问题
I'm using a ViewPager to display 4 different fragments. I use the action bar to display the tabs for the navigation. It looks like that:
My problem is that initially 3 of the tabs are fully visible and the last one is partially visible. Clicking on any of the first 3 tabs is ok but when I click on the last one, the app crashes:
09-06 13:35:01.825: E/AndroidRuntime(6676): FATAL EXCEPTION: main
09-06 13:35:01.825: E/AndroidRuntime(6676): java.lang.IllegalStateException: Content view not yet created
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.app.ListFragment.ensureList(ListFragment.java:328)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.app.ListFragment.getListView(ListFragment.java:222)
09-06 13:35:01.825: E/AndroidRuntime(6676): at com.szymontrapp.englishverbs.DictionaryListFragment.onLoadFinished(DictionaryListFragment.java:200)
09-06 13:35:01.825: E/AndroidRuntime(6676): at com.szymontrapp.englishverbs.DictionaryListFragment.onLoadFinished(DictionaryListFragment.java:1)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.app.LoaderManagerImpl$LoaderInfo.callOnLoadFinished(LoaderManager.java:427)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.app.LoaderManagerImpl.initLoader(LoaderManager.java:562)
09-06 13:35:01.825: E/AndroidRuntime(6676): at com.szymontrapp.englishverbs.DictionaryListFragment.onCreate(DictionaryListFragment.java:94)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.app.Fragment.performCreate(Fragment.java:1455)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:893)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.app.FragmentManagerImpl.performPendingDeferredStart(FragmentManager.java:823)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.app.Fragment.setUserVisibleHint(Fragment.java:819)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.app.FragmentPagerAdapter.setPrimaryItem(FragmentPagerAdapter.java:130)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.view.ViewPager.populate(ViewPager.java:1066)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:550)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:509)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:490)
09-06 13:35:01.825: E/AndroidRuntime(6676): at com.szymontrapp.englishverbs.DictionaryActivity$4.onTabSelected(DictionaryActivity.java:91)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.support.v7.app.ActionBarImplICS$TabWrapper.onTabSelected(ActionBarImplICS.java:454)
09-06 13:35:01.825: E/AndroidRuntime(6676): at com.android.internal.app.ActionBarImpl.selectTab(ActionBarImpl.java:587)
09-06 13:35:01.825: E/AndroidRuntime(6676): at com.android.internal.app.ActionBarImpl$TabImpl.select(ActionBarImpl.java:1084)
09-06 13:35:01.825: E/AndroidRuntime(6676): at com.android.internal.widget.ScrollingTabContainerView$TabClickListener.onClick(ScrollingTabContainerView.java:532)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.view.View.performClick(View.java:4211)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.view.View$PerformClick.run(View.java:17267)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.os.Handler.handleCallback(Handler.java:615)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.os.Handler.dispatchMessage(Handler.java:92)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.os.Looper.loop(Looper.java:137)
09-06 13:35:01.825: E/AndroidRuntime(6676): at android.app.ActivityThread.main(ActivityThread.java:4898)
09-06 13:35:01.825: E/AndroidRuntime(6676): at java.lang.reflect.Method.invokeNative(Native Method)
09-06 13:35:01.825: E/AndroidRuntime(6676): at java.lang.reflect.Method.invoke(Method.java:511)
09-06 13:35:01.825: E/AndroidRuntime(6676): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
09-06 13:35:01.825: E/AndroidRuntime(6676): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
09-06 13:35:01.825: E/AndroidRuntime(6676): at dalvik.system.NativeStart.main(Native Method)
It seems that somehow the last fragment is not loaded initially. I'm using a custom class extending FragmentPageAdapter and GetItem method is called only for the first 3.
Should I try to force load all 4 fragments initially? Alternatively, how to handle loading of the last fragment properly?
There's quite a lot of code around the view pager and those fragments, I'm not sure how much code will be needed to answer my question. Let me know if I need to post the full code here.
回答1:
Start the Loader in one of the callbacks(like onActivityCreated()) that run after the onCreateView() is called so you make sure that the Loader returning the data very fast doesn't put you in a position where the view of the Fragment is not yet created(the problem in your case).
来源：https://stackoverflow.com/questions/18649540/actionbar-with-viewpager-clicking-partially-visible-tab-crashes-the-app