Gridview onClickListerener nullpointer - android

The code: http://pastebin.com/5bhKULGd
the problem:
When you click an item in the gridview, OCLGenre (OnItemClickListener for Genre view)
fires an nullPointer at line 123. I'm trying to understand where the nullPointer comes from but can't find it.
The stack:
ERROR/AndroidRuntime(10511): FATAL EXCEPTION: main
java.lang.NullPointerException
at com.MMWeb.MMWeb$browse$1.onItemClick(MMWeb.java:123)
at android.widget.AdapterView.performItemClick(AdapterView.java:284)
at android.widget.AbsListView$PerformClick.run(AbsListView.java:1812)
at android.os.Handler.handleCallback(Handler.java:587)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:3683)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
at dalvik.system.NativeStart.main(Native Method)
Anyone got a pointer to where to find the source of this nullPointer?

If you try to access an object which is null. Like the below example.
ClassA objA;
At this time you have just declared this object but you have not initialized or instantiated it.
When you try to access any property or method in it, it will throw
NullPointerException.

Oke i found my problem By moving the ImageAdapter out of the "browse" class, the "browse" class did not have any reference to the ArrayList 'items'. I could find the problem because, after all, i defined the ArrayList at line 112. However, showGenres() uses a local ArrayList, and the ImageAdapter would put it in "browser.items". Fixed it by removing the local decleration of items on line 145, 154 and 162

Related

AsyncTask status is null

In my android app I am using AsyncTask. It was working perfectly but from last 2 days my app crashed when I called .execute() of AsyncTask. The error is:
FATAL EXCEPTION: main
java.lang.NullPointerException
at android.os.AsyncTask.execute(AsyncTask.java:378)
at com.riksof.a320.remote.RemoteObject.update(RemoteObject.java:117)
at com.fitmo.controller.activity.FitmoEditActivityDetailController.updateActivityDate(FitmoEditActivityDetailController.java:64)
at com.fitmo.controller.activity.FitmoEditActivityDetailController.access$0(FitmoEditActivityDetailController.java:51)
at com.fitmo.controller.activity.FitmoEditActivityDetailController$1.onClick(FitmoEditActivityDetailController.java:45)
at android.view.View.performClick(View.java:2532)
at android.view.View$PerformClick.run(View.java:9293)
at android.os.Handler.handleCallback(Handler.java:587)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:143)
at android.app.ActivityThread.main(ActivityThread.java:4263)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
at dalvik.system.NativeStart.main(Native Method)
When I saw the code inside AsyncTask.java, I found this code inside AsyncTask constructor:
switch (mStatus)
So I debug the AsyncTask status by calling getStatus() method of AsyncTask before calling execute() and the value is null here as well. What can be the reason for this any ideas ?
I am not getting this every time. Some times it works properly sometimes it doesn't.
Did you remove the AsyncTask myTask = new AsyncTask() by accident?

Crash ConcurrentModification

I have ocassional crash at my emulator, but for now never on tablet on which I am testing.
java.util.ConcurrentModificationException
at java.util.LinkedHashMap$LinkedHashIterator.nextEntry(LinkedHashMap.java:346)
at java.util.LinkedHashMap$EntryIterator.next(LinkedHashMap.java:375)
at java.util.LinkedHashMap$EntryIterator.next(LinkedHashMap.java:373)
at java.util.HashMap.writeObject(HashMap.java:1024)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1229)
at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1215)
at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1587)
at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1859)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1701)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1665)
at java.io.ObjectOutputStream.writeFieldValues(ObjectOutputStream.java:1153)
at java.io.ObjectOutputStream.defaultWriteObject(ObjectOutputStream.java:420)
at java.io.ObjectOutputStream.writeHierarchy(ObjectOutputStream.java:1251)
at java.io.ObjectOutputStream.writeNewObject(ObjectOutputStream.java:1587)
at java.io.ObjectOutputStream.writeObjectInternal(ObjectOutputStream.java:1859)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1701)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:1665)
at android.os.Parcel.writeSerializable(Parcel.java:1155)
at android.os.Parcel.writeValue(Parcel.java:1114)
at android.os.Parcel.writeMapInternal(Parcel.java:479)
at android.os.Bundle.writeToParcel(Bundle.java:1552)
at android.os.Parcel.writeBundle(Parcel.java:493)
at android.app.ActivityManagerProxy.activityPaused(ActivityManagerNative.java:1574)
at android.app.ActivityThread.handlePauseActivity(ActivityThread.java:3292)
at android.app.ActivityThread.access$2500(ActivityThread.java:125)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2040)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4627)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
at dalvik.system.NativeStart.main(Native Method)
It seems from the log it happens when the activity is going to pause.
All my activity are accessing a common super class static object (global data), which indeed has some linkedhashmap inside, and I am saving this globaldata with putSerializable inside onSaveInstanceState. I have tried to put save/restore of globaldata inside my base activity class inside sattic synchronized methods, but it didn't helped.
My I know from yours experiences if this is some internal android bug (maybe just emulator bug) or If I am managing saving of global data (which has LinkedHashMap inside) wrong. Or is there another way to share common data between activites?
Thanks

Android - crash occurs but the stack trace does not say where it happened

I have a null pointer exception somewhere, but I am not sure where. All I have is this error:
java.lang.NullPointerException
at android.widget.ArrayAdapter.getCount(ArrayAdapter.java:330)
at android.widget.AdapterView.checkFocus(AdapterView.java:700)
at android.widget.AdapterView$AdapterDataSetObserver.onInvalidated(AdapterView.java:823)
at android.widget.AbsListView$AdapterDataSetObserver.onInvalidated(AbsListView.java:5738)
at android.database.DataSetObservable.notifyInvalidated(DataSetObservable.java:47)
at android.widget.BaseAdapter.notifyDataSetInvalidated(BaseAdapter.java:59)
at android.widget.ArrayAdapter$ArrayFilter.publishResults(ArrayAdapter.java:513)
at android.widget.Filter$ResultsHandler.handleMessage(Filter.java:282)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4697)
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:787)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:554)
at dalvik.system.NativeStart.main(Native Method)
Would anyone have any ideas for how to debug this? I have not been able to reproduce it. It just sometimes happens and shows up in my crash logs.
Thanks!
Here's the code for ArrayAdapter: https://github.com/android/platform_frameworks_base/blob/master/core/java/android/widget/ArrayAdapter.java.
Assuming this is the right version, an NPE on line 330 would be caused if the adapter's dataset (i.e. the backing list or array) is null.
Hope that helps.

i keep getting java.lang.NullPointerException in my developer console error report, but i can't reproduce it in the emulator or on my phone

java.lang.NullPointerException
at com.surreall.yacht.yatzee.achievementsCheck`(yatzee.java:2031)`
at com.surreall.yacht.yatzee.gameOver(yatzee.java:1929)
at com.surreall.yacht.yatzee$4.onClick(yatzee.java:1250)
at android.view.View.performClick(View.java:2485)
at android.view.View$PerformClick.run(View.java:9080)
at android.os.Handler.handleCallback(Handler.java:587)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:130)
at android.app.ActivityThread.main(ActivityThread.java:3683)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:864)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:622)
at dalvik.system.NativeStart.main(Native Method)
obviously it is happening in the function achievementsCheck(), but no matter what i do i can't reproduce the null pointer exception. what does the "2031" mean in that line? can that tell me anything?
As per your question "what does the "2031" mean in that line?" It is the line number of the code on which the NullpointerException is generating. So look at that line it might be because of an object which is not initialized and has a null reference.
So for example if you have
Line 1: Object obj; //Note obj is not initialized here.
Line 2:
Line 3: //and you are trying to call
Line 4:
Line 5: obj.toString()///NullPointer will be generated here
You will see a NullPointerException generated at line 5
To solve this issue you will have to initialize obj correctly so in this case it will
Object obj = new Object();

Arrayadapter.getcount null point exception

I am getting the following stack trace (below is a complete copy) , this gives me little or no indication as to where in a massive application it is when going wrong and user feedback is nothing beyond "It crashed".
Is there anything I can do to pinpoint this more ?
java.lang.NullPointerException at android.widget.ArrayAdapter.getCount(ArrayAdapter.java:291)
at android.widget.AdapterView.checkFocus(AdapterView.java:689)
at android.widget.AdapterView$AdapterDataSetObserver.onInvalidated(AdapterView.java:813)
at android.database.DataSetObservable.notifyInvalidated(DataSetObservable.java:43)
at android.widget.BaseAdapter.notifyDataSetInvalidated(BaseAdapter.java:54)
at android.widget.ArrayAdapter$ArrayFilter.publishResults(ArrayAdapter.java:469)
at android.widget.Filter$ResultsHandler.handleMessage(Filter.java:282)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:143)
at android.app.ActivityThread.main(ActivityThread.java:4701)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
at dalvik.system.NativeStart.main(Native Method)
Look at the code for ArrayAdapter.getCount():
/**
* {#inheritDoc}
*/
public int getCount() {
return mObjects.size();
}
Clearly mObjects is null, i.e. your ListView or other AdapterView-derived type is trying to use the adapter before you've initialized it with it's data.
What you could do is putting debug information before every call to getCount() using the Log class
Log.d("tag", "Trying to get count on line 50 class Test");
then open logcat and find the last entry of this log before the error occures. Then you have the right location of the crash.

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