Question

我在一个活动的ViewPager中有4个片段。在其中一个片段中，我为结果启动了一个活动，并且在返回第一个活动时总是会崩溃。错误是：

Process: com.mycom.android.myapp.debug, PID: 13505
    java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=196610, result=0, data=Intent {  }} to activity {com.mycom.android.myapp.debug/com.mycom.android.myapp.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.app.Fragment.onActivityResult(int, int, android.content.Intent)' on a null object reference
            at android.app.ActivityThread.deliverResults(ActivityThread.java:3539)
            at android.app.ActivityThread.handleSendResult(ActivityThread.java:3582)
            at android.app.ActivityThread.access$1300(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1327)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            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:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.app.Fragment.onActivityResult(int, int, android.content.Intent)' on a null object reference
            at com.mycom.android.myapp.fragment.AgendaFragment.onActivityResult(AgendaFragment.java:415)

虽然我尝试评论片段的onActivityResult函数的主体，但仍然会发生。看起来片段没有及时恢复。

我该如何处理这件事？ TKS

更新：这是问题片段中的onActivityResult。有子片段，我确信这些片段中也有@Override。我尝试评论循环的主体，仍然没有运气。还有什么想法吗？感谢。

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    LOGD(TAG, "onActivityResult called BEFORE calling super");

    super.onActivityResult(requestCode, resultCode, data);
    LOGD(TAG, "onActivityResult called AFTER calling super");
    /**we need to broadcast this event to nested child fragments */
    List<Fragment> fragments = getChildFragmentManager().getFragments();
    if (!CollectionUtils.isEmpty(fragments)) {
        for (Fragment fragment : fragments) {
            if(fragment!=null){
                LOGD(TAG, "fragment not null");
                fragment.onActivityResult(requestCode, resultCode, data);

            }else
                LOGD(TAG,"fragment IS null");

        }
    }

}

更新2 ：因为我在一个嵌套的AgendaFragment片段中的startActivity（），跟随pvshnik在onActivityResult() not called in new nested fragment API的回答在ListFragment里面，这是一个AgendaFragment的子片段，我做了

getParentFragment().startActivityForResult(intent, requestCode);

Answer 1

您可以尝试这样：

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    List<Fragment> listOfFragments = getChildFragmentManager().getFragments();

    if(listOfFragments.size()>=1){
        for (Fragment fragment : listOfFragments) {
            if(fragment instanceof yourFragmentName){
                fragment.onActivityResult(requestCode, resultCode, data);
            }
        }
    }

    super.onActivityResult(requestCode, resultCode, data);
}

ViewPager片段中的onActivityResult崩溃

1 个答案: