Null Pointer Exception for the setText for getDayOfTheWeek when I Click on 7 Day

So, I'm running into a the following error, but only once the app is running and I click on the 7 Day button (which causes the app the crash):

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference at teamtreehouse.com.stormy.adapters.DayAdapter.getView(DayAdapter.java:63)

The line in DayAdapter it's referencing is: holder.dayLabel.setText(day.getDayOfTheWeek());

I've been bashing at this for a couple hours, reading the boards to see what people with similar issues are doing, but nothing is working. Any help would be greatly appreciated, I'm totally stuck. Here's my code:

package teamtreehouse.com.stormy.adapters;

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

import teamtreehouse.com.stormy.R; import teamtreehouse.com.stormy.weather.Day;

/**

• Created by Quintin on 6/24/2016. */ public class DayAdapter extends BaseAdapter {

  private Context mContext; private Day[] mDays;

  public DayAdapter(Context context, Day[] days) { mContext = context; mDays = days; }

  @Override public int getCount() { return mDays.length; }

  @Override public Object getItem(int position) { return mDays[position]; }

  @Override public long getItemId(int position) { return 0; //We aren't using this, but it can be used to tag items for easy reference }

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

  if (convertView == null) {
      //brand new
      convertView = LayoutInflater.from(mContext).inflate(R.layout.daily_list_item, null);
      holder = new ViewHolder();
      holder.iconImageView = (ImageView) convertView.findViewById(R.id.iconImageView);
      holder.temperatureLabel = (TextView) convertView.findViewById(R.id.temperatureLabel);
  
      convertView.setTag(holder);
  }
  else {
      holder = (ViewHolder) convertView.getTag();
  }
  
  Day day = mDays[position];
  
  holder.iconImageView.setImageResource(day.getIconId());
  holder.temperatureLabel.setText(day.getTemperatureMax() + "");
  holder.dayLabel.setText(day.getDayOfTheWeek());
  
  return convertView;
  

  } private static class ViewHolder { ImageView iconImageView; //public by default TextView temperatureLabel; TextView dayLabel; } }