android - getActivity().getFragmentManager() 与 fragment.getFragmentManager()

Question

我真的把这两种组合搞混了

getActivity().getFragmentManager()

和

fragment.getFragmentManager()

好像我们看到了 Activity.java 的内部实现

public FragmentManager getFragmentManager() {
        return mFragments.getFragmentManager();
    }

而 Fragment.java 有

 final public FragmentManager getFragmentManager() {
        return mFragmentManager;
    }

这是否意味着我们总是有不同的 FragmentManager 或其他？

Answer 1

fragment 是可以放置在 Activity 中的应用程序用户界面或行为的一部分。与 fragment 的交互是通过 FragmentManager 完成的，可以通过 Activity.getFragmentManager() 获得。 和 Fragment.getFragmentManager() .

getActivity().getFragmentManager()

Return the FragmentManager for interacting with fragments associated with this activity.

fragment.getFragmentManager()

Return the FragmentManager for interacting with fragments associated with this fragment's activity. Note that this will be non-null slightly before getActivity(), during the time from when the fragment is placed in a FragmentTransaction until it is committed and attached to its activity.

If this Fragment is a child of another Fragment, the FragmentManager returned here will be the parent's getChildFragmentManager().