Which type of WindowManager LayoutParams should I use to show my view on top all my activities of my app?

Question

I don't want to show the overlay outside of the limits of my app, just above the activities of MY app. which type of WindowManager LayoutParams will achieve this? for API >= 25 and for API < 25?

This is what I use now and it doesn't work. for < 25 the overlay gets drawn even when the app is closed which I don't want to happen, and for >= 25 the overlay doesn't get drawn on other activities in my app.

windowParams = new WindowManager.LayoutParams(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT, WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH, PixelFormat.TRANSLUCENT);
windowParams.width = ViewGroup.LayoutParams.MATCH_PARENT;
windowParams.height = ViewGroup.LayoutParams.MATCH_PARENT;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
    windowParams.type = WindowManager.LayoutParams.TYPE_TOAST;
}
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N_MR1) {
    windowParams.type = WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY;
}