DisplayActivity.java

    /**
     * Sets full screen mode on the device, by setting parameters in the current
     * window and View
     * @param fullscreen
     */
    public void setFullScreen(boolean fullscreen) {
        // If full screen is set, sets the fullscreen flag in the Window manager
        getWindow().setFlags(
                fullscreen ? WindowManager.LayoutParams.FLAG_FULLSCREEN : 0,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        
        // Sets the global fullscreen flag to the current setting
        mFullScreen = fullscreen;

        // If the platform version is Android 3.0 (Honeycomb) or above
        if (Build.VERSION.SDK_INT >= 11) {
            
            // Sets the View to be "low profile". Status and navigation bar icons will be dimmed
            int flag = fullscreen ? View.SYSTEM_UI_FLAG_LOW_PROFILE : 0;
            
            // If the platform version is Android 4.0 (ICS) or above
            if (Build.VERSION.SDK_INT >= 14 && fullscreen) {
                
                // Hides all of the navigation icons
                flag |= View.SYSTEM_UI_FLAG_HIDE_NAVIGATION;
            }
            
            // Applies the settings to the screen View
            mMainView.setSystemUiVisibility(flag);

            // If the user requests a full-screen view, hides the Action Bar.
            if ( fullscreen ) {
                this.getActionBar().hide();
            } else {
                this.getActionBar().show();
            }
        }
    }