On Android, calling Platform.exit() should result in closing the Activity. At this moment, the render thread is stopped but the Activity is still active, resulting in a black sceen.
The following patch registers a FinishListener with the PlatformImpl, and on callback this listener will finish the Android activity:
diff -r 92fcf0f1d66d modules/graphics/src/dalvik/java/javafxports/android/DalvikLauncher.java
--- a/modules/graphics/src/dalvik/java/javafxports/android/DalvikLauncher.java Wed Nov 26 11:29:59 2014 +0100
+++ b/modules/graphics/src/dalvik/java/javafxports/android/DalvikLauncher.java Fri Nov 28 10:03:06 2014 +0100
@@ -37,6 +37,8 @@
 import java.lang.reflect.Method;
 import java.util.Map.Entry;
 import java.util.Properties;
+import com.sun.javafx.application.PlatformImpl;
+import com.sun.javafx.application.PlatformImpl.FinishListener;
 
 public class DalvikLauncher implements Launcher {
 
@@ -175,8 +177,24 @@
         FXActivity.getInstance().setOnSurfaceChangedNativeMethod2(dalvikInputClass.getMethod("onSurfaceChangedNative", int.class, int.class, int.class));
         FXActivity.getInstance().setOnSurfaceRedrawNeededNativeMethod(dalvikInputClass.getMethod("onSurfaceRedrawNeededNative"));
         FXActivity.getInstance().setOnConfigurationChangedNativeMethod(dalvikInputClass.getMethod("onConfigurationChangedNative", int.class));
+ registerExitListener();
     }
 
+ private void registerExitListener() {
+ FinishListener l = new FinishListener() {
+ public void idle(boolean implicitExit) {
+ Log.v (TAG, "FinishListener idle called with exit = "+implicitExit);
+ activity.finish();
+ }
+ public void exitCalled() {
+ Log.v (TAG, "FinishListener exit called");
+ activity.finish();
+ }
+ };
+ PlatformImpl.addListener(l);
+ }
+
+
     private Class resolveApplicationClass()
             throws PackageManager.NameNotFoundException, ClassNotFoundException {