Question

I’m quite new to Android programming but familiar with C/C++ and Linux enough to program a few stuff. In my next project, I’ve to run some native application (Linux applications) under Android.

The executable I’m calling is using the framebuffer device to produce screen output. When I try to just call the program the output of the program is lost because Android is redrawing the screen, thus overwriting the framebuffer.

In order to prevent this, I made a “stubbing” Android program, which actually has no window design (just a black screen) but calls my program. This is working good to some extend; however, whenever I rotate the screen, or some Tattoo notification comes, Android redraws the screen and we’re back to frame #1…

Thus, I wondered if there is a “low level” API or something, which can prevent Android from using the screen at all, as long as I release it. Shortly, like a WakeLock preventing phone from sleeping, I want a ‘Lock’ which will lock the screen (framebuffer device) completely. Does anyone know how can I achieve such functionality?

PS: This might have something to do with SurfaceFlinger, but I’ve read somewhere that it doesn’t publish any API to user-level.

Answer 1

The executable I’m calling is using the framebuffer device to produce screen output.

That’s not supported.

Thus, I wondered if there is a “low level” API or something, which can prevent Android from using the screen at all, as long as I release it.

Nothing that is supported at the SDK or NDK levels. You are welcome to create your own custom firmware that does whatever you want, and load that custom firmware on your own device.

Otherwise, please use a supported means for interacting with the screen (e.g., OpenGL natively in C/C++).