Cannot resolve method getActivity()

问题

• I am new to Android and learning to create fragments in Android by following this
  example: Fragment Navigation Drawer

• The code between Navigating between Menu Items and Add Navigation Header consists a method getActivity().

• As the author didn't mentioned where to paste this code, I pasted in my MainActivity.java file

• Is code between Navigating between Menu Items and Add Navigation Header pasted at correct location by me?

• In method selectDrawerItem(MenuItem menuItem) there is a comment // Create a new fragment and specify the planet to show based on position
  Does author expects me to add something over here.

• The project files layout created by me on AndroidStudio is as follow:AndroidStudio Snapshot

回答1:

You can use:

this Or `MainActivity.this`

Instead of:

getActivity()

回答2:

An Activity has no getActivity() method.
Fragments have.

Because getActivity() says: "return the Activity which contains me".

And while Framents are contained in Activities, Activities themselves aren't.

回答3:

In Fragment it is best to use onAttach() method to get the instance of an Activity attached to it.

@Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
    }

来源：https://stackoverflow.com/questions/32527199/cannot-resolve-method-getactivity