FragmentStatePagerAdapter与ChildFragmentManager - FragmentManagerImpl.getFragment导致NullPointerException异常 [英] FragmentStatePagerAdapter with ChildFragmentManager - FragmentManagerImpl.getFragment results in NullPointerException
问题描述
编辑2
我现在设法摆脱错误的使用从这里的伎俩<一href="https://$c$c.google.com/p/android/issues/detail?id=42601#c10">https://$c$c.google.com/p/android/issues/detail?id=42601#c10所以这就是reoson为什么我的最后一次编辑放在了我的问题之上。
I now managed to get rid of the error with using the trick from here https://code.google.com/p/android/issues/detail?id=42601#c10 so that's the reoson why my last edit is placed on top of my question.
但是，这导致了一个错误：
But this led to the next error:
java.lang.NullPointerException
at android.support.v4.app.FragmentManagerImpl.getFragment(FragmentManager.java:569)
at android.support.v4.app.FragmentStatePagerAdapter.restoreState(FragmentStatePagerAdapter.java:211)
at android.support.v4.view.ViewPager.onRestoreInstanceState(ViewPager.java:1281)
at android.view.View.dispatchRestoreInstanceState(View.java:12043)
at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2688)
at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2694)
at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2694)
at android.view.View.restoreHierarchyState(View.java:12021)
at android.support.v4.app.Fragment.restoreViewState(Fragment.java:425)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:949)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1460)
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4800)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:798)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:565)
at dalvik.system.NativeStart.main(Native Method)
现在我不知道在哪里继续...
And now I don't know where to continue...
修改0 - 第一个问题
我得到以下异常：
java.lang.IllegalStateException: No activity
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1091)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1086)
at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:1877)
at android.support.v4.app.Fragment.performActivityCreated(Fragment.java:1492)
at android.support.v4.app._HoloFragment.performActivityCreated(_HoloFragment.java:251)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:947)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1460)
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4800)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:798)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:565)
at dalvik.system.NativeStart.main(Native Method)
我不知道从哪里开始。我使用的是最新的支持库（V4，rev18）。
I have no idea where to start. I'm using the up to date support library (v4, rev18).
一切工作正常，直到我添加了一个片段其持有 ViewPager 与组合FragmentStatePagerAdapter 。
Everything works fine until I add a Fragment which holds a ViewPager in combination with FragmentStatePagerAdapter.
我使用的是支持库到处都是，我想从<一个解决方案href="https://$c$c.google.com/p/android/issues/detail?id=42601">https://$c$c.google.com/p/android/issues/detail?id=42601...
I'm using the support library everywhere, I tried the solutions from https://code.google.com/p/android/issues/detail?id=42601...
但没有奏效尚未...
But nothing worked yet...
我不知道从哪里开始，没有任何人有一个提示？
I don't know where to start, does anyone have a hint?
修改1：背景和code
1）在我MainActivity我使用下列内容：的
第三页有viewpager ...
The third page has the viewpager...
public void setPage(int pos, boolean addToBackStack)
{
Fragment nextFragment = null;
FragmentTransaction transaction = null;
switch (pos)
{
case 0:
if (mFragmentAllRoutines == null)
mFragmentAllRoutines = new RoutinesListFragment();
if (!mFragmentAllRoutines.isVisible())
nextFragment = mFragmentAllRoutines;
break;
case 1:
if (mFragmentRoutine == null)
mFragmentRoutine = new RoutineFragment();
if (!mFragmentRoutine.isVisible())
nextFragment = mFragmentRoutine;
break;
case 2:
if (mFragmentDay == null)
mFragmentDay = new RoutineDayFragment();
if (!mFragmentDay.isVisible())
nextFragment = mFragmentDay;
break;
default:
break;
}
if (nextFragment != null)
{
// Fragment prevFragment = getSupportFragmentManager().findFragmentById(R.id.fragment);
transaction = getSupportFragmentManager().beginTransaction();
// if (prevFragment != null)
// transaction.detach(prevFragment);
transaction.replace(R.id.fragment, nextFragment, nextFragment.getClass().getName());
// transaction.attach(nextFragment);
if (addToBackStack)
transaction.addToBackStack(null);
transaction.commit();
}
}
2）的第三个片段：
2) the third fragment:
这是一个简单的片段与ViewPager和FragmentStatePagerAdapter。该FragmentStatePagerAdapter获得的在 getChildFragmentManager（）作为FragmentManager。而地方似乎有问题。
It's a simple Fragment with a ViewPager and a FragmentStatePagerAdapter. The FragmentStatePagerAdapter get's the getChildFragmentManager() as FragmentManager. And somewhere there seems to be the problem.
推荐答案
我没有足够的信誉评论...所以我必须写一个答案......
I don't have enough reputation to comment ... so I have to write an answer ...
我需要看到更多的code，以便知道在哪里应用此......但我也有类似的情况，你没有...我解决了childFragment问题，以同样的方式，并得到了相同空指针异常，因为你。
I would need to see more code in order to know where to apply this ... but I had a similar situation as you did... I solved the childFragment issue the same way, and got the same null pointer exception, as you have.
我还是设法解决这个问题......我会尽力来形容我的解决方案，为您所提供我不能确定在何处应用了修复的code ......这真的是一个修复......这不是一个优雅的方式来解决这个问题！它也不过帮我，我也不需要恢复状态，一旦我离开导航视图上寻呼机，所以没有缺点的我。
I did manage to solve it... I'll try to describe my solution, as with the code you supplied I am unsure as to where to apply the "fix" ... It really is a fix ... it's not an elegant way to solve this! It did however helped me, and I don't need to restore states once I navigate away on the view Pager, so no downside for me.
我有多个片段，实现了code静态位和onDetach（上<一个href="https://$c$c.google.com/p/android/issues/detail?id=42601#c10">https://$c$c.google.com/p/android/issues/detail?id=42601#c10),每个片段有一个寻呼机和onCreateView附上扩展FragmentStatePagerAdapter的适配器。
I have multiple Fragments, that implement the static bit of code and the onDetach (on https://code.google.com/p/android/issues/detail?id=42601#c10), each fragment has a pager, and onCreateView I attach an adapter that extends FragmentStatePagerAdapter.
在这些适配器我已经覆盖了restoreState方法什么都不做。
on those adapters I have overridden the restoreState method to do nothing
@Override
public void restoreState(Parcelable arg0, ClassLoader arg1) {
//do nothing here! no call to super.restoreState(arg0, arg1);
}
再次，这是不是最好的方式......但它没有解决的我的问题。
祝您好运！
这篇关于FragmentStatePagerAdapter与ChildFragmentManager - FragmentManagerImpl.getFragment导致NullPointerException异常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IT屋！
