add back in predictive back animations (#118)

* add back in predictive back animations

* spotless apply

Author: ashnohe

app/src/main/java/com/google/android/samples/socialite/ui/Main.kt

@@ -20,14 +20,17 @@ import android.app.Activity
 import android.content.Intent
 import android.content.pm.ActivityInfo
 import android.os.Bundle
+import androidx.compose.animation.EnterTransition
 import androidx.compose.animation.core.FastOutLinearInEasing
 import androidx.compose.animation.core.FastOutSlowInEasing
 import androidx.compose.animation.core.tween
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
+import androidx.compose.animation.scaleOut
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.TransformOrigin
 import androidx.compose.ui.platform.LocalContext
 import androidx.navigation.NavController
 import androidx.navigation.NavDestination
@@ -88,6 +91,15 @@ fun MainNavigation(
         NavHost(
             navController = navController,
             startDestination = Route.ChatsList,
+            popExitTransition = {
+                scaleOut(
+                    targetScale = 0.9f,
+                    transformOrigin = TransformOrigin(pivotFractionX = 0.5f, pivotFractionY = 0.5f),
+                )
+            },
+            popEnterTransition = {
+                EnterTransition.None
+            },
         ) {
             composable<Route.ChatsList> {
                 ChatList(