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
17 package com.android.systemui.animation.back
18
19 import android.annotation.IntRange
20 import android.util.DisplayMetrics
21 import android.view.View
22 import android.window.BackEvent
23 import android.window.OnBackAnimationCallback
24 import android.window.OnBackInvokedDispatcher
25 import android.window.OnBackInvokedDispatcher.Priority
26 import com.android.app.animation.Interpolators
27
28 /**
29 * Generates an [OnBackAnimationCallback] given a [backAnimationSpec]. [onBackProgressed] will be
30 * called on each update passing the current [BackTransformation].
31 *
32 * Optionally, you can specify [onBackStarted], [onBackInvoked], and [onBackCancelled] callbacks.
33 *
34 * @sample com.android.systemui.util.registerAnimationOnBackInvoked
35 */
onBackAnimationCallbackFromnull36 fun onBackAnimationCallbackFrom(
37 backAnimationSpec: BackAnimationSpec,
38 displayMetrics: DisplayMetrics, // TODO(b/265060720): We could remove this
39 onBackProgressed: (BackTransformation) -> Unit,
40 onBackStarted: (BackEvent) -> Unit = {},
<lambda>null41 onBackInvoked: () -> Unit = {},
<lambda>null42 onBackCancelled: () -> Unit = {},
43 ): OnBackAnimationCallback {
44 return object : FlingOnBackAnimationCallback(progressInterpolator = Interpolators.LINEAR) {
45 private var initialY = 0f
46 private val lastTransformation = BackTransformation()
47
onBackStartedCompatnull48 override fun onBackStartedCompat(backEvent: BackEvent) {
49 initialY = backEvent.touchY
50 onBackStarted(backEvent)
51 }
52
onBackProgressedCompatnull53 override fun onBackProgressedCompat(backEvent: BackEvent) {
54 val progressY = (backEvent.touchY - initialY) / displayMetrics.heightPixels
55
56 backAnimationSpec.getBackTransformation(
57 backEvent = backEvent,
58 progressY = progressY,
59 result = lastTransformation,
60 )
61
62 onBackProgressed(lastTransformation)
63 }
64
onBackInvokedCompatnull65 override fun onBackInvokedCompat() {
66 onBackInvoked()
67 }
68
onBackCancelledCompatnull69 override fun onBackCancelledCompat() {
70 onBackCancelled()
71 }
72 }
73 }
74
75 /**
76 * Register [OnBackAnimationCallback] when View is attached and unregister it when View is detached
77 *
78 * @sample com.android.systemui.util.registerAnimationOnBackInvoked
79 */
registerOnBackInvokedCallbackOnViewAttachednull80 fun View.registerOnBackInvokedCallbackOnViewAttached(
81 onBackInvokedDispatcher: OnBackInvokedDispatcher,
82 onBackAnimationCallback: OnBackAnimationCallback,
83 @Priority @IntRange(from = 0) priority: Int = OnBackInvokedDispatcher.PRIORITY_DEFAULT,
84 ) {
85 addOnAttachStateChangeListener(
86 object : View.OnAttachStateChangeListener {
87 override fun onViewAttachedToWindow(v: View) {
88 onBackInvokedDispatcher.registerOnBackInvokedCallback(
89 priority,
90 onBackAnimationCallback,
91 )
92 }
93
94 override fun onViewDetachedFromWindow(v: View) {
95 removeOnAttachStateChangeListener(this)
96 onBackInvokedDispatcher.unregisterOnBackInvokedCallback(onBackAnimationCallback)
97 }
98 }
99 )
100
101 if (isAttachedToWindow) {
102 onBackInvokedDispatcher.registerOnBackInvokedCallback(priority, onBackAnimationCallback)
103 }
104 }
105