ActionBar的Overflow按钮

好记不如烂文章

	/**
	 * ActionBar的Overflow按钮
	 */
	private void forceShowOverflowMenu() {
		try {
			ViewConfiguration config = ViewConfiguration.get(this);
			Field menuKeyField = ViewConfiguration.class
					.getDeclaredField("sHasPermanentMenuKey");
			if (menuKeyField != null) {
				menuKeyField.setAccessible(true);
				menuKeyField.setBoolean(config, false);
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}