Add multi-language subtitle support to ExoPlayer

README.md

@@ -12,6 +12,7 @@ Android NDK and the libtorrent-rasterbar C++ library.
 - Collapsible per-file progress list — file name, size, and individual download progress bar
 - ETA, total size, and upload ratio on each card (e.g. `151.7 MB / 263.6 MB  •  ETA 27s  •  ratio 0.42`)
 - Sequential download + in-app ExoPlayer — tap Play (≥ 5 % downloaded) to watch before the file is complete; position is remembered across sessions and cleared when the torrent is deleted
+- Multi-language subtitle support — automatically detects `.srt` files and provides a language selector in the player UI
 - Pause, resume, and delete torrents (with optional file removal)
 - Persistent sessions — resume data is saved on `onStop` and restored on next launch
 - Share `.torrent` files to other clients via the system share sheet
@@ -24,9 +25,9 @@ https://github.com/user-attachments/assets/6182efdb-9862-47ee-9fa7-011a64ee87eb
 
 ## Screenshots
 
-| Torrent list with file list expanded and active download |
-|---|
-| <img src="screenshots/main.png" width="320" alt="Torrent list: Big Buck Bunny seeding with file list expanded showing Play button on the mp4, Sintel seeding, and Cosmos Laundromat downloading at 2.9 MB/s with 25 peers, ETA and ratio"> |
+| Torrent list with file list expanded and active download | ExoPlayer with multi-language subtitles |
+|---|---|
+| <img src="screenshots/main.png" width="320" alt="Torrent list: Big Buck Bunny seeding with file list expanded showing Play button on the mp4, Sintel seeding, and Cosmos Laundromat downloading at 2.9 MB/s with 25 peers, ETA and ratio"> | <img src="screenshots/player_subtitles.png" width="320" alt="Video playback in fullscreen with German subtitles displayed. Subtitle selector dropdown open on the right showing language options: None, German, English, Spanish, French, Italian, Dutch"> |
 
 ## Technical Stack
 
@@ -71,7 +72,7 @@ SimpleTorrent/
 │   │       │   ├── MainScreen.kt       # Compose UI: cards, piece map, file list, peer list
 │   │       │   └── MainScreenViewModel.kt
 │   │       └── player/
-│   │           └── PlayerScreen.kt     # ExoPlayer fullscreen player; position saved per file path
+│   │           └── PlayerScreen.kt     # ExoPlayer fullscreen player; position saved per file path; auto-detects and loads multi-language subtitles
 │   └── res/
 │       ├── drawable/               # Adaptive icon (vector magnet)
 │       └── xml/file_provider_paths.xml

app/src/main/java/com/jpcottin/simpletorrent/ui/player/PlayerScreen.kt

@@ -11,7 +11,10 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.safeDrawing
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.filled.ClosedCaption
 import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.runtime.Composable
@@ -38,6 +41,7 @@ import androidx.media3.exoplayer.ExoPlayer
 import androidx.media3.ui.PlayerView
 import com.jpcottin.simpletorrent.theme.SimpleTorrentTheme
 import java.io.File
+import java.util.Locale
 
 @androidx.annotation.OptIn(UnstableApi::class)
 @Composable
@@ -47,11 +51,40 @@ fun PlayerScreen(filePath: String, title: String, onBack: () -> Unit) {
     val isPreview = LocalInspectionMode.current
     val prefs = remember { context.getSharedPreferences("player_positions", Context.MODE_PRIVATE) }
     var isBuffering by remember { mutableStateOf(true) }
+    var showSubtitleMenu by remember { mutableStateOf(false) }
+    var subtitles by remember { mutableStateOf<List<Pair<String, String>>>(emptyList()) }
 
     val player = remember {
         if (isPreview) return@remember null
+        val videoFile = File(filePath)
+        val videoDir = videoFile.parentFile
+        val baseNameNoExt = videoFile.nameWithoutExtension
+
+        // Find all .srt files in the same directory
+        val srtConfigs = videoDir?.listFiles { file ->
+            file.isFile && file.extension == "srt"
+        }?.mapNotNull { srtFile ->
+            // Extract language code from filename pattern: *_xx.srt or subtitle_xx.srt
+            val match = Regex("([a-z]{2})\\.srt$").find(srtFile.name)
+            if (match != null) {
+                val languageCode = match.groupValues[1]
+                val displayLanguage = Locale(languageCode).displayLanguage
+                subtitles = subtitles + (languageCode to displayLanguage)
+                MediaItem.SubtitleConfiguration.Builder(Uri.fromFile(srtFile))
+                    .setMimeType("application/x-subrip")
+                    .setLanguage(languageCode)
+                    .setLabel(displayLanguage)
+                    .build()
+            } else null
+        } ?: emptyList()
+
         ExoPlayer.Builder(context).build().apply {
-            setMediaItem(MediaItem.fromUri(Uri.fromFile(File(filePath))))
+            val mediaItem = MediaItem.Builder()
+                .setUri(Uri.fromFile(videoFile))
+                .setSubtitleConfigurations(srtConfigs)
+                .build()
+
+            setMediaItem(mediaItem)
             prepare()
             val savedPosition = prefs.getLong(filePath, 0L)
             if (savedPosition > 0L) seekTo(savedPosition)
@@ -131,6 +164,46 @@ fun PlayerScreen(filePath: String, title: String, onBack: () -> Unit) {
                 tint = Color.White,
             )
         }
+        if (subtitles.isNotEmpty() && player != null) {
+            Box(
+                modifier = Modifier
+                    .align(Alignment.TopEnd)
+                    .padding(WindowInsets.safeDrawing.asPaddingValues()),
+            ) {
+                IconButton(onClick = { showSubtitleMenu = !showSubtitleMenu }) {
+                    Icon(
+                        Icons.Default.ClosedCaption,
+                        contentDescription = "Subtitles",
+                        tint = Color.White,
+                    )
+                }
+                DropdownMenu(
+                    expanded = showSubtitleMenu,
+                    onDismissRequest = { showSubtitleMenu = false },
+                ) {
+                    DropdownMenuItem(
+                        text = { Text("None") },
+                        onClick = {
+                            player.trackSelectionParameters = player.trackSelectionParameters.buildUpon()
+                                .setPreferredTextLanguages()
+                                .build()
+                            showSubtitleMenu = false
+                        },
+                    )
+                    subtitles.forEach { (languageCode, language) ->
+                        DropdownMenuItem(
+                            text = { Text(language) },
+                            onClick = {
+                                player.trackSelectionParameters = player.trackSelectionParameters.buildUpon()
+                                    .setPreferredTextLanguages(languageCode)
+                                    .build()
+                                showSubtitleMenu = false
+                            },
+                        )
+                    }
+                }
+            }
+        }
     }
 }