sugest to reuse architecture direct golang instead of add java code ...

internal/driver/mobile/app/android.c

@@ -66,6 +66,25 @@ jint JNI_OnLoad(JavaVM* vm, void* reserved) {
 
 static int main_running = 0;
 
+void set_global(ANativeActivity *activity){
+	JNIEnv* env = activity->env;
+    // Note that activity->clazz is mis-named.
+    current_class = (*env)->GetObjectClass(env, activity->clazz);
+	current_class = (*env)->NewGlobalRef(env, current_class);
+	key_rune_method = find_static_method(env, current_class, "getRune", "(III)I");
+	show_keyboard_method = find_static_method(env, current_class, "showKeyboard", "(I)V");
+	hide_keyboard_method = find_static_method(env, current_class, "hideKeyboard", "()V");
+	show_file_open_method = find_static_method(env, current_class, "showFileOpen", "(Ljava/lang/String;)V");
+	show_file_save_method = find_static_method(env, current_class, "showFileSave", "(Ljava/lang/String;Ljava/lang/String;)V");
+	finish_method = find_method(env, current_class, "finish", "()V");
+
+	setCurrentContext(activity->vm, (*env)->NewGlobalRef(env, activity->clazz));
+}
+
+void delete_ref(ANativeActivity *activity){
+	(*env)->DeleteGlobalRef(activity->env, current_class);
+}
+
 // Entry point from our subclassed NativeActivity.
 //
 // By here, the Go runtime has been initialized (as we are running in
@@ -78,17 +97,7 @@ void ANativeActivity_onCreate(ANativeActivity *activity, void* savedState, size_
 	if (!main_running) {
 		JNIEnv* env = activity->env;
 
-		// Note that activity->clazz is mis-named.
-		current_class = (*env)->GetObjectClass(env, activity->clazz);
-		current_class = (*env)->NewGlobalRef(env, current_class);
-		key_rune_method = find_static_method(env, current_class, "getRune", "(III)I");
-		show_keyboard_method = find_static_method(env, current_class, "showKeyboard", "(I)V");
-		hide_keyboard_method = find_static_method(env, current_class, "hideKeyboard", "()V");
-		show_file_open_method = find_static_method(env, current_class, "showFileOpen", "(Ljava/lang/String;)V");
-		show_file_save_method = find_static_method(env, current_class, "showFileSave", "(Ljava/lang/String;Ljava/lang/String;)V");
-		finish_method = find_method(env, current_class, "finishActivity", "()V");
-
-		setCurrentContext(activity->vm, (*env)->NewGlobalRef(env, activity->clazz));
+		set_global(activity);
 
 		// Set FILESDIR
 		if (setenv("FILESDIR", activity->internalDataPath, 1) != 0) {
@@ -160,6 +169,13 @@ static char* initEGLDisplay() {
 	return NULL;
 }
 
+void finish(JNIEnv* env, jobject ctx) {
+    (*env)->CallVoidMethod(
+        env,
+        ctx,
+        finish_method);
+}
+
 char* createEGLSurface(ANativeWindow* window) {
 	char* err;
 	EGLint numConfigs, format;
@@ -206,13 +222,6 @@ char* destroyEGLSurface() {
 	return NULL;
 }
 
-void finish(JNIEnv* env, jobject ctx) {
-    (*env)->CallVoidMethod(
-        env,
-        ctx,
-        finish_method);
-}
-
 int32_t getKeyRune(JNIEnv* env, AInputEvent* e) {
 	return (int32_t)(*env)->CallStaticIntMethod(
 		env,
@@ -281,10 +290,6 @@ void Java_org_golang_app_GoNativeActivity_keyboardDelete(JNIEnv *env, jclass cla
     keyboardDelete();
 }
 
-void Java_org_golang_app_GoNativeActivity_backPressed(JNIEnv *env, jclass clazz) {
-    onBackPressed();
-}
-
 void Java_org_golang_app_GoNativeActivity_setDarkMode(JNIEnv *env, jclass clazz, jboolean dark) {
     setDarkMode((bool)dark);
 }

internal/driver/mobile/app/android.go

@@ -49,6 +49,8 @@ void hideKeyboard(JNIEnv* env);
 void showFileOpen(JNIEnv* env, char* mimes);
 void showFileSave(JNIEnv* env, char* mimes, char* filename);
 void finish(JNIEnv* env, jobject ctx);
+void set_global(ANativeActivity *activity);
+void delete_ref(ANativeActivity *activity);
 
 void Java_org_golang_app_GoNativeActivity_filePickerReturned(JNIEnv *env, jclass clazz, jstring str);
 */
@@ -78,18 +80,6 @@ var mimeMap = map[string]string{
 	".txt": "text/plain",
 }
 
-// GoBack asks the OS to go to the previous app / activity
-func GoBack() {
-	err := RunOnJVM(func(_, jniEnv, ctx uintptr) error {
-		env := (*C.JNIEnv)(unsafe.Pointer(jniEnv))
-		C.finish(env, C.jobject(ctx))
-		return nil
-	})
-	if err != nil {
-		log.Fatalf("app: %v", err)
-	}
-}
-
 // RunOnJVM runs fn on a new goroutine locked to an OS thread with a JNIEnv.
 //
 // RunOnJVM blocks until the call to fn is complete. Any Java
@@ -133,10 +123,12 @@ func callMain(mainPC uintptr) {
 
 //export onStart
 func onStart(activity *C.ANativeActivity) {
+	C.set_global(activity)
 }
 
 //export onResume
 func onResume(activity *C.ANativeActivity) {
+	C.set_global(activity)
 }
 
 //export onSaveInstanceState
@@ -146,23 +138,12 @@ func onSaveInstanceState(activity *C.ANativeActivity, outSize *C.size_t) unsafe.
 
 //export onPause
 func onPause(activity *C.ANativeActivity) {
+	C.delete_ref(activity)
 }
 
 //export onStop
 func onStop(activity *C.ANativeActivity) {
-}
-
-//export onBackPressed
-func onBackPressed() {
-	k := key.Event{
-		Code:      key.CodeBackButton,
-		Direction: key.DirPress,
-	}
-	log.Println("Logging key event back")
-	theApp.events.In() <- k
-
-	k.Direction = key.DirRelease
-	theApp.events.In() <- k
+	C.delete_ref(activity)
 }
 
 //export onCreate
@@ -177,6 +158,7 @@ func onCreate(activity *C.ANativeActivity) {
 
 //export onDestroy
 func onDestroy(activity *C.ANativeActivity) {
+	C.delete_ref(activity)
 	activityDestroyed <- struct{}{}
 }
 
@@ -230,6 +212,14 @@ type windowConfig struct {
 	pixelsPerPt float32
 }
 
+func Finish() {
+	RunOnJVM(func(vm, jniEnv, ctx uintptr) error {
+		println("finish")
+		env := (*C.JNIEnv)(unsafe.Pointer(jniEnv)) // not a Go heap pointer
+		C.finish(env, C.jobject(ctx))
+		return nil
+	})
+}
 func windowConfigRead(activity *C.ANativeActivity) windowConfig {
 	aconfig := C.AConfiguration_new()
 	C.AConfiguration_fromAssetManager(aconfig, activity.assetManager)
@@ -555,21 +545,22 @@ func runInputQueue(vm, jniEnv, ctx uintptr) error {
 	}
 }
 
+
 func processEvents(env *C.JNIEnv, q *C.AInputQueue) {
 	var e *C.AInputEvent
 	for C.AInputQueue_getEvent(q, &e) >= 0 {
 		if C.AInputQueue_preDispatchEvent(q, e) != 0 {
 			continue
 		}
-		processEvent(env, e)
-		C.AInputQueue_finishEvent(q, e, 0)
+		handle := processEvent(env, e)
+		C.AInputQueue_finishEvent(q, e, C.int(handle))
 	}
 }
 
-func processEvent(env *C.JNIEnv, e *C.AInputEvent) {
+func processEvent(env *C.JNIEnv, e *C.AInputEvent) int {
 	switch C.AInputEvent_getType(e) {
 	case C.AINPUT_EVENT_TYPE_KEY:
-		processKey(env, e)
+		return processKey(env, e)
 	case C.AINPUT_EVENT_TYPE_MOTION:
 		// At most one of the events in this batch is an up or down event; get its index and change.
 		upDownIndex := C.size_t(C.AMotionEvent_getAction(e)&C.AMOTION_EVENT_ACTION_POINTER_INDEX_MASK) >> C.AMOTION_EVENT_ACTION_POINTER_INDEX_SHIFT
@@ -596,21 +587,28 @@ func processEvent(env *C.JNIEnv, e *C.AInputEvent) {
 	default:
 		log.Printf("unknown input event, type=%d", C.AInputEvent_getType(e))
 	}
+	return 0
 }
 
-func processKey(env *C.JNIEnv, e *C.AInputEvent) {
+func processKey(env *C.JNIEnv, e *C.AInputEvent) int {
 	deviceID := C.AInputEvent_getDeviceId(e)
 	if deviceID == 0 {
 		// Software keyboard input, leaving for scribe/IME.
-		return
+		return 0
+	}
+	keyCode := C.AKeyEvent_getKeyCode(e)
+	if (keyCode == C.AKEYCODE_BACK) {
+		println("back ok")
+		return 1 // Handle back button press and return handle
+	} else if (keyCode == C.AKEYCODE_MENU) {
+		return 1 // Handle menu button press
 	}
-
 	k := key.Event{
 		Rune: rune(C.getKeyRune(env, e)),
-		Code: convAndroidKeyCode(int32(C.AKeyEvent_getKeyCode(e))),
+		Code: convAndroidKeyCode(int32(keyCode)),
 	}
 	if k.Rune >= '0' && k.Rune <= '9' { // GBoard generates key events for numbers, but we see them in textChanged
-		return
+		return 0
 	}
 	switch C.AKeyEvent_getAction(e) {
 	case C.AKEY_STATE_DOWN:
@@ -621,7 +619,8 @@ func processKey(env *C.JNIEnv, e *C.AInputEvent) {
 		k.Direction = key.DirNone
 	}
 	// TODO(crawshaw): set Modifiers.
-	theApp.events.In() <- k
+	go func() {theApp.events.In() <- k}()
+	return 0
 }
 
 func eglGetError() string {

internal/driver/mobile/app/darwin_desktop.go

@@ -63,10 +63,6 @@ func main(f func(App)) {
 	C.runApp()
 }
 
-func GoBack() {
-	// When simulating mobile there are no other activities open (and we can't just force background)
-}
-
 // loop is the primary drawing loop.
 //
 // After Cocoa has captured the initial OS thread for processing Cocoa
@@ -107,7 +103,9 @@ func (a *app) loop(ctx C.GLintptr) {
 		}
 	}
 }
+func Finish() {
 
+}
 var drawDone = make(chan struct{})
 
 // drawgl is used by Cocoa to occasionally request screen updates.

internal/driver/mobile/app/darwin_ios.go

@@ -82,10 +82,6 @@ var DisplayMetrics struct {
 	HeightPx int
 }
 
-func GoBack() {
-	// Apple do not permit apps to exit in any way other than user pressing home button / gesture
-}
-
 //export setDisplayMetrics
 func setDisplayMetrics(width, height int, scale int) {
 	DisplayMetrics.WidthPx = width
@@ -150,7 +146,9 @@ func updateConfig(width, height, orientation int32) {
 	}
 	theApp.events.In() <- paint.Event{External: true}
 }
+func Finish() {
 
+}
 // touchIDs is the current active touches. The position in the array
 // is the ID, the value is the UITouch* pointer value.
 //

internal/driver/mobile/app/x11.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build (linux && !android) || freebsd
-// +build linux,!android freebsd
+//go:build linux && !android
+// +build linux,!android
 
 package app
 
@@ -15,7 +15,6 @@ than screens with touch panels.
 
 /*
 #cgo LDFLAGS: -lEGL -lGLESv2 -lX11
-#cgo freebsd CFLAGS: -I/usr/local/include/
 
 void createWindow(void);
 void processEvents(void);
@@ -79,11 +78,9 @@ func main(f func(App)) {
 		}
 	}
 }
+func Finish() {
 
-func GoBack() {
-	// When simulating mobile there are no other activities open (and we can't just force background)
 }
-
 //export onResize
 func onResize(w, h int) {
 	// TODO(nigeltao): don't assume 72 DPI. DisplayWidth and DisplayWidthMM