Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference

Question

I have an error in logcat

java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference

Trying to view a picture in the list make a class for this code i think the error in the method View getView but i do not know where it is exactly i think may be here in the definition of thumbNail

public class useradaptor extends BaseAdapter {


             private Activity activity;
             private LayoutInflater inflater;
             private List<user> userItems;

ImageLoader imageLoader = AppController.getInstance().getImageLoader();

public useradaptor(Activity activity, List<user> userItems) {
    this.activity = activity;
    this.userItems = userItems;
}

@Override
public int getCount() {
    return userItems.size();
}

@Override
public Object getItem(int location) {
    return userItems.get(location);
}

@Override
public long getItemId(int position) {
    return position;
}

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

    user u = userItems.get(position);
    if (imageLoader == null)
        imageLoader = AppController.getInstance().getImageLoader();
    NetworkImageView thumbNail = (NetworkImageView) convertView.findViewById(R.id.imageview);
    thumbNail.setImageUrl(u.getPicture(), imageLoader);

    Cache cache = AppController.getInstance().getRequestQueue().getCache();
    Cache.Entry entry = cache.get(u.getPicture());
    if(entry != null){
        try {
            String data = new String(entry.data, "UTF-8");
            // handle data, like converting it to xml, json, bitmap etc.,
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
    }else{
        // cached response doesn't exists. Make a network call here
    }
    return convertView;
  }
}

score 1 · Answer 1 · answered Oct 29 '16 at 22:09

convertView will be null if there is no row for the ListView to offer you for recycling. When convertView is null, you need to create a list row, by one means or another. Typically, you use LayoutInflater, preferably the one that you get by calling getLayoutInflater() on an Activity.

Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference

1 Answers1