检测片段何时可​​见 [英] Detect when fragment becomes visible

问题描述

为什么不重复:建议的帖子仅适用于viewpager，或者在调用onResume时有效.

Why not a duplicate: Suggested post only works for a viewpager, or when onResume is called.

我有一个listfragment和一个detailfragment.单击列表项时，将打开详细信息片段.我通过隐藏listfragment完成此操作，并显示了detailfragment.当用户返回时，他返回到列表片段.

I have a listfragment and a detailfragment. The detail fragment is opened when a list item is clicked. I accomplish this by hiding the listfragment and I showing the detailfragment. When the user goes back, he returns to the listfragment.

如何检测用户何时返回我的片段，或何时可见我的片段?

How can I detect when the user gets back to my fragment, or when my fragment is visible?

请注意，我想继续使用.hide()和show()，并且我正在寻找一个监听器或onVisible来检查何时该片段成为可见，而不是检查是否可见的方法.

Please note that I would like to keep using .hide() and show() and that I am looking for a listener or a onVisible to check when the fragment becomes visible, and not a method to check if it is visible.

推荐答案

正如评论中指出的那样，setUserVisbileHint()不会自动调用，而是在ViewPager中使用时由FragmentPageAdapter调用.

As pointed out in the comments, setUserVisbileHint() does not get called automatically, but by the FragmentPageAdapter when used in a ViewPager.

对于问题中描述的场景，onHiddenChanged(boolean hidden) http://developer .android.com/reference/android/app/Fragment.html#onHiddenChanged(boolean)是合适的.
如文档中所述，每次Fragments隐藏状态更改时都会调用该方法，但在Fragment的初始设置时不会调用该方法.

For the scenario described in the question, onHiddenChanged(boolean hidden) http://developer.android.com/reference/android/app/Fragment.html#onHiddenChanged(boolean) is suitable.
As stated in the documentation, the method gets called every time the Fragments hidden state changes, but not on the initial setup of the Fragment.

您可以使用setUserVisibleHint() http://developer.android.com/reference/android/support/v4/app/Fragment.html#setUserVisibleHint(boolean)

如果isVisibleToUser设置为true，则应显示片段.

if isVisibleToUseris set to truethe fragment should be displayed.

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