Android:如何处理onBackPressed嵌套片段 [英] Android: how to handle onBackPressed Nested fragment

问题描述

我正在参加一个具有以下结构的活动

I'm in an activity with the following structure

 Activity
   ContainerFragment with a view pager
       fragment 1 within viewPager
           View 1 inside fragment 1
           View 2 inside fragment 1

当显示activity加载fragment1.view1时，如果发生某些用户交互View 1 close and View 2 Open(将其视为2张卡，则其中一张被隐藏，另一张被显示).从back press的View 1用户应该回到View 1.这变得比我想象的更令人头疼.我能想到的最好的方法是override activity.onBackPressed()，检查containerFragment当前是否不是null并调用containerFragment.onBackPressed()(自定义方法)，然后检查fragment1不是null并调用然后检查view 2是否显示，如果是，则关闭View 2并显示view 1. android中有没有更简单的方法来解决这样的问题?我无法控制应用程序这一部分的结构.

When the activity loads fragment1.view1 is shown, if some user interaction happens View 1 close and View 2 Open (think of it as 2 cards, one gets hidden another gets shown). From View 1 on back press user should back to View 1 . This became more of a headache than I thought it would be. The best I can come up with is to override activity.onBackPressed(), check if containerFragment is currently not null and call containerFragment.onBackPressed() (custom method), which then checks if fragment1 is not null and calls fragment1.onBackPressed() which then checks if view 2 is showing and if yes , then close View 2 and show view 1. Is there any simpler way in android to solve a problem like this? I don't have control over restructuring this part of the app.

摘要:我在另一个包含两个views的fragment中有一个fragment，我想在backpressed上从view 2转到view 1

Summary: I have a fragment inside another fragment which contains 2 views, I want to on backpressed go from view 2 to view 1

推荐答案

我将实现一个名为FragmentViewController的东西，它可以在Fragment中显示正确的视图.真的很简单，例如

I'd implement something called FragmentViewControllerwhich would be responsible for display proper view in your Fragment. It's really simple, for example

class FragmentViewController{
      private boolean firstView = true;

      public boolean isFirstView() { return firstView }
      public void setFirstView() { firstView = true; }       
      public void setSecondView() { firstView = false; }
} 

根据状态 (FragmentViewController)在片段中显示视图.每次状态更改后，刷新Fragment以显示正确的视图.

Show view in your Fragment based on state of FragmentViewController. After each change of state refresh Fragment to show proper view.

当显示view2时，调用setSecondView(). 在活动中覆盖onBackPressed，并管理FragmentViewController的状态以处理后退按钮，例如:当view2显示时，调用setFirstView来还原Fragment中的第一个视图.

When view2 will be show, call setSecondView(). Override onBackPressed in your Activity, and manage the state of FragmentViewController to handle back button pressed eg.: when view2 is showing call setFirstView to restore first view in Fragment.

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