Android Facebook lock screen notification

Actually, ferdy182 was/is onto something.

Here's what I got using the android.permission.SYSTEM_ALERT_WINDOW:

So, I couldn't do this with an Activity. It just wouldn't work. I had to implement a Service which added a View using the WindowManager.

One possible workflow would be: a broadcast is received by your BroadcastReceiver => it starts a Service => the Service adds the required view.

Now, the code (the comments explain a few things):

public class MyService extends Service {    View mView;    @Override    public IBinder onBind(Intent intent) {        return null;    }    @Override    public void onCreate() {        super.onCreate();        // instance of WindowManager        WindowManager mWindowManager = (WindowManager) getSystemService(WINDOW_SERVICE);        LayoutInflater mInflater = (LayoutInflater)                                       getSystemService(Context.LAYOUT_INFLATER_SERVICE);        // inflate required layout file        mView = mInflater.inflate(R.layout.abc, null);        // attach OnClickListener        mView.findViewById(R.id.some_id).setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                // you can fire an Intent accordingly - to deal with the click event                // stop the service - this also removes `mView` from the window                // because onDestroy() is called - that's where we remove `mView`                stopSelf();            }        });        // the LayoutParams for `mView`        // main attraction here is `TYPE_SYSTEM_ERROR`        // as you noted above, `TYPE_SYSTEM_ALERT` does not work on the lockscreen        // `TYPE_SYSTEM_OVERLAY` works very well but is focusable - no click events        // `TYPE_SYSTEM_ERROR` supports all these requirements        WindowManager.LayoutParams mLayoutParams = new WindowManager.LayoutParams(            ViewGroup.LayoutParams.WRAP_CONTENT,             ViewGroup.LayoutParams.WRAP_CONTENT, 0, 0,            WindowManager.LayoutParams.TYPE_SYSTEM_ERROR,            WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED                    | WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD                    | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON                    | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON,                       PixelFormat.RGBA_8888);        // finally, add the view to window        mWindowManager.addView(mView, mLayoutParams);    }    @Override    public void onDestroy() {        super.onDestroy();        // remove `mView` from the window        removeViewFromWindow();    }    // Removes `mView` from the window    public void removeNow() {        if (mView != null) {            WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);            wm.removeView(mView);        }    }}

And finally, add the permission to your app's manifest:

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />

I think it is probably using the same trick as the Chat heads bubbles for Messenger.

Basically you use this permission"android.permission.SYSTEM_ALERT_WINDOW"to display your views above other apps.

I haven't tried myself but I am pretty sure they used this.

From the docs "Allows an application to open windows using the type TYPE_SYSTEM_ALERT, shown on top of all other applications. "http://developer.android.com/reference/android/Manifest.permission.html#SYSTEM_ALERT_WINDOW