing all the children
34  * @param delegateFactory function to create no delegates
35  */
36 (
37     private val mViewGroup: ViewGroup,
38     private val mDelegateFactory: Function<CellLayout, DragAndDropAccessibilityDelegate>
39 ) : DragController.DragListener, ViewGroup.OnHierarchyChangeListener {
onDragStartnull40     override fun onDragStart(dragObject: DragObject, options: DragOptions) {
41         mViewGroup.setOnHierarchyChangeListener(this)
42         enableAccessibleDrag(true, dragObject)
43     }
44 
onDragEndnull45     override fun onDragEnd() {
46         mViewGroup.setOnHierarchyChangeListener(null)
47         enableAccessibleDrag(false, null)
48         val activityContext = ActivityContext.lookupContext(mViewGroup.context) as ActivityContext
49         activityContext.getDragController<DragController<*>>()?.removeDragListener(this)
50     }
51 
onChildViewAddednull52     override fun onChildViewAdded(parent: View, child: View) {
53         if (parent === mViewGroup) {
54             setEnableForLayout(child as CellLayout, true)
55         }
56     }
57 
onChildViewRemovednull58     override fun onChildViewRemoved(parent: View, child: View) {
59         if (parent === mViewGroup) {
60             setEnableForLayout(child as CellLayout, false)
61         }
62     }
63 
enableAccessibleDragnull64     protected open fun enableAccessibleDrag(enable: Boolean, dragObject: DragObject?) {
65         for (i in 0 until mViewGroup.childCount) {
66             setEnableForLayout(mViewGroup.getChildAt(i) as CellLayout, enable)
67         }
68     }
69 
setEnableForLayoutnull70     protected fun setEnableForLayout(layout: CellLayout, enable: Boolean) {
71         layout.setDragAndDropAccessibilityDelegate(
72             if (enable) mDelegateFactory.apply(layout) else null
73         )
74     }
75 }
76