@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mEditText = (EditText)findViewById(R.id.editText);

        Context context = getApplicationContext();
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
        SharedPreferences.OnSharedPreferenceChangeListener listener = (new SharedPreferences.OnSharedPreferenceChangeListener() {
            @Override
            public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
                if (key.equals("cat_food")) {
                    String catFood = sharedPreferences.getString(key, "");
                    catFood = catFood + "\n";

                    String myText = mEditText.getText().toString();
                    Toast.makeText(getApplicationContext(), myText, Toast.LENGTH_SHORT).show();
                    myText = myText + catFood;
                    Toast.makeText(getApplicationContext(), myText, Toast.LENGTH_SHORT).show();
                    mEditText.setText(myText);
                    Toast.makeText(getApplicationContext(), mEditText.getText().toString(), Toast.LENGTH_SHORT).show();
                }
            }
        });
        sharedPreferences.registerOnSharedPreferenceChangeListener(listener);
    }