Question

I have a surfaceView setup and running, but when I resume it I get an error that the thread has already been started. What’s the proper way to handle when the app goes to the background and then back to the foreground? I’ve tinkered around and managed to get the app to come back without crashing… but the surfaceView doesn’t draw anything anymore. My code:

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
           Log.e("sys","surfaceCreated was called.");
           if(systemState==BACKGROUND){
                  thread.setRunning(true);

           }
           else {
        thread.setRunning(true);
               thread.start();
               Log.e("sys","started thread");
               systemState=READY;
           }



    }
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
           Log.e("sys","surfaceDestroyed was called.");
           thread.setRunning(false);
           systemState=BACKGROUND;
    }

Answer 1

The easy solution is to simply kill and restart the thread. Create methods resume() – creates thread object and starts it – and pause() – kills thread (see Lunarlander example) – in your SurfaceView class and call these from surfaceCreated and surfaceDestroyed to start and stop the thread.

Now in the Activity that runs the SurfaceView, you will also need to call the resume() and pause() methods in the SurfaceView from the Activity’s (or fragment’s) onResume() and onPause(). It’s not an elegant solution, but it will work.