Implement DoAllPlayersHaveGame() check

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/netplay/NetplaySession.kt

@@ -170,6 +170,8 @@ class NetplaySession(
 
     fun changeGame(gameFile: GameFile) = nativeChangeGame(gameFile)
 
+    fun doAllPlayersHaveGame(): Boolean = nativeDoAllPlayersHaveGame()
+
     fun startGame() = nativeStartGame()
 
     fun getPort(): Int = nativeGetPort()
@@ -261,6 +263,8 @@ class NetplaySession(
 
     private external fun nativeChangeGame(gameFile: GameFile)
 
+    private external fun nativeDoAllPlayersHaveGame(): Boolean
+
     private external fun nativeStartGame()
 
     private external fun nativeGetPort(): Int

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/netplay/model/NetplayViewModel.kt

@@ -9,7 +9,9 @@ import androidx.lifecycle.viewModelScope
 import kotlinx.coroutines.DelicateCoroutinesApi
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.launchIn
@@ -99,7 +101,18 @@ class NetplayViewModel(
         }
     }
 
+    private val _notAllPlayersHaveGame = Channel<Unit>(Channel.CONFLATED)
+    val notAllPlayersHaveGame = _notAllPlayersHaveGame.receiveAsFlow()
+
     fun startGame() {
+        if (netplaySession.doAllPlayersHaveGame()) {
+            netplaySession.startGame()
+        } else {
+            _notAllPlayersHaveGame.trySend(Unit)
+        }
+    }
+
+    fun confirmStartGame() {
         netplaySession.startGame()
     }
 

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/netplay/ui/NetplayActivity.kt

@@ -9,7 +9,6 @@ import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.appcompat.app.AppCompatActivity
 import androidx.compose.runtime.collectAsState
-import androidx.compose.runtime.livedata.observeAsState
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.flowWithLifecycle
@@ -49,15 +48,17 @@ class NetplayActivity : AppCompatActivity(), ThemeProvider {
             DolphinTheme {
                 NetplayScreen(
                     onBackClicked = { finish() },
+                    isHosting = viewModel.isHosting,
                     connectionLost = viewModel.connectionLost,
                     fatalTraversalError = viewModel.fatalTraversalError,
                     messages = viewModel.messages.collectAsState().value,
                     onSendMessage = viewModel::sendMessage,
                     game = viewModel.game.collectAsState().value,
-                    isHosting = viewModel.isHosting,
                     onStartGame = viewModel::startGame,
                     onGameSelected = viewModel::changeGame,
                     gameFiles = viewModel.gameFiles.collectAsState().value,
+                    notAllPlayersHaveGame = viewModel.notAllPlayersHaveGame,
+                    onConfirmStartGame = viewModel::confirmStartGame,
                     players = viewModel.players.collectAsState().value,
                     hostInputAuthorityEnabled = viewModel.hostInputAuthority.collectAsState().value,
                     networkMode = viewModel.networkMode.collectAsState().value,

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/features/netplay/ui/NetplayScreen.kt

@@ -121,6 +121,8 @@ fun NetplayScreen(
     onStartGame: () -> Unit,
     onGameSelected: (GameFile) -> Unit,
     gameFiles: List<GameFile>,
+    notAllPlayersHaveGame: Flow<Unit>,
+    onConfirmStartGame: () -> Unit,
     hostInputAuthorityEnabled: Boolean,
     networkMode: NetworkMode,
     onNetworkModeChanged: (NetworkMode) -> Unit,
@@ -229,6 +231,11 @@ fun NetplayScreen(
             fatalTraversalError.collect { traversalError = it }
         }
 
+        var showNotAllPlayersHaveGame by rememberSaveable { mutableStateOf(false) }
+        LaunchedEffect(Unit) {
+            notAllPlayersHaveGame.collect { showNotAllPlayersHaveGame = true }
+        }
+
         var dismissSaveTransferProgressDialog by rememberSaveable { mutableStateOf(false) }
         if (saveTransferProgress == null) {
             dismissSaveTransferProgressDialog = false
@@ -279,6 +286,27 @@ fun NetplayScreen(
                     onDismiss = { dismissGameDigestDialog = true },
                 )
             }
+
+            showNotAllPlayersHaveGame -> {
+                AlertDialog(
+                    title = { Text(stringResource(R.string.netplay_start_warning_title)) },
+                    text = { Text(stringResource(R.string.netplay_start_warning_not_all_players_have_game)) },
+                    confirmButton = {
+                        TextButton(onClick = {
+                            showNotAllPlayersHaveGame = false
+                            onConfirmStartGame()
+                        }) {
+                            Text(stringResource(R.string.yes))
+                        }
+                    },
+                    dismissButton = {
+                        TextButton(onClick = { showNotAllPlayersHaveGame = false }) {
+                            Text(stringResource(R.string.no))
+                        }
+                    },
+                    onDismissRequest = { showNotAllPlayersHaveGame = false },
+                )
+            }
         }
     }
 }
@@ -1280,6 +1308,8 @@ private fun PreviewNetplayScreen() {
         onStartGame = {},
         onGameSelected = {},
         gameFiles = emptyList(),
+        notAllPlayersHaveGame = emptyFlow(),
+        onConfirmStartGame = {},
         hostInputAuthorityEnabled = true,
         networkMode = NetworkMode.HOST_INPUT_AUTHORITY,
         onNetworkModeChanged = {},

Source/Android/app/src/main/res/values/strings.xml

@@ -997,6 +997,8 @@ It can efficiently compress both junk data and encrypted Wii data.
     <string name="netplay_port_label">Port</string>
     <string name="netplay_title">Netplay</string>
     <string name="netplay_start">Start</string>
+    <string name="netplay_start_warning_title">Warning</string>
+    <string name="netplay_start_warning_not_all_players_have_game">Not all players have the game. Do you really want to start?</string>
     <string name="netplay_chat_label">Chat</string>
     <string name="netplay_chat_send">Send</string>
     <string name="netplay_message_game_changed">Game changed to %1$s</string>

Source/Android/jni/NetPlay/Netplay.cpp

@@ -181,6 +181,15 @@ Java_org_dolphinemu_dolphinemu_features_netplay_NetplaySession_nativeChangeGame(
   server->ChangeGame(game_file->GetSyncIdentifier(), game_file->GetLongName());
 }
 
+JNIEXPORT jboolean JNICALL
+Java_org_dolphinemu_dolphinemu_features_netplay_NetplaySession_nativeDoAllPlayersHaveGame(
+    JNIEnv* env, jobject obj)
+{
+  if (auto* client = GetClientPointer(env, obj))
+    return static_cast<jboolean>(client->DoAllPlayersHaveGame());
+  return JNI_TRUE;
+}
+
 JNIEXPORT void JNICALL
 Java_org_dolphinemu_dolphinemu_features_netplay_NetplaySession_nativeStartGame(JNIEnv* env,
                                                                           jobject obj)