android - PreferenceFragment 中的上下文

Question

取自http://developer.android.com/guide/topics/ui/settings.html :

Note: A PreferenceFragment doesn't have a its own Context object. If you need a Context object, you can call getActivity(). However, be careful to call getActivity() only when the fragment is attached to an activity. When the fragment is not yet attached, or was detached during the end of its lifecycle, getActivity() will return null.

如果我从 PreferenceFragment 的 OnCreate() 方法中调用 getActivity() ，那么我是否可以确保该 fragment 附加到它的 Activity - 或者在这种情况下您是否应该通过其他方式获取上下文？

我需要上下文的原因是我正在尝试使用来自 PreferenceFragment 的 Toast 通知

Answer 1

如果您想确保上下文可用，您需要等到 fragment 已附加到 Activity 。对此的回调是 onAttach(Activity)方法。

根据 fragment 的生命周期状态，getActivity() 方法也可以返回 null。