Android ListView Adapter returns NullPointerException

Question

The app crashes when trying to populate images in to a holder's ImageView or when I try to set an onclick listener to the holder imageview. It actually crashes if I try to do anything related to the holder's imageview.

The Image URL is not null, I checked

The ImageView exists, I checked

Adapter code (Important bits of it):

 public class FeedAdapter extends BaseAdapter {

    static private Activity activity;
    private static LayoutInflater inflater = null;
    ArrayList<ActivityTable> actList = new ArrayList<ActivityTable>();
    Holder holder;

    public FeedAdapter(Activity a, ArrayList<ActivityTable> actList) {
            activity = a;
            inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            this.actList = actList;
    }

    public View getView(int position, View convertView, ViewGroup parent) {

            View vi = convertView;
            final ActivityTable act = actList.get(position);

            if (vi == null) {
                  vi = inflater.inflate(R.layout.feed_single_picture, parent, false);
                  holder = new Holder();
                  holder.media = (ImageView) vi.findViewById(R.id.postphoto);
                  //can't set an image to it either. it crashes.
            }
            else {
                  holder = (Holder) vi.getTag();
            }

            //This is where it crashes
            holder.media.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {

                              //other on Click related Code

                        }
            });
       return vi;
    }

    public static class Holder {
            ImageView media;
    }
}

Why does the Holder's ImageView crash? I tried adding a TextView, ImageButton, etc and all of them work properly. Just this specific imageview crashes. What am I doing wrong?

EDIT: Crash Log

    FATAL EXCEPTION: main
    Process: com.metalproject.metalprojectmobile, PID: 5737
    java.lang.NullPointerException
            at Adapter.FeedAdapter.getView(FeedAdapter.java:456)
            at android.widget.AbsListView.obtainView(AbsListView.java:2689)
            at android.widget.ListView.makeAndAddView(ListView.java:1801)
            at android.widget.ListView.fillDown(ListView.java:697)
            at android.widget.ListView.fillGap(ListView.java:661)

The above line: 456 points to -> holder.media.setOnClickListener(new View.OnClickListener() {

Answer 1

you should modify your code as below :

if (vi == null) {
    vi = inflater.inflate(R.layout.feed_single_picture, parent, false);
    holder = new Holder();
    holder.media = (ImageView) vi.findViewById(R.id.postphoto);
}

and also remove them from outer code of if else

Answer 2

Fix will be like this:

public View getView(int position, View convertView, ViewGroup parent) {
    View vi = convertView;
    final ActivityTable act = actList.get(position);

    if (vi == null) {
        vi = inflater.inflate(R.layout.feed_single_picture, parent, false);
        holder = new Holder();
        vi.setTag(holder);
    }else {
        holder = (Holder) vi.getTag();
    }

    holder.media.setOnClickListener(new View.OnClickListener() {
       @Override
       public void onClick(View v) {
       }
    });
    return vi;
}

static class Holder {

    private ImageView media;

    Holder(View view){
        this.media = (ImageView) view.findViewById(R.id.postphoto);
    }

}