update screen transition

docs/transitions-api.md

@@ -80,20 +80,96 @@ setContent {
 
 If you want to define a Enter and Exit transition for a specific Screen, you have a lot of options to do
 starting from 1.1.0-beta01 Voyager have a new experimental API for this purpose.
+To animate the content, we use transitions of the target screen in the case of push navigation, otherwise we use transitions of the initial screen 
 
 ```kotlin
-class ExampleScaleScreen : Screen, ScreenTransition {
+class ExampleSlideScreen : Screen, ScreenTransition {
     override val key: ScreenKey
         get() = uniqueScreenKey
 
     @Composable
     override fun Content() {
         ...
     }
-
-    override fun enter(): EnterTransition? = scaleIn()
 
-    override fun exit(): ExitTransition? = scaleOut()
+    override fun enter(lastEvent: StackEvent): EnterTransition {
+        return slideIn { size ->
+            val x = if (lastEvent == StackEvent.Pop) -size.width else size.width
+            IntOffset(x = x, y = 0)
+        }
+    }
+
+    override fun exit(lastEvent: StackEvent): ExitTransition {
+        return slideOut { size ->
+            val x = if (lastEvent == StackEvent.Pop) size.width else -size.width
+            IntOffset(x = x, y = 0)
+        }
+    }
+}
+```
+
+It's convenient to use Kotlin delegates for per-Screen transitions. For example, you can create a `SlideTransition` and `FadeTransition` classes:
+
+```kotlin
+class FadeTransition : ScreenTransition {
+
+    override fun enter(lastEvent: StackEvent): EnterTransition {
+        return fadeIn(tween(500, delayMillis = 500))
+    }
+
+    override fun exit(lastEvent: StackEvent): ExitTransition {
+        return fadeOut(tween(500))
+    }
+}
+
+class SlideTransition : ScreenTransition {
+
+    override fun enter(lastEvent: StackEvent): EnterTransition {
+        return slideIn { size ->
+            val x = if (lastEvent == StackEvent.Pop) -size.width else size.width
+            IntOffset(x = x, y = 0)
+        }
+    }
+
+    override fun exit(lastEvent: StackEvent): ExitTransition {
+        return slideOut { size ->
+            val x = if (lastEvent == StackEvent.Pop) size.width else -size.width
+            IntOffset(x = x, y = 0)
+        }
+    }
+}
+```
+
+Then you can use them as delegates in your Screens:
+
+```kotlin
+class SlideScreen : Screen, ScreenTransition by SlideTransition() {
+
+    @Composable
+    override fun Content() {
+        ...
+    }
+}
+
+class FadeScreen : Screen, ScreenTransition by FadeTransition() {
+
+    @Composable
+    override fun Content() {
+        ...
+    }
+}
+```
+
+Also you can use can pass your custom `ScreenTransition` instance in `ScreenTransition` function, it will be used for default animation.
+
+```kotlin
+setContent {
+    Navigator(FadeScreen) { navigator ->
+        ScreenTransition(
+            navigator = navigator,
+            defaultTransition = SlideTransition()
+        )
+    }
 }
 ```
 

samples/android/src/main/AndroidManifest.xml

@@ -24,6 +24,7 @@
         <activity android:name=".nestedNavigation.NestedNavigationActivity"/>
         <activity android:name=".parcelableScreen.ParcelableActivity"/>
         <activity android:name=".screenModel.ScreenModelActivity"/>
+        <activity android:name=".screenTransition.ScreenTransitionActivity"/>
         <activity android:name=".androidViewModel.AndroidViewModelActivity"/>
         <activity android:name=".bottomSheetNavigation.BottomSheetNavigationActivity"/>
         <activity android:name=".rxJavaIntegration.RxJavaIntegrationActivity"/>

samples/android/src/main/java/cafe/adriel/voyager/sample/SampleActivity.kt

@@ -30,6 +30,7 @@ import cafe.adriel.voyager.sample.nestedNavigation.NestedNavigationActivity
 import cafe.adriel.voyager.sample.parcelableScreen.ParcelableActivity
 import cafe.adriel.voyager.sample.rxJavaIntegration.RxJavaIntegrationActivity
 import cafe.adriel.voyager.sample.screenModel.ScreenModelActivity
+import cafe.adriel.voyager.sample.screenTransition.ScreenTransitionActivity
 import cafe.adriel.voyager.sample.stateStack.StateStackActivity
 import cafe.adriel.voyager.sample.tabNavigation.TabNavigationActivity
 
@@ -66,6 +67,7 @@ class SampleActivity : ComponentActivity() {
                 StartSampleButton<LiveDataIntegrationActivity>("LiveData Integration")
                 StartSampleButton<HiltMainActivity>("Hilt Integration")
                 StartSampleButton<LegacyActivity>("Legacy Integration")
+                StartSampleButton<ScreenTransitionActivity>("Screen Transition")
             }
         }
     }

samples/android/src/main/java/cafe/adriel/voyager/sample/screenTransition/SampleScreens.kt

@@ -0,0 +1,68 @@
+package cafe.adriel.voyager.sample.screenTransition
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import cafe.adriel.voyager.core.screen.Screen
+import cafe.adriel.voyager.core.screen.ScreenKey
+import cafe.adriel.voyager.transitions.ScreenTransition
+
+private val colors = listOf(
+    Color.Red,
+    Color.Yellow,
+    Color.Green,
+    Color.Blue,
+    Color.Black
+)
+
+abstract class BaseSampleScreen(
+    private val transitionType: String
+) : Screen {
+
+    abstract val index: Int
+
+    override val key: ScreenKey get() = "SampleScreen$index"
+
+    @Composable
+    override fun Content() {
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .background(colors[index % colors.size].copy(alpha = 0.3f))
+                .padding(40.dp),
+            verticalArrangement = Arrangement.Center,
+            horizontalAlignment = Alignment.CenterHorizontally
+        ) {
+            Text(
+                text = "Screen $index",
+                fontSize = 24.sp,
+                fontWeight = FontWeight.Bold
+            )
+            Spacer(modifier = Modifier.height(8.dp))
+            Text(
+                text = transitionType,
+                fontSize = 18.sp
+            )
+        }
+    }
+}
+
+data class NoCustomAnimationSampleScreen(
+    override val index: Int
+) : BaseSampleScreen("Default transition")
+
+data class FadeAnimationSampleScreen(
+    override val index: Int
+) : BaseSampleScreen("Fade transition"), ScreenTransition by FadeTransition()

samples/android/src/main/java/cafe/adriel/voyager/sample/screenTransition/SampleTransitions.kt

@@ -0,0 +1,40 @@
+package cafe.adriel.voyager.sample.screenTransition
+
+import androidx.compose.animation.EnterTransition
+import androidx.compose.animation.ExitTransition
+import androidx.compose.animation.core.tween
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.slideIn
+import androidx.compose.animation.slideOut
+import androidx.compose.ui.unit.IntOffset
+import cafe.adriel.voyager.core.stack.StackEvent
+import cafe.adriel.voyager.transitions.ScreenTransition
+
+class FadeTransition : ScreenTransition {
+
+    override fun enter(lastEvent: StackEvent): EnterTransition {
+        return fadeIn(tween(500, delayMillis = 500))
+    }
+
+    override fun exit(lastEvent: StackEvent): ExitTransition {
+        return fadeOut(tween(500))
+    }
+}
+
+class SlideTransition : ScreenTransition {
+
+    override fun enter(lastEvent: StackEvent): EnterTransition {
+        return slideIn { size ->
+            val x = if (lastEvent == StackEvent.Pop) -size.width else size.width
+            IntOffset(x = x, y = 0)
+        }
+    }
+
+    override fun exit(lastEvent: StackEvent): ExitTransition {
+        return slideOut { size ->
+            val x = if (lastEvent == StackEvent.Pop) size.width else -size.width
+            IntOffset(x = x, y = 0)
+        }
+    }
+}

samples/android/src/main/java/cafe/adriel/voyager/sample/screenTransition/ScreenTransitionActivity.kt

@@ -0,0 +1,73 @@
+package cafe.adriel.voyager.sample.screenTransition
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.Button
+import androidx.compose.material.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import cafe.adriel.voyager.navigator.Navigator
+import cafe.adriel.voyager.transitions.ScreenTransition
+
+class ScreenTransitionActivity : ComponentActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        setContent {
+            Content()
+        }
+    }
+
+    @Composable
+    fun Content() {
+        Navigator(
+            screen = NoCustomAnimationSampleScreen(0)
+        ) { navigator ->
+            Box(modifier = Modifier.fillMaxSize()) {
+                ScreenTransition(
+                    navigator = navigator,
+                    defaultTransition = SlideTransition()
+                )
+
+                Row(
+                    modifier = Modifier
+                        .align(Alignment.BottomCenter)
+                        .fillMaxWidth()
+                        .padding(40.dp),
+                    horizontalArrangement = Arrangement.spacedBy(20.dp)
+                ) {
+                    Button(
+                        onClick = { navigator.push(FadeAnimationSampleScreen(navigator.items.size)) },
+                        modifier = Modifier.weight(1f)
+                    ) {
+                        Text(text = "Fade")
+                    }
+
+                    Button(
+                        onClick = { navigator.push(NoCustomAnimationSampleScreen(navigator.items.size)) },
+                        modifier = Modifier.weight(1f)
+                    ) {
+                        Text(text = "Default")
+                    }
+
+                    Button(
+                        onClick = { navigator.pop() },
+                        modifier = Modifier.weight(1f)
+                    ) {
+                        Text(text = "Pop")
+                    }
+                }
+            }
+        }
+    }
+}

voyager-transitions/api/android/voyager-transitions.api

@@ -23,9 +23,11 @@ public final class cafe/adriel/voyager/transitions/ComposableSingletons$ScreenTr
 	public static final field INSTANCE Lcafe/adriel/voyager/transitions/ComposableSingletons$ScreenTransitionKt;
 	public static field lambda-1 Lkotlin/jvm/functions/Function4;
 	public static field lambda-2 Lkotlin/jvm/functions/Function4;
+	public static field lambda-3 Lkotlin/jvm/functions/Function4;
 	public fun <init> ()V
 	public final fun getLambda-1$voyager_transitions_release ()Lkotlin/jvm/functions/Function4;
 	public final fun getLambda-2$voyager_transitions_release ()Lkotlin/jvm/functions/Function4;
+	public final fun getLambda-3$voyager_transitions_release ()Lkotlin/jvm/functions/Function4;
 }
 
 public final class cafe/adriel/voyager/transitions/ComposableSingletons$SlideTransitionKt {
@@ -48,8 +50,8 @@ public final class cafe/adriel/voyager/transitions/ScaleTransitionKt {
 }
 
 public final class cafe/adriel/voyager/transitions/ScreenTransition$DefaultImpls {
-	public static fun enter (Lcafe/adriel/voyager/transitions/ScreenTransition;)Landroidx/compose/animation/EnterTransition;
-	public static fun exit (Lcafe/adriel/voyager/transitions/ScreenTransition;)Landroidx/compose/animation/ExitTransition;
+	public static fun enter (Lcafe/adriel/voyager/transitions/ScreenTransition;Lcafe/adriel/voyager/core/stack/StackEvent;)Landroidx/compose/animation/EnterTransition;
+	public static fun exit (Lcafe/adriel/voyager/transitions/ScreenTransition;Lcafe/adriel/voyager/core/stack/StackEvent;)Landroidx/compose/animation/ExitTransition;
 }
 
 public final class cafe/adriel/voyager/transitions/ScreenTransitionKt {

voyager-transitions/api/desktop/voyager-transitions.api

@@ -23,9 +23,11 @@ public final class cafe/adriel/voyager/transitions/ComposableSingletons$ScreenTr
 	public static final field INSTANCE Lcafe/adriel/voyager/transitions/ComposableSingletons$ScreenTransitionKt;
 	public static field lambda-1 Lkotlin/jvm/functions/Function4;
 	public static field lambda-2 Lkotlin/jvm/functions/Function4;
+	public static field lambda-3 Lkotlin/jvm/functions/Function4;
 	public fun <init> ()V
 	public final fun getLambda-1$voyager_transitions ()Lkotlin/jvm/functions/Function4;
 	public final fun getLambda-2$voyager_transitions ()Lkotlin/jvm/functions/Function4;
+	public final fun getLambda-3$voyager_transitions ()Lkotlin/jvm/functions/Function4;
 }
 
 public final class cafe/adriel/voyager/transitions/ComposableSingletons$SlideTransitionKt {
@@ -48,8 +50,8 @@ public final class cafe/adriel/voyager/transitions/ScaleTransitionKt {
 }
 
 public final class cafe/adriel/voyager/transitions/ScreenTransition$DefaultImpls {
-	public static fun enter (Lcafe/adriel/voyager/transitions/ScreenTransition;)Landroidx/compose/animation/EnterTransition;
-	public static fun exit (Lcafe/adriel/voyager/transitions/ScreenTransition;)Landroidx/compose/animation/ExitTransition;
+	public static fun enter (Lcafe/adriel/voyager/transitions/ScreenTransition;Lcafe/adriel/voyager/core/stack/StackEvent;)Landroidx/compose/animation/EnterTransition;
+	public static fun exit (Lcafe/adriel/voyager/transitions/ScreenTransition;Lcafe/adriel/voyager/core/stack/StackEvent;)Landroidx/compose/animation/ExitTransition;
 }
 
 public final class cafe/adriel/voyager/transitions/ScreenTransitionKt {