从Fragment设置适配器时，CustomListAdapter中的NullPointerException

Question

I have a ListView inside a LinearLayout named listView1 , and for a particular row, I have a LinearLayout inside which there is a com.facebook.widget.ProfilePictureViewer and a TextView. I have created a CustomListAdapter to populate the List. I am setting the adapter from the Request.executeMyFriendsRequestAsync().

I am posting this after researching in a number of similar post on the stackoverflow as well as other tutorials. Please help, I am stuck on this from last 1 day.

list_item.xml

<com.facebook.widget.ProfilePictureView
    android:padding="2dp"
    android:id="@+id/friendProfilePicture"
    android:layout_width="43dp"
    android:layout_height="44dp" >
</com.facebook.widget.ProfilePictureView>
<TextView
    android:id="@+id/tv_friendName"
    android:layout_height="wrap_content"
    android:layout_width="wrap_content"
    android:layout_gravity="center_vertical"
    android:paddingLeft="2dp"
    android:text="Name"/>

I think I am either setting the adapter wrong or have something mismatch in the adapter's constructor.

MyAdapter.java

public class MyAdapter extends ArrayAdapter<String> {

private final Context context;
private String[] names;
private String[] ids;

public MyAdapter(Context context, int layoutResourceId, String[] n, String[]i) {
    super(context, R.layout.list_item, n);
    this.context = context;
    names = n;
    ids = i;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View vi = inflater.inflate(R.layout.list_item, parent, false);
    TextView tvName = (TextView) vi.findViewById(R.id.tv_friendName);
    ProfilePictureView profilePic = (ProfilePictureView) vi.findViewById(R.id.profilepic);
    tvName.setText(names[position]);
    profilePic.setProfileId(ids[position]);
    return vi;
}
}

and here is the code where I am setting the adapter,

public class MainFragment extends Fragment {

and the statement for setting the adapter

context = MainActivity.context;

listView.setAdapter(new MyAdapter(context,R.layout.list_item, names, id));

There is a static variable context of type Context in the MainActivty.java,

names and id are two String Arrays which are having values and are not null.

Here is the StackTrace

07-15 07:02:07.729: E/AndroidRuntime(3367): FATAL EXCEPTION: main
07-15 07:02:07.729: E/AndroidRuntime(3367): java.lang.NullPointerException
07-15 07:02:07.729: E/AndroidRuntime(3367):     at android.widget.ArrayAdapter.init(ArrayAdapter.java:310)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at android.widget.ArrayAdapter.<init>(ArrayAdapter.java:128)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at azeem.anas.facebookloginbutton.MyAdapter.<init>(MyAdapter.java:19)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at azeem.anas.facebookloginbutton.MainFragment$3.onCompleted(MainFragment.java:103)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at com.facebook.Request$2.onCompleted(Request.java:285)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at com.facebook.Request$4.run(Request.java:1240)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at android.os.Handler.handleCallback(Handler.java:725)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at android.os.Handler.dispatchMessage(Handler.java:92)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at android.os.Looper.loop(Looper.java:137)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at android.app.ActivityThread.main(ActivityThread.java:5041)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at java.lang.reflect.Method.invokeNative(Native Method)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at java.lang.reflect.Method.invoke(Method.java:511)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-15 07:02:07.729: E/AndroidRuntime(3367):     at dalvik.system.NativeStart.main(Native Method)

Any help would greatly appreciated.

Answer 1

A very silly mistake i have done, in the following statement in the Adapter class

ProfilePictureView profilePic = (ProfilePictureView) vi.findViewById(R.id.profilepic); ,

I was referring to a wrong resource. It was actually

ProfilePictureView profilePic = (ProfilePictureView) vi.findViewById(R.id.friendProfilePicture);

---

Thanks to all those who made efforts in solving my problem

Answer 2

public class MyAdapter extends ArrayAdapter<String> {
   private String[] ids;

   public MyAdapter(Context context, int layoutResourceId, String[] n, String[] i) {
       super(context, R.layout.list_item, n);
       this.ids = i;
   }

   @Override
   public View getView(int position, View convertView, ViewGroup parent) {
      View view = convertView;
      if (view == null) {
         LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
         view = inflater.inflate(layoutResourceId, null);
      }
      TextView tvName = (TextView) view.findViewById(R.id.tv_friendName);
      ProfilePictureView profilePic = (ProfilePictureView) view.findViewById(R.id.profilepic);
      tvName.setText(getItem(position));
      profilePic.setProfileId(ids[position]);
      return view;
   }
}

Try this it should Work. And keep context = getActivity();

Important : call listView.setAdapter(new MyAdapter(context,R.layout.list_item, names, id)); in onActivityCreateed()