android: bug fixes

onInputDeviceAdded may be called with an invalid device id. Avoid NPE
onGenericMotionEvent: event may have a null device. Avoid NPE
getExternalFilesDir may return null if no external storage available.
Use getFilesDir in this case.
Catch exceptions in HomeMover and continue.
addStorage: catch SecurityException and alert user. Graceful failure.

shell/android-studio/flycast/src/main/java/com/flycast/emulator/AndroidStorage.java

@@ -19,9 +19,11 @@
 package com.flycast.emulator;
 
 import android.app.Activity;
+import android.app.AlertDialog;
 import android.content.ContentResolver;
 import android.content.ContentUris;
 import android.content.CursorLoader;
+import android.content.DialogInterface;
 import android.content.Intent;
 import android.database.Cursor;
 import android.media.MediaScannerConnection;
@@ -76,7 +78,27 @@ public class AndroidStorage {
         }
         else {
             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT)
-                activity.getContentResolver().takePersistableUriPermission(uri, storageIntentPerms);
+            {
+                try {
+                    activity.getContentResolver().takePersistableUriPermission(uri, storageIntentPerms);
+                } catch (SecurityException e) {
+                    Log.w("Flycast", "takePersistableUriPermission failed", e);
+                    AlertDialog.Builder dlgAlert  = new AlertDialog.Builder(activity);
+                    dlgAlert.setMessage("Can't get permissions to access this folder.\nPlease select a different one.");
+                    dlgAlert.setTitle("Storage Error");
+                    dlgAlert.setPositiveButton("Ok",
+                            new DialogInterface.OnClickListener() {
+                                @Override
+                                public void onClick(DialogInterface dialog,int id) {
+                                    addStorageCallback(null);
+                                }
+                            });
+                    dlgAlert.setIcon(android.R.drawable.ic_dialog_alert);
+                    dlgAlert.setCancelable(false);
+                    dlgAlert.create().show();
+                    return;
+                }
+            }
             if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
                 String realPath = getRealPath(uri);
                 if (realPath != null) {

shell/android-studio/flycast/src/main/java/com/flycast/emulator/BaseGLActivity.java

@@ -270,7 +270,10 @@ public abstract class BaseGLActivity extends Activity implements ActivityCompat.
     }
     @Override
     public boolean onGenericMotionEvent(MotionEvent event) {
-        if ((event.getSource() & InputDevice.SOURCE_CLASS_JOYSTICK) == InputDevice.SOURCE_CLASS_JOYSTICK && event.getAction() == MotionEvent.ACTION_MOVE) {
+        if ((event.getSource() & InputDevice.SOURCE_CLASS_JOYSTICK) == InputDevice.SOURCE_CLASS_JOYSTICK
+                && event.getAction() == MotionEvent.ACTION_MOVE
+                && event.getDevice() != null)
+        {
             List<InputDevice.MotionRange> axes = event.getDevice().getMotionRanges();
             boolean rc = false;
             for (InputDevice.MotionRange range : axes)
@@ -416,9 +419,11 @@ public abstract class BaseGLActivity extends Activity implements ActivityCompat.
 
     }
 
-    private String getDefaultHomeDir()
-    {
-        return getExternalFilesDir(null).getAbsolutePath();
+    private String getDefaultHomeDir() {
+        File dir = getExternalFilesDir(null);
+        if (dir == null)
+            dir = getFilesDir();
+        return dir.getAbsolutePath();
     }
 
     private String checkHomeDirectory(String homeDir)

shell/android-studio/flycast/src/main/java/com/flycast/emulator/HomeMover.java

@@ -55,8 +55,13 @@ public class HomeMover {
             File f = getFile(parent);
             if (f != null)
                 return new File(f, kid).toURI().toString();
-            else
-                return storage.getSubPath(parent, kid);
+            else {
+                try {
+                    return storage.getSubPath(parent, kid);
+                } catch (RuntimeException e) {
+                    return null;
+                }
+            }
         }
 
         public FileInfo[] listContent(String folder)
@@ -97,6 +102,8 @@ public class HomeMover {
         }
 
         public boolean exists(String path) {
+            if (path == null)
+                return false;
             File file = getFile(path);
             if (file != null)
                 return file.exists();
@@ -139,6 +146,8 @@ public class HomeMover {
         Thread thread = new Thread(new Runnable() {
             private void copyFile(String path, String name, String toDir)
             {
+                if (path == null)
+                    return;
                 //Log.d("flycast", "Copying " + path + " to " + toDir);
                 try {
                     InputStream in = wrapper.openInputStream(path);

shell/android-studio/flycast/src/main/java/com/flycast/emulator/periph/InputDeviceManager.java

@@ -61,7 +61,7 @@ public final class InputDeviceManager implements InputManager.InputDeviceListene
     @Override
     public void onInputDeviceAdded(int i) {
         InputDevice device = InputDevice.getDevice(i);
-        if ((device.getSources() & InputDevice.SOURCE_CLASS_BUTTON) == InputDevice.SOURCE_CLASS_BUTTON) {
+        if (device != null && (device.getSources() & InputDevice.SOURCE_CLASS_BUTTON) == InputDevice.SOURCE_CLASS_BUTTON) {
             int port = 0;
             if ((device.getSources() & InputDevice.SOURCE_CLASS_JOYSTICK) == InputDevice.SOURCE_CLASS_JOYSTICK) {
                 port = this.maple_port == 3 ? 3 : this.maple_port++;