Unable to call notifyDataSetChanged on CustomListAdapter

Question

I'm unable to refresh my CustomListAdapter object which extends ArrayAdapter, the method notifyDataSetChanged() is not available on it. I can call this within the object itself though.

Knowing this, I have created a method in the custom adapter class like so:

public void refreshAdapter(){
    notifyDataSetChanged();
}

but I'm unable to call this method in the activity where I create the adapter object so I'm back to square one. Why am I unable to call this method and notifyDataSetChanged()?

Here is my Adapter as requested:

import android.content.Context;
import android.content.SharedPreferences;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.TextView;

import com.henleyb.aeropressbrewer.R;
import com.henleyb.aeropressbrewer.model.CoffeeClass;

public class RecipeDetailsListAdapter extends ArrayAdapter {

    public SharedPreferences sharedPrefs;

    private TextView greenBox;
    private TextView peachBox;
    private String grindSize = "non set";
    private String tempType;

    public RecipeDetailsListAdapter(Context context, String[] values) {
        super(context, R.layout.d_brew_coffee_list_item, values);

        sharedPrefs = context.getSharedPreferences("com.henleyb.aeropressbrewer", 0);

    }

    public void refreshAdapter(){
        notifyDataSetChanged();
    }

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

        LayoutInflater theInflater = LayoutInflater.from(getContext());

        View theView = theInflater.inflate(R.layout.d_brew_coffee_list_item, parent, false);

        // text for the list items (changes to populate everything)
        greenBox = (TextView) theView.findViewById(R.id.tvGreenText);
        peachBox = (TextView) theView.findViewById(R.id.tvPeachText);

        // Depending on the position of the list, we change the row data to suit
        switch (position) {
            case 0:
                getGrams();
                break;
            case 1:
                getTemp();
                Log.i("HEN","We're in getTemp switch");
                break;
            case 2:
                getGrindSize();
                break;
            case 3:
                getInverted();
                break;
            default:
                Log.i("HEN", "INVALID SWITCH POS");

        }
        notifyDataSetChanged();

        return theView;
    }

    private void getGrams() {
        Log.v("HEN", "position = 0");


        greenBox.setText("Grams");
        peachBox.setText(Integer.toString(CoffeeClass.getCurrentSelectedCoffeeObject().getRecipeDetailsGrams()));

    }

    private void getTemp() {


        Log.i("HEN","We're in getTemp method!");
        greenBox.setText("Temp");

        tempType = sharedPrefs.getString("TEMPTYPE", "fahrenheit");

        switch (tempType) {
            case "celsius":
                Log.i("HEN","tempType now celsius");
                peachBox.setText(String.valueOf((int) CoffeeClass.getCurrentSelectedCoffeeObject().getRecipeDetailsTemp()) + "\u00b0C");
                break;

            case "fahrenheit":
                peachBox.setText(String.valueOf((int) CoffeeClass.getCurrentSelectedCoffeeObject().getRecipeDetailsTemp()) + "\u00b0f");
                break;
            default:
                peachBox.setText(String.valueOf((int) CoffeeClass.getCurrentSelectedCoffeeObject().getRecipeDetailsTemp()) + "!");
        }
    }

    private void getGrindSize() {
        Log.v("HEN", "position = 1");
        greenBox.setText("Grind Size");
        peachBox.setText(convertGrindSize());

    }

    private void getInverted() {
        Log.v("HEN", "position = 3");
        greenBox.setText("Inverted?");

        if (CoffeeClass.getCurrentSelectedCoffeeObject().getBrewID() == 1) {
            if (CoffeeClass.getCurrentSelectedCoffeeObject().getRecipeInverted()) {
                peachBox.setText("YES");
            } else {
                peachBox.setText("NO");
            }
        } else {
            peachBox.setText("NA");
        }
    }

    private String convertGrindSize() {
        Integer gs = CoffeeClass.getCurrentSelectedCoffeeObject().getRecipeDetailsGrindSize();

        if (gs >= 0 && gs <= 20) {
            grindSize = "Turkish";
        } else if (gs > 20 && gs <= 30) {
            grindSize = "Very \nFine";
        } else if (gs > 30 && gs <= 40) {
            grindSize = "Fine";
        } else if (gs > 40 && gs <= 50) {
            grindSize = "Medium \nFine";
        } else if (gs > 50 && gs <= 60) {
            grindSize = "Medium";
        } else if (gs > 60 && gs <= 70) {
            grindSize = "Medium \nCoarse";
        } else if (gs > 70 && gs <= 80) {
            grindSize = "Coarse";
        } else if (gs > 80 && gs <= 90) {
            grindSize = "Very \nCoarse";
        } else if (gs > 90 && gs <= 100) {
            grindSize = "Like Huge \nBoulders";
        }

        return grindSize;
    }


}

Answer 1

1. You DON'T need the:

   public void refreshAdapter() {
   
       notifyDataSetChanged();
   }
   

notifyDataSetChanged is a public method and it is available.

2. You are never referencing the String[] values,(by using getItem(position)) which is the whole point of ArrayAdapter and notifyDataSetChanged(). notifyDataSetChanged() is meant to be called from the outside when you change the items of collection used in the Adapter (values in your case):

   values[5] = "My changed item";
   
   adapter.notifyDataSetChanged();
   

As Steve Jobs would say: 'You're holding it wrong' ;)