Creating a system overlay window (always on top)

Question

I\'m trying to create an always-op-top button/clickable-image which stays on top of all the windows all the time.

The proof of concept is

• here - Smar

Answer 1

I'm one of the developers of the Tooleap SDK. We also provide a way for developers to display always on top windows and buttons, and and we have dealt with a similar situation.

One problem the answers here haven't addressed is that of the Android "Secured Buttons".

Secured buttons have the filterTouchesWhenObscured property which means they can't be interacted with, if placed under a window, even if that window does not receive any touches. Quoting the Android documentation:

Specifies whether to filter touches when the view's window is obscured by another visible window. When set to true, the view will not receive touches whenever a toast, dialog or other window appears above the view's window. Refer to the {@link android.view.View} security documentation for more details.

An example of such a button is the install button when you try to install third party apks. Any app can display such a button if adding to the view layout the following line:

android:filterTouchesWhenObscured="true"

If you display an always-on-top window over a "Secured Button", so all the secured button parts that are covered by an overlay will not handle any touches, even if that overlay is not clickable. So if you are planing to display such a window, you should provide a way for the user to move it or dismiss it. And if a part of your overlay is transparent, take into account that your user might be confused why is a certain button in the underlying app is not working for him suddenly.