Question

Attempt to invoke virtual method 'android.os.Handler android.support.v4.app.FragmentHostCallback.getHandler()' on a null object reference
                                                              at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1588)
                                                              at android.support.v4.app.FragmentController.execPendingActions(FragmentController.java:330)
                                                              at android.support.v4.app.FragmentActivity.onResume(FragmentActivity.java:441)
                                                              at com.app.rare10.activities.ViewAllMemberActivity.onResume(ViewAllMemberActivity.java:192)
                                                              at com.app.rare10.activities.ViewAllMemberActivity$1.onReceive(ViewAllMemberActivity.java:74)
                                                              at android.support.v4.content.LocalBroadcastManager.executePendingBroadcasts(LocalBroadcastManager.java:297)
                                                              at android.support.v4.content.LocalBroadcastManager.access$000(LocalBroadcastManager.java:46)
                                                              at android.support.v4.content.LocalBroadcastManager$1.handleMessage(LocalBroadcastManager.java:116)
                                                              at android.os.Handler.dispatchMessage(Handler.java:102)
                                                              at android.os.Looper.loop(Looper.java:135)
                                                              at android.app.ActivityThread.main(ActivityThread.java:5254)
                                                              at java.lang.reflect.Method.invoke(Native Method)
                                                              at java.lang.reflect.Method.invoke(Method.java:372)
                                                              at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
                                                              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698

Answer 1

我使用布尔值来防止每当活动被销毁并且已经恢复。

boolean hasStop;
.
.
.
.
//here is when I need to prevent
if(!hasStop)
   //Statement
.
.
.
@Override
protected void onDestroy() {
    super.onDestroy();
    hasStop=true;
}

@Override
protected void onResume() { 
    super.onResume();
    hasStop=false;
}

Answer 2

我认为你应该实施 YourFragment.OnFragmentInteractionListener 在您的活动中，因为片段容器需要上下文和处理程序，上下文是您的活动，处理程序是接口，并且解决了这个问题。

Answer 3

如果与https://code.google.com/p/android/issues/detail?id=216157

相关

I work around this way:
@Override
  protected void onDestroy() {
        Log.d(TAG, "onDestroy");
          try {
            super.onDestroy();
        } catch (NullPointerException npe) {
            Log.e(TAG, "NPE: Bug workaround");
        }

Answer 4

检查您的覆盖方法是否具有正确的超级方法。我的意思是

 @Override
public void onPause() {
    super.onPause();

}

应该有super.onPause（）;只是没有其他方法。

Answer 5

以防任何未来的人有这个问题.... 如果您在onDestroy()中调用onStop()，则会抛出无法销毁活动错误

@Override
protected void onStop() {
    super.onStop();
    onDestroy(); //Don't call this!!!
}

所以请不要在onDestroy()

中呼叫onStop()

Answer 6

我有同样的问题。原因是我创建了PagerAdapter，它在保留的Fragment中保存了Context的链接。解决方案 - 重置适配器链接到片段视图重新创建后的上下文。

适配器类：

class TrackingDaysAdapter : PagerAdapter() {

var context: Context? = null

var trackingDays: List<TrackingDay> = emptyList()
    set(value) {
        field = value
        notifyDataSetChanged()
    }

    override fun instantiateItem(container: ViewGroup, position: Int): Any {
        val trackingDayViewImpl = TrackingDayViewImpl(context!!, trackingDays[position].date)
        container.addView(trackingDayViewImpl)
        return trackingDayViewImpl
    }

    override fun destroyItem(container: ViewGroup, position: Int, `object`: Any?) {
        container.removeView(`object` as View)
    }

    override fun isViewFromObject(view: View?, `object`: Any?) = view == `object`

    override fun getCount() = trackingDays.size
}

和片段类：

class TrackingsFragment : BackStackFragment<TrackingsView, TrackingsPresenter>(), TrackingsView {
@Inject lateinit var adapter: TrackingDaysAdapter

override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
    super.onViewCreated(view, savedInstanceState)

    adapter.context = context
}

}

Answer 7

Not a great solution. But You use this until google fixes
@Override
public void finishUpdate(ViewGroup container) {
    try{
        super.finishUpdate(container);
    } catch (NullPointerException nullPointerException){
        System.out.println(" NPE in FragmentPagerAdapter.finishUpdate");
    }
}

尝试在空对象上调用虚拟方法'android.os.Handler android.support.v4.app.FragmentHostCallback.getHandler（）'

7 个答案: