Android Activity 窗口大小縮放

WindowManager manager = getWindowManager();
		Display display = manager.getDefaultDisplay();
		android.view.WindowManager.LayoutParams params = getWindow().getAttributes();
		params.height = (int)(display.getHeight() * 0.5);
		params.width = (int)(display.getWidth() * 0.5);
		params.dimAmount = 0.0f;
		getWindow().setAttributes(params);
		getWindow().setGravity(Gravity.CENTER);