Don't know what I'm doing wrong but nothing shows up in the Inbox list

package com.joinedit.ribbitpractice;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import com.parse.ParseObject;

import java.util.List;

/**
 * Created by yofu1 on 9/25/2015.
 */
public class MessageAdapter extends ArrayAdapter<ParseObject> {

    protected Context mContext;
    protected List<ParseObject> mMessages;

    //7.4 create custom layout for messages
    public MessageAdapter(Context context, List<ParseObject> messages) {
        super(context, R.layout.message_item);
        mContext = context;
        mMessages = messages;
    }


    //7.4 Override getView() in order to use a custom list adapter.
    // for  adapters for fragments, the adapter called a certain method to get an appropriate fragment.
    // And then it went ahead and adapted it and put it in the view.
    //This adapter, which is going to be attached to a list view,
    // is going to call a method, called getView,
    // and it's going to create the view, inflate it into a layout and then attach it into the list view.
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        //7.4 we want to do getView as efficiently as possible because the more efficient we are in this method, the faster it will perform
        ViewHolder holder;

        //RecyclerView (recycle views if it already exists.)
        if (convertView == null) { //if the view holder does not exist: create new holders
            convertView = LayoutInflater.from(mContext).inflate(R.layout.message_item, null);
            holder = new ViewHolder();
            holder.iconImageView = (ImageView) convertView.findViewById(R.id.messageIcon); //if you do (ImageView)findViewById(R.id.messageIcon) it will be RED error. need "convertView." in front
            //^  find view by ID is an activity method.
            //But we can call it from the convert view because in this  instance, we want to get it for the layout for this view.
            //Because we're not attached to the activity yet.

            //do the same thing for TextView holder:
            holder.nameLabel = (TextView) convertView.findViewById(R.id.senderLabel);
            convertView.setTag(holder);
        } else { // else if it already exits: reuse the old holders
            holder = (ViewHolder)convertView.getTag(); //.getTag() method gets the holder that was already created
        }

        //7.4 Now that we have the view, get the ParseObject that correspond to each item on the list:
        ParseObject message = mMessages.get(position); //get the positon of the message

        //7.4 change icon of the message in layout based on message type
        if (message.getString(ParseConstants.KEY_FILE_TYPE).equals(ParseConstants.TYPE_IMAGE)){ //if image file type ".equals" image then:

            holder.iconImageView.setImageResource(R.drawable.ic_action_picture); //set message Icon

        } else { //else set it to image icon for video:

            holder.iconImageView.setImageResource(R.drawable.ic_action_play_over_video);

        }
        holder.nameLabel.setText(message.getString(ParseConstants.KEY_SENDER_NAME)); //set message sender name



        return convertView;
    }

    //7.4 Create a ViewHolder class to use viewHolder (android convention)
    private static class ViewHolder {
        //7.4 a very simple class that just includes the data that is going to be displayed in the custom layout.
        ImageView iconImageView;
        TextView nameLabel;

    }
}