EditFriendsActivity won't open in Ribbit Application

When I run the ribbit application and try to open the EditFriendsActivity tab. I get this error code in my logcat:

07-22 06:06:35.649: E/AndroidRuntime(5503): FATAL EXCEPTION: main 07-22 06:06:35.649: E/AndroidRuntime(5503): java.lang.NullPointerException 07-22 06:06:35.649: E/AndroidRuntime(5503): at com.jordanpeterson.textly.adapters.UserAdapter.getView(UserAdapter.java:49) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.AbsListView.obtainView(AbsListView.java:2033) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.GridView.makeAndAddView(GridView.java:1323) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.GridView.makeRow(GridView.java:328) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.GridView.fillDown(GridView.java:281) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.GridView.fillFromTop(GridView.java:403) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.GridView.layoutChildren(GridView.java:1215) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.AbsListView.onLayout(AbsListView.java:1863) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.View.layout(View.java:11284) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.ViewGroup.layout(ViewGroup.java:4232) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.RelativeLayout.onLayout(RelativeLayout.java:925) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.View.layout(View.java:11284) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.ViewGroup.layout(ViewGroup.java:4232) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.FrameLayout.onLayout(FrameLayout.java:431) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.View.layout(View.java:11284) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.ViewGroup.layout(ViewGroup.java:4232) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1628) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1486) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.LinearLayout.onLayout(LinearLayout.java:1399) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.View.layout(View.java:11284) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.ViewGroup.layout(ViewGroup.java:4232) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.widget.FrameLayout.onLayout(FrameLayout.java:431) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.View.layout(View.java:11284) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.ViewGroup.layout(ViewGroup.java:4232) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1497) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2453) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.os.Handler.dispatchMessage(Handler.java:99) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.os.Looper.loop(Looper.java:137) 07-22 06:06:35.649: E/AndroidRuntime(5503): at android.app.ActivityThread.main(ActivityThread.java:4429) 07-22 06:06:35.649: E/AndroidRuntime(5503): at java.lang.reflect.Method.invokeNative(Native Method) 07-22 06:06:35.649: E/AndroidRuntime(5503): at java.lang.reflect.Method.invoke(Method.java:511) 07-22 06:06:35.649: E/AndroidRuntime(5503): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:3151) 07-22 06:06:35.649: E/AndroidRuntime(5503): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:2918) 07-22 06:06:35.649: E/AndroidRuntime(5503): at dalvik.system.NativeStart.main(Native Method)

Here is my UserAdapter code: import java.util.List; import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import android.widget.GridView; import android.widget.ImageView; import android.widget.TextView;

import com.jordanpeterson.textly.R; import com.jordanpeterson.textly.utils.MD5Util; import com.parse.ParseUser; import com.squareup.picasso.Picasso;

public class UserAdapter extends ArrayAdapter<ParseUser> {

protected Context mContext;
protected List<ParseUser> mUsers;

public UserAdapter(Context context, List<ParseUser> users) {
    super(context, R.layout.message_item, users);
    mContext = context;
    mUsers = users;
}

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

    if (convertView == null) {
        convertView = LayoutInflater.from(mContext).inflate(
                R.layout.user_item, null);
        holder = new ViewHolder();
        holder.userImageView = (ImageView) convertView
                .findViewById(R.id.userImageView);
        holder.nameLabel = (TextView) convertView.findViewById(R.id.nameLabel);
        holder.checkImageView = (ImageView) convertView
                .findViewById(R.id.checkImageView);
        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }

    ParseUser user = mUsers.get(position);
    String email = user.getEmail().toLowerCase();

    if (email.equals("")) {
        holder.userImageView.setImageResource(R.drawable.avatar_empty);
    } else {
        String hash = MD5Util.md5Hex(email);
        String gravatarUrl = "http://www.gravatar.com/avatar/" + hash
                + "?s=204&d=404";
        Picasso.with(mContext).load(gravatarUrl)
                .placeholder(R.drawable.avatar_empty)
                .into(holder.userImageView);
    }

    holder.nameLabel.setText(user.getUsername());

    GridView gridView = (GridView) parent;
    if (gridView.isItemChecked(position)) {
        holder.checkImageView.setVisibility(View.VISIBLE);
    } else {
        holder.checkImageView.setVisibility(View.INVISIBLE);
    }

    return convertView;
}

private static class ViewHolder {
    ImageView userImageView;
    ImageView checkImageView;
    TextView nameLabel;
}

public void refill(List<ParseUser> users) {
    mUsers.clear();
    mUsers.addAll(users);
    notifyDataSetChanged();
}

}