由于LayoutManager为NULL,RecycleView在Fragment中崩溃

我有三个标签,所有在一个tablayout,在Tab1,有一个RecycleView.

今天我想向它添加SwipeRefreshLayout:

在Tab1Fragment中:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.activity_main_list, container, false);
    recyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);
    staggeredGridLayoutManager = new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);
    recyclerView.setLayoutManager(staggeredGridLayoutManager); 
    swipeRefreshLayout = (SwipeRefreshLayout) view.findViewById(R.id.swiperefreshlayout);
    swipeRefreshLayout.setColorSchemeResources(android.R.color.holo_blue_bright, android.R.color.holo_green_light,
            android.R.color.holo_orange_light, android.R.color.holo_red_light);
    return view;
}

不幸的是,当我从tab1滚动到tab2,然后回到tab1时,活动崩溃:

java.lang.NullPointerException: Attempt to invoke virtual method 'boolean  
android.support.v7.widget.RecyclerView$LayoutManager.canScrollVertically()' on a null object reference
  at android.support.v7.widget.RecyclerView.computeVerticalScrollOffset(RecyclerView.java:1613)
  at android.view.View.canScrollVertically(View.java:12880)

但显然我已经设置了LayoutManger!似乎交错的网格布局已经消失了......

更多Weired是,当我只是单击tab1,tab2时,Activity不会崩溃,但是当我从tab2滚动到tab1时,它崩溃了

发生了什么？谢谢!

加上整个错误日志:

12-02 16:57:59.857 28189-28189/xyz.doutu.doutu E/AndroidRuntime: Process: xyz.doutu.doutu, PID: 28189
        ava.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.support.v7.widget.RecyclerView$LayoutManager.canScrollVertically()' on a null object reference
  at android.support.v7.widget.RecyclerView.computeVerticalScrollOffset(RecyclerView.java:1613)
  at android.view.View.canScrollVertically(View.java:12880)
  at android.support.v4.view.ViewCompatICS.canScrollVertically(ViewCompatICS.java:35)
  at android.support.v4.view.ViewCompat$ICSViewCompatImpl.canScrollVertically(ViewCompat.java:1253)
  at android.support.v4.view.ViewCompat.canScrollVertically(ViewCompat.java:1695)
  at android.support.v4.widget.SwipeRefreshLayout.canChildScrollUp(SwipeRefreshLayout.java:646)
  at android.support.v4.widget.SwipeRefreshLayout.onInterceptTouchEvent(SwipeRefreshLayout.java:660)
  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1961)
  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2408)
  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2050)
  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2408)
  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2050)
  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2408)
  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2050)
  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2408)
  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2050)
  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2408)
  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2050)
  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2408)
  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2050)
  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2408)
  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2050)
  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2408)
  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2050)
  at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:2390)
  at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1734)
  at android.app.Activity.dispatchTouchEvent(Activity.java:2833)
  at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:60)
  at android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:60)
  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:2351)
  at android.view.View.dispatchPointerEvent(View.java:8700)

小智.. 7

将您的recyclerView作业移至onViewCreated()而不是onCreateView().问题是当你TabFragment在viewPager滚动上分离并重新附加时.

将您的recyclerView作业移至onViewCreated()而不是onCreateView().问题是当你TabFragment在viewPager滚动上分离并重新附加时.