获取 backstack 中的最新片段 [英] get the latest fragment in backstack

问题描述

如何获取添加到后台堆栈中的最新片段实例(如果我不知道片段标签和 ID)?

How can I get the latest fragment instance added in backstack (if I do not know the fragment tag & id)?

FragmentManager fragManager = activity.getSupportFragmentManager();
FragmentTransaction fragTransacion = fragMgr.beginTransaction();

/****After add , replace fragments 
  (some of the fragments are add to backstack , some are not)***/

//HERE, How can I get the latest added fragment from backstack ??

推荐答案

您可以使用 API 级别 14 中引入的 FragmentManager.BackStackEntry 的 getName() 方法. 此方法将返回一个标签，该标签是您使用 addTobackStack(tag) 将 Fragment 添加到后台堆栈时使用的标签.

You can use the getName() method of FragmentManager.BackStackEntry which was introduced in API level 14. This method will return a tag which was the one you used when you added the Fragment to the backstack with addTobackStack(tag).

int index = getActivity().getFragmentManager().getBackStackEntryCount() - 1
FragmentManager.BackStackEntry backEntry = getFragmentManager().getBackStackEntryAt(index);
String tag = backEntry.getName();
Fragment fragment = getFragmentManager().findFragmentByTag(tag);

您需要确保像这样将片段添加到后台堆栈:

You need to make sure that you added the fragment to the backstack like this:

fragmentTransaction.addToBackStack(tag);

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