1 /* 2 * Copyright (C) 2025 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.notifications.ui.composable 18 19 import androidx.compose.animation.core.AnimationState 20 import androidx.compose.animation.core.DecayAnimationSpec 21 import androidx.compose.animation.core.animateDecay 22 import androidx.compose.foundation.gestures.FlingBehavior 23 import androidx.compose.foundation.gestures.ScrollScope 24 import androidx.compose.ui.MotionDurationScale 25 import com.android.systemui.scene.session.ui.composable.rememberSession 26 import kotlinx.coroutines.CancellationException 27 import kotlinx.coroutines.withContext 28 import kotlin.math.abs 29 30 /** 31 * Fork of [androidx.compose.foundation.gestures.DefaultFlingBehavior] to allow us to use it with 32 * [rememberSession]. 33 */ 34 internal class NotificationScrimFlingBehavior( 35 private var flingDecay: DecayAnimationSpec<Float>, 36 private val motionDurationScale: MotionDurationScale = NotificationScrimMotionDurationScale 37 ) : FlingBehavior { performFlingnull38 override suspend fun ScrollScope.performFling(initialVelocity: Float): Float { 39 // come up with the better threshold, but we need it since spline curve gives us NaNs 40 return withContext(motionDurationScale) { 41 if (abs(initialVelocity) > 1f) { 42 var velocityLeft = initialVelocity 43 var lastValue = 0f 44 val animationState = 45 AnimationState( 46 initialValue = 0f, 47 initialVelocity = initialVelocity, 48 ) 49 try { 50 animationState.animateDecay(flingDecay) { 51 val delta = value - lastValue 52 val consumed = scrollBy(delta) 53 lastValue = value 54 velocityLeft = this.velocity 55 // avoid rounding errors and stop if anything is unconsumed 56 if (abs(delta - consumed) > 0.5f) this.cancelAnimation() 57 } 58 } catch (exception: CancellationException) { 59 velocityLeft = animationState.velocity 60 } 61 velocityLeft 62 } else { 63 initialVelocity 64 } 65 } 66 } 67 } 68 69 internal val NotificationScrimMotionDurationScale = 70 object : MotionDurationScale { 71 override val scaleFactor: Float 72 get() = 1f 73 }