Android does not solve the overflow menu bar displays the icon and set android: showAsAction = "ifRoom" but not in the navigation bar problem

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1. Set android: showAsAction = "ifRoom" property but not in the navigation bar display problem.
   Increase namespace xmlns:app="http://schemas.android.com/apk/res-auto", while using app:showAsAction="ifRoom".
2. Set the icon property but does not display the icon problem.
   Use reflection to invoke a private method setOptionalIconsVisible, an icon will be displayed.

//setOptionalIconsVisible是私有的的，利用暴力反射可以调用
private void setOverflowIconVisible(int featureId, Menu menu) {
	//actionbar的featureId是8 ToolBar的是108
	if(featureId % 100 == Window.FEATURE_ACTION_BAR && menu != null) {
		if(menu.getClass().getSimpleName().equals("MenuBuilder")) {
			try {
				Method method = menu.getClass().getDeclaredMethod("setOptionalIconsVisible", Boolean.TYPE);
				method.setAccessible(true);
				method.invoke(menu, true);
			} catch(Exception e) {
			}
		}
	}
}