ANDROID: updated back-key handling to avoid potential double action

Author: Chris Warren-Smith

README.md

@@ -9,7 +9,7 @@ SmallBASIC is a fast and easy to learn BASIC language interpreter ideal for ever
 Ubuntu
 
 ```
-sudo apt-get install git autotools-dev automake gcc g++ libsdl2-dev libfreetype6-dev libfontconfig1-dev xxd
+sudo apt-get install git autotools-dev automake gcc g++ libsdl2-dev libfreetype6-dev libfontconfig1-dev xxd make
 ```
 
 Manjaro (Arch)

images/keypad/build.sh renamed to keypad/build.sh

@@ -35,5 +35,5 @@ do
     xxd -n img_${imageFile} -i ${imageFile}.png  >> keypad_icons.h
 done
 
-mv keypad_icons.h ../../src/ui
+mv keypad_icons.h ../src/ui
 

src/platform/android/app/src/main/java/net/sourceforge/smallbasic/MainActivity.java

@@ -429,6 +429,10 @@ public int getWindowHeight() {
     return rect.height();
   }
 
+  public boolean isPredictiveBack() {
+    return Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU;
+  }
+
   public boolean loadModules() {
     Log.i(TAG, "loadModules: " + getActivity());
     boolean result;
@@ -1063,7 +1067,7 @@ private void setImmersiveMode() {
   // Hook into Predictive Back (Android 13+)
   //
   private void setupPredictiveBack() {
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+    if (isPredictiveBack()) {
       getOnBackInvokedDispatcher().registerOnBackInvokedCallback(
           OnBackInvokedDispatcher.PRIORITY_DEFAULT,
           new OnBackInvokedCallback() {

src/platform/android/build.gradle

@@ -5,7 +5,7 @@ buildscript {
     mavenCentral()
   }
   dependencies {
-    classpath 'com.android.tools.build:gradle:8.11.1'
+    classpath 'com.android.tools.build:gradle:8.12.0'
   }
 }
 

src/platform/android/jni/runtime.cpp

@@ -33,6 +33,9 @@ Runtime *runtime = nullptr;
 // Pipe file descriptors: g_backPipe[0] is read-end, g_backPipe[1] is write-end
 static int g_backPipe[2] = {-1, -1};
 
+// whether native back key handling is active
+static bool g_predictiveBack = false;
+
 // the sensorTypes corresponding to _sensors[] positions
 constexpr int SENSOR_TYPES[MAX_SENSORS] = {
   ASENSOR_TYPE_ACCELEROMETER,
@@ -159,7 +162,7 @@ static void process_input(android_app *app, android_poll_source *source) {
         AKeyEvent_getKeyCode(event) == AKEYCODE_BACK) {
       // prevent AInputQueue_preDispatchEvent from attempting to close
       // the keypad here to avoid a crash in android 4.2 + 4.3.
-      if (AKeyEvent_getAction(event) == AKEY_EVENT_ACTION_DOWN && runtime->isActive()) {
+      if (AKeyEvent_getAction(event) == AKEY_EVENT_ACTION_DOWN && runtime->isActive() && !g_predictiveBack) {
         pushBackEvent();
       }
       AInputQueue_finishEvent(app->inputQueue, event, true);
@@ -287,7 +290,10 @@ Runtime::Runtime(android_app *app) :
   _looper = ALooper_forThread();
   _sensorManager = ASensorManager_getInstance();
   memset(&_sensors, 0, sizeof(_sensors));
-  setupBackWakePipe(_looper);
+  g_predictiveBack = getBoolean("isPredictiveBack");
+  if (g_predictiveBack) {
+    setupBackWakePipe(_looper);
+  }
 }
 
 Runtime::~Runtime() {