0

Some time ther is not error its run without error but most of time got error in this code, I try many thing for this. I try call this code on onStart() and I try this on onActivityCreted() too. but i get same error. This is my coding for show previous chat. I got error in limit().

final ListView listView = getListView();
    mChatListAdapter = new FirebaseListAdapter<>(mFirebaseRef.limit(50), Chat.class, R.layout.chat_item, R.layout.chat_item_other,
            R.layout.third_layout_chat, R.layout.fourth_layout_chat, getActivity(), chat_id);
    listView.setAdapter(mChatListAdapter);
    mChatListAdapter.registerDataSetObserver(new DataSetObserver() {
        @Override
        public void onChanged() {
            super.onChanged();
            listView.setSelection(mChatListAdapter.getCount() - 1);
        }
    });

This is error.

FATAL EXCEPTION: main Process: com.socialapp.android, PID: 8112 Theme: themes:{}                                                                   java.lang.RuntimeException: Unable to start activity ComponentInfo{com.socialapp.android/com.socialapp.chat.ChatViewActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'com.firebase.client.Query com.firebase.client.Firebase.limit(int)' on a null object reference
   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2450)
   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2520)
   at android.app.ActivityThread.-wrap11(ActivityThread.java)
   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1363)
   at android.os.Handler.dispatchMessage(Handler.java:102)
   at android.os.Looper.loop(Looper.java:148)
   at android.app.ActivityThread.main(ActivityThread.java:5466)
   at java.lang.reflect.Method.invoke(Native Method)
   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'com.firebase.client.Query com.firebase.client.Firebase.limit(int)' on a null object reference
   at com.socialapp.chat.ChatViewFragment.onStart(ChatViewFragment.java:609)
   at android.app.Fragment.performStart(Fragment.java:2244)
   at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1002)
   at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1148)
   at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1130)
   at android.app.FragmentManagerImpl.dispatchStart(FragmentManager.java:1958)
   at android.app.FragmentController.dispatchStart(FragmentController.java:163)
   at android.app.Activity.performStart(Activity.java:6274)
   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2413)
   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2520) 
   at android.app.ActivityThread.-wrap11(ActivityThread.java) 
   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1363) 
   at android.os.Handler.dispatchMessage(Handler.java:102) 
   at android.os.Looper.loop(Looper.java:148) 
   at android.app.ActivityThread.main(ActivityThread.java:5466) 
   at java.lang.reflect.Method.invoke(Native Method) 
   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Bhoomika Patel
  • 1
  • 1
  • Possible duplicate of [What is a NullPointerException, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) – Tim Jun 06 '16 at 09:33
  • This can be because `mFirebaseRef` variable is set to null at some point in time, due to reclaim of resources by android os. Try initializing this variable in `onStart()` or `onResume()`, since these are called every time app comes in to foreground from background. – Yogesh Jun 17 '16 at 08:47

0 Answers0