wrong second argument type Found andriod.content.Dialoginterface.onClicklistener, required andrid.content.Context

Question

Hello I'm trying to get an list of classes to be saved so when the app is closed and reopened the content will still be there. I tried to save the array to another java page but I keep getting this error.

//Main Java
    builder.setPositiveButton("Add Class", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    String ClassesAdded = ClassET.getText().toString();
                    adapter.add(ClassesAdded);
                    ClassET.setText("");
                    **FileHelper.writeData(classarray, this);//line giving me error**


            }
        });

//FileHelper
public class FileHelper {
    public static final String FILENAME = "listinfo.dat";
    public static void writeData(ArrayList<String> classarray, Context context){
        try {
            FileOutputStream fos = context.openFileOutput(FILENAME, Context.MODE_PRIVATE);
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(classarray);
            oos.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

Answer 1

That error is because this refers to the OnClickListener in that scope but the function expects a Context. If your activity (wherever the builder call is) is named MainActivity you would need to use MainActivity.this there to use the right class instance, like this:

FileHelper.writeData(classarray, MainActivity.this);

Obviously replace MainActivity with your actual class name if that's not what it's called...