Improve predictive back on iOS

joreilly · Dec 14, 2024 · f109595 · f109595
1 parent 4b6857e
commit f109595
Show file tree

Hide file tree

Showing 2 changed files with 22 additions and 5 deletions.
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
@@ -20,7 +20,7 @@ compose-material3 = "1.3.1"
 compose-ui-tooling = "1.4.0"
 composeWindowSize = "0.5.0"
 credentials = "1.5.0-beta01"
-decompose = "3.2.2"
+decompose = "3.3.0-alpha02"
 essenty = "2.4.0"
 googleid = "1.1.1"
 horologist = "0.7.7-alpha"

diff --git a/shared/src/iosMain/kotlin/dev/johnoreilly/confetti/ui/PredictiveBackAnimation.ios.kt b/shared/src/iosMain/kotlin/dev/johnoreilly/confetti/ui/PredictiveBackAnimation.ios.kt
@@ -1,11 +1,19 @@
 package dev.johnoreilly.confetti.ui
 
+import androidx.compose.animation.core.FastOutSlowInEasing
+import androidx.compose.animation.core.FiniteAnimationSpec
+import androidx.compose.animation.core.LinearEasing
+import androidx.compose.animation.core.tween
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.drawWithContent
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.layout.layout
 import com.arkivanov.decompose.ExperimentalDecomposeApi
-import com.arkivanov.decompose.extensions.compose.experimental.stack.animation.*
+import com.arkivanov.decompose.extensions.compose.experimental.stack.animation.PredictiveBackParams
+import com.arkivanov.decompose.extensions.compose.experimental.stack.animation.StackAnimation
+import com.arkivanov.decompose.extensions.compose.experimental.stack.animation.StackAnimator
+import com.arkivanov.decompose.extensions.compose.experimental.stack.animation.stackAnimation
+import com.arkivanov.decompose.extensions.compose.experimental.stack.animation.stackAnimator
 import com.arkivanov.decompose.extensions.compose.stack.animation.isFront
 import com.arkivanov.essenty.backhandler.BackHandler
 
@@ -15,18 +23,27 @@ internal actual fun <C : Any, T : Any> predictiveBackAnimation(
     onBack: () -> Unit,
 ): StackAnimation<C, T> =
     stackAnimation(
-        animator = iosLikeSlide(),
         predictiveBackParams = {
             PredictiveBackParams(
                 backHandler = backHandler,
                 onBack = onBack,
             )
         },
+        selector = { _, _, _, isPredictiveBack ->
+            iosLikeSlide(iosAnimationSpec(isPredictiveBack = isPredictiveBack))
+        },
     )
 
+private fun iosAnimationSpec(isPredictiveBack: Boolean): FiniteAnimationSpec<Float> =
+    if (isPredictiveBack) {
+        tween(easing = LinearEasing, durationMillis = 150)
+    } else {
+        tween(easing = FastOutSlowInEasing)
+    }
+
 @ExperimentalDecomposeApi
-private fun iosLikeSlide(): StackAnimator =
-    stackAnimator { factor, direction ->
+private fun iosLikeSlide(animationSpec: FiniteAnimationSpec<Float>): StackAnimator =
+    stackAnimator(animationSpec = animationSpec) { factor, direction ->
         Modifier
             .then(if (direction.isFront) Modifier else Modifier.fade(factor + 1F))
             .offsetXFactor(factor = if (direction.isFront) factor else factor * 0.5F)