[Android] Fix handling of back navigation when targeting API level 36

platform/android/java/app/src/androidTestInstrumented/java/com/godot/game/GodotAppTest.kt

@@ -34,8 +34,11 @@ import android.content.ComponentName
 import android.content.Intent
 import android.util.Log
 import androidx.test.core.app.ActivityScenario
+import androidx.test.espresso.Espresso
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
 import com.godot.game.test.GodotAppInstrumentedTestPlugin
+import org.godotengine.godot.Godot
 import org.godotengine.godot.GodotActivity.Companion.EXTRA_COMMAND_LINE_PARAMS
 import org.godotengine.godot.plugin.GodotPluginRegistry
 import org.junit.Test
@@ -169,4 +172,56 @@ class GodotAppTest {
 			}
 		}
 	}
+
+	/**
+	 * Validate that the back press does not quit the game when 'quit_on_go_back' is disabled.
+	 */
+	@Test
+	fun testGameNotQuittingOnBackPress() {
+		ActivityScenario.launch(GodotApp::class.java).use { scenario ->
+			val testPlugin = getTestPlugin()
+			assertNotNull(testPlugin)
+
+			Log.d(TAG, "Waiting for the Godot main loop to start...")
+			testPlugin.waitForGodotMainLoopStarted()
+
+			// Disable 'quit_on_go_back'.
+			testPlugin.updateQuitOnGoBack(false)
+
+			// Trigger the back press event.
+			Espresso.pressBackUnconditionally()
+
+			Log.d(TAG, "Waiting for the engine to terminate...")
+			testPlugin.waitForEngineTermination(5_000L)
+
+			val godot = Godot.getInstance(InstrumentationRegistry.getInstrumentation().targetContext)
+			assertTrue { godot.runStatus != Godot.RunStatus.TERMINATING }
+		}
+	}
+
+	/**
+	 * Validate that the back press event quits the game when 'quit_on_go_back' is enabled.
+	 */
+	@Test
+	fun testGameQuittingOnBackPress() {
+		ActivityScenario.launch(GodotApp::class.java).use { scenario ->
+			val testPlugin = getTestPlugin()
+			assertNotNull(testPlugin)
+
+			Log.d(TAG, "Waiting for the Godot main loop to start...")
+			testPlugin.waitForGodotMainLoopStarted()
+
+			// Enable 'quit_on_go_back'.
+			testPlugin.updateQuitOnGoBack(true)
+
+			// Trigger the back press event.
+			Espresso.pressBackUnconditionally()
+
+			Log.d(TAG, "Waiting for the engine to terminate...")
+			testPlugin.waitForEngineTermination(5_000L)
+
+			val godot = Godot.getInstance(InstrumentationRegistry.getInstrumentation().targetContext)
+			assertTrue { godot.runStatus == Godot.RunStatus.TERMINATING }
+		}
+	}
 }

platform/android/java/app/src/instrumented/assets/main.gd

@@ -7,6 +7,7 @@ func _ready():
 	if Engine.has_singleton(_plugin_name):
 		_android_plugin = Engine.get_singleton(_plugin_name)
 		_android_plugin.connect("launch_tests", _launch_tests)
+		_android_plugin.connect("update_quit_on_go_back", _update_quit_on_go_back)
 	else:
 		printerr("Couldn't find plugin " + _plugin_name)
 		get_tree().quit()
@@ -28,6 +29,10 @@ func _launch_tests(test_label: String) -> void:
 		_android_plugin.onTestsFailed(test_label, "Unable to launch tests")
 
 
+func _update_quit_on_go_back(quit_on_go_back: bool) -> void:
+	get_tree().quit_on_go_back = quit_on_go_back
+
+
 func _on_plugin_toast_button_pressed() -> void:
 	if _android_plugin:
 		_android_plugin.helloWorld()

platform/android/java/app/src/instrumented/assets/test/file_access/file_access_tests.gd

@@ -12,7 +12,7 @@ func run_tests():
 
 	# Scoped storage: Testing access to Downloads and Documents directory.
 	var version = JavaClassWrapper.wrap("android.os.Build$VERSION")
-	if version.SDK_INT >= 29:
+	if version.SDK_INT >= 30:
 		__exec_test(test_downloads_dir_access)
 		__exec_test(test_documents_dir_access)
 

platform/android/java/app/src/instrumented/java/com/godot/game/test/GodotAppInstrumentedTestPlugin.kt

@@ -38,6 +38,7 @@ import org.godotengine.godot.plugin.UsedByGodot
 import org.godotengine.godot.plugin.SignalInfo
 import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
 
 /**
  * [GodotPlugin] used to drive instrumented tests.
@@ -47,14 +48,17 @@ class GodotAppInstrumentedTestPlugin(godot: Godot) : GodotPlugin(godot) {
 	companion object {
 		private val TAG = GodotAppInstrumentedTestPlugin::class.java.simpleName
 		private const val MAIN_LOOP_STARTED_LATCH_KEY = "main_loop_started_latch"
+		private const val ENGINE_TERMINATING_LATCH_KEY = "engine_terminating_latch"
 
 		private const val JAVACLASSWRAPPER_TESTS = "javaclasswrapper_tests"
 		private const val FILE_ACCESS_TESTS = "file_access_tests"
 
 		private val LAUNCH_TESTS_SIGNAL = SignalInfo("launch_tests", String::class.java)
+		private val UPDATE_QUIT_ON_GO_BACK_SIGNAL = SignalInfo("update_quit_on_go_back", java.lang.Boolean::class.java)
 
 		private val SIGNALS = setOf(
-			LAUNCH_TESTS_SIGNAL
+			LAUNCH_TESTS_SIGNAL,
+			UPDATE_QUIT_ON_GO_BACK_SIGNAL
 		)
 	}
 
@@ -65,6 +69,8 @@ class GodotAppInstrumentedTestPlugin(godot: Godot) : GodotPlugin(godot) {
 		// Add a countdown latch that is triggered when `onGodotMainLoopStarted` is fired.
 		// This will be used by tests to wait until the engine is ready.
 		latches[MAIN_LOOP_STARTED_LATCH_KEY] = CountDownLatch(1)
+		// Add a countdown latch that is triggered when the engine terminates.
+		latches[ENGINE_TERMINATING_LATCH_KEY] = CountDownLatch(1)
 	}
 
 	override fun getPluginName() = "GodotAppInstrumentedTestPlugin"
@@ -76,6 +82,11 @@ class GodotAppInstrumentedTestPlugin(godot: Godot) : GodotPlugin(godot) {
 		latches.remove(MAIN_LOOP_STARTED_LATCH_KEY)?.countDown()
 	}
 
+	override fun onGodotTerminating() {
+		super.onGodotTerminating()
+		latches.remove(ENGINE_TERMINATING_LATCH_KEY)?.countDown()
+	}
+
 	/**
 	 * Used by the instrumented test to wait until the Godot main loop is up and running.
 	 */
@@ -88,6 +99,19 @@ class GodotAppInstrumentedTestPlugin(godot: Godot) : GodotPlugin(godot) {
 		}
 	}
 
+	internal fun waitForEngineTermination(timeoutInMs: Long) {
+		// Wait on the CountDownLatch for `onGodotTerminating`.
+		try {
+			latches[ENGINE_TERMINATING_LATCH_KEY]?.await(timeoutInMs, TimeUnit.MILLISECONDS)
+		} catch (e: InterruptedException) {
+			Log.e(TAG, "Unable to wait for engine termination event.", e)
+		}
+	}
+
+	internal fun updateQuitOnGoBack(quitOnGoBack: Boolean) {
+		emitSignal(UPDATE_QUIT_ON_GO_BACK_SIGNAL, quitOnGoBack)
+	}
+
 	/**
 	 * This launches the JavaClassWrapper tests, and wait until the tests are complete before returning.
 	 */
@@ -104,7 +128,7 @@ class GodotAppInstrumentedTestPlugin(godot: Godot) : GodotPlugin(godot) {
 
 	private fun launchTests(testLabel: String): Result<Any>? {
 		val latch = latches.getOrPut(testLabel) { CountDownLatch(1) }
-		emitSignal(LAUNCH_TESTS_SIGNAL.name, testLabel)
+		emitSignal(LAUNCH_TESTS_SIGNAL, testLabel)
 		return try {
 			latch.await()
 			val result = testResults.remove(testLabel)

platform/android/java/lib/src/main/java/org/godotengine/godot/Godot.kt

@@ -122,6 +122,15 @@ class Godot private constructor(val context: Context) {
 		internal fun isEditorBuild() = BuildConfig.FLAVOR == EDITOR_FLAVOR
 	}
 
+	/**
+	 * Describes the engine current run status.
+	 */
+	enum class RunStatus {
+		INITIALIZING,
+		STARTED,
+		TERMINATING
+	}
+
 	private val mSensorManager: SensorManager? by lazy { context.getSystemService(Context.SENSOR_SERVICE) as? SensorManager }
 	private val mClipboard: ClipboardManager? by lazy { context.getSystemService(Context.CLIPBOARD_SERVICE) as? ClipboardManager }
 	private val vibratorService: Vibrator? by lazy { context.getSystemService(Context.VIBRATOR_SERVICE) as? Vibrator }
@@ -185,9 +194,11 @@ class Godot private constructor(val context: Context) {
 	private var resumed = false
 
 	/**
-	 * Tracks whether [onGodotSetupCompleted] fired.
+	 * Tracks the engine's run status.
 	 */
-	private val godotMainLoopStarted = AtomicBoolean(false)
+	private val _runStatus = AtomicReference<RunStatus>(RunStatus.INITIALIZING)
+	val runStatus: RunStatus
+		get() = _runStatus.get()
 
 	val io = GodotIO(this)
 
@@ -697,7 +708,7 @@ class Godot private constructor(val context: Context) {
 	}
 
 	private fun registerSensorsIfNeeded() {
-		if (!resumed || !godotMainLoopStarted.get()) {
+		if (!resumed || runStatus != RunStatus.STARTED) {
 			return
 		}
 
@@ -858,7 +869,7 @@ class Godot private constructor(val context: Context) {
 	 */
 	private fun onGodotMainLoopStarted() {
 		Log.v(TAG, "OnGodotMainLoopStarted")
-		godotMainLoopStarted.set(true)
+		_runStatus.set(RunStatus.STARTED)
 
 		accelerometerEnabled.set(java.lang.Boolean.parseBoolean(GodotLib.getGlobal("input_devices/sensors/enable_accelerometer")))
 		gravityEnabled.set(java.lang.Boolean.parseBoolean(GodotLib.getGlobal("input_devices/sensors/enable_gravity")))
@@ -881,6 +892,11 @@ class Godot private constructor(val context: Context) {
 	@Keep
 	private fun onGodotTerminating() {
 		Log.v(TAG, "OnGodotTerminating")
+		_runStatus.set(RunStatus.TERMINATING)
+
+		for (plugin in pluginRegistry.allPlugins) {
+			plugin.onGodotTerminating()
+		}
 		runOnTerminate.get()?.run()
 	}
 

platform/android/java/lib/src/main/java/org/godotengine/godot/GodotActivity.kt

@@ -41,6 +41,7 @@ import android.os.Bundle
 import android.util.Log
 import android.util.Rational
 import android.view.View
+import androidx.activity.addCallback
 import androidx.annotation.CallSuper
 import androidx.annotation.LayoutRes
 import androidx.fragment.app.FragmentActivity
@@ -54,7 +55,7 @@ import java.util.concurrent.atomic.AtomicReference
 /**
  * Base abstract activity for Android apps intending to use Godot as the primary screen.
  *
- * Also a reference implementation for how to setup and use the [GodotFragment] fragment
+ * Also a reference implementation for how to set up and use the [GodotFragment] fragment
  * within an Android app.
  */
 abstract class GodotActivity : FragmentActivity(), GodotHost, PictureInPictureProvider {
@@ -133,6 +134,9 @@ abstract class GodotActivity : FragmentActivity(), GodotHost, PictureInPicturePr
 
 		setContentView(getGodotAppLayout())
 
+		// Register `OnBackPressedCallback` for the Godot fragment.
+		onBackPressedDispatcher.addCallback { godotFragment?.onBackPressed() }
+
 		handleStartIntent(intent, true)
 
 		val currentFragment = supportFragmentManager.findFragmentById(R.id.godot_fragment_container)
@@ -283,10 +287,6 @@ abstract class GodotActivity : FragmentActivity(), GodotHost, PictureInPicturePr
 		}
 	}
 
-	override fun onBackPressed() {
-		godotFragment?.onBackPressed() ?: super.onBackPressed()
-	}
-
 	override fun getActivity(): Activity? {
 		return this
 	}

platform/android/java/lib/src/main/java/org/godotengine/godot/plugin/GodotPlugin.java

@@ -235,6 +235,11 @@ public abstract class GodotPlugin {
 	 */
 	public void onGodotMainLoopStarted() {}
 
+	/**
+	 * Invoked on the render thread when the Godot engine is terminating.
+	 */
+	public void onGodotTerminating() {}
+
 	/**
 	 * When using the OpenGL renderer, this is invoked once per frame on the GL thread after the
 	 * frame is drawn.
@@ -414,7 +419,7 @@ public abstract class GodotPlugin {
 				Object signalArg = signalArgs[i];
 				if (signalArg != null && !signalParamTypes[i].isInstance(signalArg)) {
 					throw new IllegalArgumentException(
-							"Invalid type for argument #" + i + ". Should be of type " + signalParamTypes[i].getName());
+							"Invalid type for argument #" + i + ". Should be of type '" + signalParamTypes[i].getName() + "' but is of type '" + signalArg.getClass().getName() + "'.");
 				}
 			}