问题
When the user clicks on the Menu button I present a few menu items. One of them is a Sign Out button. I want to be able to change the text between "Sign In" and "Sign Out" depending on a boolean value I am tracking. How can I programmatically change the text in the menu?
回答1:
You want to override the onPrepareOptionsMenu function in the Activity. There is a menu parameter passed, you can simply find the menuitem that you want to show/hide (or change the image and text) and return true.
onPrepareOptionsMenu
回答2:
Override/Implement the onPrepareOptionsMenu(...) callback. Change what you add based on your sign-in state.
Alternatively, I haven't tested this but in my mind it works: When you create your menu items, keep a handle to the Sign In/Sign Out item in a class variable, and just update it by calling setTitle(...) as needed.
来源：https://stackoverflow.com/questions/5876109/how-to-programatically-change-an-item-in-the-options-menu