Improves performance of video loading and playback.

app/src/main/java/com/vitorpamplona/amethyst/VideoCache.kt

@@ -18,7 +18,7 @@ object VideoCache {
 
     lateinit var cacheDataSourceFactory: CacheDataSource.Factory
 
-    fun get(context: Context): CacheDataSource.Factory {
+    fun init(context: Context) {
         if (!this::simpleCache.isInitialized) {
             exoDatabaseProvider = StandaloneDatabaseProvider(context)
 
@@ -35,7 +35,9 @@ object VideoCache {
                 )
                 .setFlags(CacheDataSource.FLAG_IGNORE_CACHE_ON_ERROR)
         }
+    }
 
+    fun get(): CacheDataSource.Factory {
         return cacheDataSourceFactory
     }
 }

app/src/main/java/com/vitorpamplona/amethyst/ui/MainActivity.kt

@@ -19,6 +19,7 @@ import coil.decode.ImageDecoderDecoder
 import coil.decode.SvgDecoder
 import com.vitorpamplona.amethyst.LocalPreferences
 import com.vitorpamplona.amethyst.ServiceManager
+import com.vitorpamplona.amethyst.VideoCache
 import com.vitorpamplona.amethyst.service.nip19.Nip19
 import com.vitorpamplona.amethyst.service.relays.Client
 import com.vitorpamplona.amethyst.ui.navigation.Route
@@ -54,6 +55,9 @@ class MainActivity : FragmentActivity() {
             null
         }
 
+        // Initializes video cache.
+        VideoCache.init(this.applicationContext)
+
         Coil.setImageLoader {
             ImageLoader.Builder(this).components {
                 if (SDK_INT >= 28) {

app/src/main/java/com/vitorpamplona/amethyst/ui/components/VideoView.kt

@@ -6,9 +6,13 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberUpdatedState
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.LocalLifecycleOwner
 import androidx.compose.ui.viewinterop.AndroidView
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleEventObserver
 import com.google.android.exoplayer2.C
 import com.google.android.exoplayer2.ExoPlayer
 import com.google.android.exoplayer2.MediaItem
@@ -21,19 +25,23 @@ import com.vitorpamplona.amethyst.VideoCache
 @Composable
 fun VideoView(videoUri: String, onDialog: ((Boolean) -> Unit)? = null) {
     val context = LocalContext.current
+    val lifecycleOwner = rememberUpdatedState(LocalLifecycleOwner.current)
 
-    val exoPlayer = remember {
+    val exoPlayer = remember(videoUri) {
         ExoPlayer.Builder(context).build().apply {
             repeatMode = Player.REPEAT_MODE_ALL
             videoScalingMode = C.VIDEO_SCALING_MODE_SCALE_TO_FIT_WITH_CROPPING
             setMediaSource(
-                ProgressiveMediaSource.Factory(VideoCache.get(context.applicationContext)).createMediaSource(MediaItem.fromUri(videoUri))
+                ProgressiveMediaSource.Factory(VideoCache.get()).createMediaSource(MediaItem.fromUri(videoUri))
             )
             prepare()
         }
     }
 
-    val playerView = remember {
+    DisposableEffect(
+        AndroidView(
+            modifier = Modifier.fillMaxWidth(),
+            factory = {
                 StyledPlayerView(context).apply {
                     player = exoPlayer
                     layoutParams = FrameLayout.LayoutParams(
@@ -43,22 +51,28 @@ fun VideoView(videoUri: String, onDialog: ((Boolean) -> Unit)? = null) {
                     resizeMode = AspectRatioFrameLayout.RESIZE_MODE_FIXED_WIDTH
                     onDialog?.let { innerOnDialog ->
                         setFullscreenButtonClickListener {
+                            exoPlayer.pause()
                             innerOnDialog(it)
                         }
                     }
                 }
             }
+        )
+    ) {
+        val observer = LifecycleEventObserver { _, event ->
+            when (event) {
+                Lifecycle.Event.ON_PAUSE -> {
+                    exoPlayer.pause()
+                }
+                else -> {}
+            }
+        }
+        val lifecycle = lifecycleOwner.value.lifecycle
+        lifecycle.addObserver(observer)
 
-    DisposableEffect(exoPlayer) {
         onDispose {
             exoPlayer.release()
+            lifecycle.removeObserver(observer)
         }
     }
-
-    AndroidView(
-        modifier = Modifier.fillMaxWidth(),
-        factory = {
-            playerView
-        }
-    )
 }