NullPointerException not found using ListActivity and ArrayAdapter

Question

Hi there stackoverflow , Now I ran into another problem ,I am working on a ListActivity from a custom ArrayAdapter so I can fully customize my Listview to include TextViews , switches , checkboxes .... I got a NullPointerException without I know from where its originating ! Here is my current code :

public class MenuActivity extends SherlockListActivity {
    ListView scroll;
    int time;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);


        try {
            scroll = this.getListView();



            this.setListAdapter(new MyAdapter(this.getApplicationContext()));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            finish();
        }




    }




    public View find(int x){

        return findViewById(x);

    }


    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        // TODO Auto-generated method stub


        super.onListItemClick(l, v, position, id);



        switch (position){
        case (0):{
            Toast.makeText(getApplicationContext(), "Hello you just chose \"Splash\"", Toast.LENGTH_SHORT).show();
        }break;
        case (1):{
            Toast.makeText(getApplicationContext(), "Its another one here !", Toast.LENGTH_SHORT).show();
        }break;
        case (2):{
            Toast.makeText(getApplicationContext(), String.valueOf(id) +" and "+ position, Toast.LENGTH_SHORT).show();

        }break;
        }


    }

    public void showToast(String toast){
        Toast.makeText(getApplicationContext(), toast, Toast.LENGTH_SHORT).show();
    }



}

class MyAdapter extends ArrayAdapter<String>{


    LayoutInflater inf = LayoutInflater.from(this.getContext());

    public MyAdapter(Context context) {
        super(context , 0 ,stringArray);
        inf.from(context);
        // TODO Auto-generated constructor stub
    }


    public static String[] stringArray= new String[]{"Splash"   , "Another Example" , "Future Checkable"};


    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub

        if (convertView == null){
            inf.inflate(R.layout.normal_row, parent , false);
        }
        switch(position){
        case(0):
            convertView = (LinearLayout) inf.inflate(R.layout.row_switch, parent,false);

            break;
        }


        return convertView;
    }




}

And My StackTrace :

12-09 17:52:55.631: E/AndroidRuntime(11921): FATAL EXCEPTION: main
12-09 17:52:55.631: E/AndroidRuntime(11921): java.lang.NullPointerException
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.widget.AbsListView.obtainView(AbsListView.java:2161)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.widget.ListView.makeAndAddView(ListView.java:1831)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.widget.ListView.fillDown(ListView.java:674)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.widget.ListView.fillFromTop(ListView.java:735)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.widget.ListView.layoutChildren(ListView.java:1652)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.widget.AbsListView.onLayout(AbsListView.java:1994)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.View.layout(View.java:14003)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.ViewGroup.layout(ViewGroup.java:4375)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.View.layout(View.java:14003)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.ViewGroup.layout(ViewGroup.java:4375)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1663)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1521)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.View.layout(View.java:14003)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.ViewGroup.layout(ViewGroup.java:4375)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.View.layout(View.java:14003)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.ViewGroup.layout(ViewGroup.java:4375)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1892)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1711)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.Choreographer.doCallbacks(Choreographer.java:562)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.Choreographer.doFrame(Choreographer.java:532)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.os.Handler.handleCallback(Handler.java:725)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.os.Handler.dispatchMessage(Handler.java:92)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.os.Looper.loop(Looper.java:137)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at android.app.ActivityThread.main(ActivityThread.java:5039)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at java.lang.reflect.Method.invokeNative(Native Method)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at java.lang.reflect.Method.invoke(Method.java:511)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
12-09 17:52:55.631: E/AndroidRuntime(11921):    at dalvik.system.NativeStart.main(Native Method)

score 4 · Accepted Answer · answered Dec 09 '12 at 16:13

4

Change this:

if (convertView == null){
     inf.inflate(R.layout.normal_row, parent , false);
}

to:

if (convertView == null){
     convertView = inf.inflate(R.layout.normal_row, parent , false);
}

Also, regarding having two types of rows in the ListView you should look at implementing the getViewTypeCount() and getItemViewType() methods of the adapter(as your current code will not work that well).

answered Dec 09 '12 at 16:13

user

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thanks , solved my problem ! but I didn't understand the second part where I have to implement these two , may you please give me an example ? – Dec 09 '12 at 19:30
@Seaskyways In order for your `ListView` to handle the two types of row ok you need to implement those two methods. I don't know any tutorial about this so I'm putting a link to one of my answer related to those methods http://stackoverflow.com/questions/9664100/different-row-layouts-in-listview/9665523#9665523 – user Dec 09 '12 at 19:48

NullPointerException not found using ListActivity and ArrayAdapter

1 Answers1