doubleclick exit app

	        if(_exitApp)
	        {
		        finish();
	        }
	        else
	        {
		        _exitApp = true;
		        showMessage( FPFContext.getInstance().getResourceManager().getString( R.string.click_to_exit ) );

		        final Handler handler = new Handler();
		        final Runnable r = new Runnable()
		        {
			        public void run()
			        {
				        _exitApp = false;
			        }
		        };
		        handler.postDelayed( r, 3000 );

	        }