问题描述
我有一个带有许多片段的导航抽屉，其中一个是带有两个 recyclerview 片段的 tablayout，RecyclerView 项目在导航抽屉片段之间切换后消失，我找到了一个解决方案，我需要使用 setOffscreenPageLimit() 方法ViewPager 但它给了我问题标题中提到的错误
i have a navigation drawer with a number of fragments and one of them is a tablayout with two recyclerview fragments , the RecyclerView items disappear after switching between navigation drawer fragments , i found a solution that i need to use method setOffscreenPageLimit() with the ViewPager but it gives me the bug that is mentioned in the question title
这是我的日志
java.lang.IllegalStateException: FragmentManager is already executing transactions
at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:1626)
at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:679)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:143)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1240)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1088)
at android.support.v4.view.ViewPager.setOffscreenPageLimit(ViewPager.java:852)
at com.amir.ahmed.EELUStudentUnion.SelectionFragment.setupViewPager(SelectionFragment.java:59)
at com.amir.ahmed.EELUStudentUnion.SelectionFragment.onActivityCreated(SelectionFragment.java:40)
at android.support.v4.app.Fragment.performActivityCreated(Fragment.java:2089)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1133)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1290)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:801)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1677)
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:536)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7225)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
那是选项卡布局片段代码
an that is the tab layout fragment code
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
viewPager = (ViewPager) getActivity().findViewById(R.id.viewpager);
setupViewPager(viewPager);
viewPager.setOffscreenPageLimit(2);
tabLayout = (TabLayout) getActivity().findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
setupTabIcons();
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getFragmentManager());
adapter.addFrag(new Courses(), "IT");
adapter.addFrag(new CoursesBussiness(), "Business");
viewPager.setAdapter(adapter);
}
推荐答案
我遇到了和你类似的问题，经过几个小时的研究，我发现了这个问题.如果您的 ViewPager 是在 Fragment 内部创建的，则需要对 FragmentPagerAdapter 使用 getChildFragmentManager()，而不是 getFragmentManager().
I encountered the similar issue as you, after several hours research, I found the issue. If your ViewPager is created inside the Fragment, you need to use getChildFragmentManager() for the FragmentPagerAdapter, rather than getFragmentManager().
所以你的 setupViewPager() 方法应该是这样的.
So your setupViewPager() method should look like this.
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getChildFragmentManager());
adapter.addFrag(new Courses(), "IT");
adapter.addFrag(new CoursesBussiness(), "Business");
viewPager.setAdapter(adapter);
}
问题的根本原因是您在 Fragment 中嵌入了 Fragments，这就是它会抛出异常的原因.
The root cause of the issue is you embeded Fragments inside the Fragment, that's why it will throw the exception.
java.lang.IllegalStateException: FragmentManager is already executing transactions
根据 Google 的文档:
According to the Google's docs:
您现在可以在片段中嵌入片段.这对于一个有用的您希望在其中放置动态和可重用的各种情况将 UI 组件转换为本身是动态的 UI 组件可重复使用的.例如，如果您使用 ViewPager 创建片段左右滑动并占用大部分屏幕空间，你现在可以将片段插入每个片段页面.嵌套一个片段，只需在您所在的 Fragment 上调用 getChildFragmentManager()想添加一个片段.这将返回一个 FragmentManager，您可以像平常一样从顶级活动中使用来创建分片交易.
You can now embed fragments inside fragments. This is useful for a variety of situations in which you want to place dynamic and re-usable UI components into a UI component that is itself dynamic and re-usable. For example, if you use ViewPager to create fragments that swipe left and right and consume a majority of the screen space, you can now insert fragments into each fragment page. To nest a fragment, simply call getChildFragmentManager() on the Fragment in which you want to add a fragment. This returns a FragmentManager that you can use like you normally do from the top-level activity to create fragment transactions.
这篇关于FragmentManager 在使用 setOffscreenPageLimit() 方法后已经在执行事务的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！