Replace numbers by letters inside the ArrayList

I'm creating a calculator where, I want the numbers inside ArrayList , to be replaced with letters in textView .

Example: 1 = A , 2 = B , etc.

With the code below, I got this by typing the numbers. That is, textView appear letters instead of numbers.

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

ArrayList<String> arrayList = new ArrayList<String >();
String string = "";
String string1 = "";
String string10 = "A";
String string2 = "B";
String string3 = "C";
String string4 = "D";
String string5 = "E";
String string6 = "F";
String string7 = "G";
String string8 = "H";
String string9 = "I";
String string0 = "J";


public void onClick1 (View v) {
    TextView textView3 = (TextView) findViewById(R.id.caracteres);
    Button button = (Button) v;

    string = (String) button.getText().toString();

    if (!string.contains("+") && !string.contains("-") && !string.contains("*") && !string.contains("/")) {

        if (string.contains("2")) {
            string1 = string1+string2;
        }

        if (string.contains("3")) {
            string =string3;
        }

        if (string.contains("4")) {
            string =string4;
        }

        if (string.contains("5")) {
            string =string5;
        }

        if (string.contains("6")) {
            string =string6;
        }

        if (string.contains("7")) {
            string =string7;
        }

        if (string.contains("8")) {
            string =string8;
        }

        if (string.contains("9")) {
            string =string9;
        }

        if (string.contains("0")) {
            string =string0;
        }
    }

    textView3.setText(textView3.getText().toString() + string);

  

However, in the result, I could not replace, it always remains the numbers, I've tried everything.

public void onClick (View v) {
    int calc= 0;
    int c = arrayList.size();



    TextView textView3 = (TextView) findViewById(R.id.caracteres);

    if (arrayList.contains("8")) {
        string =string8;
    }


    //eg: array (2,+,3,*,4,-,3) size = 7, so (2,+,3,*,4,-,3)

    while (c!=1){

        if (c>3) {
            if (arrayList.get(3).contains("*") || arrayList.get(3).contains("/")) {
                if (arrayList.get(3).contains("*")) {calc = Integer.parseInt(arrayList.get(2))*Integer.parseInt(arrayList.get(4));}
                if (arrayList.get(3).contains("/")) {calc = Integer.parseInt(arrayList.get(2))/Integer.parseInt(arrayList.get(4));}

                //calc = 12 ;array = (2,+,3,*,4,-,3)

                arrayList.remove(2); // (2,+,+,*,4,-,3)
                arrayList.remove(2); // (2,+,3,*,4,-,3)
                arrayList.remove(2); // (2,+,+,-,3)
                arrayList.add(2, Integer.toString(calc)); // (2,+,12,-,3)
                c= arrayList.size(); // size 5

            }

            else {
                // (2,+,12,-,3)
                if (arrayList.get(1).contains("+")) {calc = Integer.parseInt(arrayList.get(0))+Integer.parseInt(arrayList.get(2));}
                if (arrayList.get(1).contains("-")) {calc = Integer.parseInt(arrayList.get(0))-Integer.parseInt(arrayList.get(2));}
                if (arrayList.get(1).contains("*")) {calc = Integer.parseInt(arrayList.get(0))*Integer.parseInt(arrayList.get(2));}
                if (arrayList.get(1).contains("/")) {calc = Integer.parseInt(arrayList.get(0))/Integer.parseInt(arrayList.get(2));}
                    // calc = 14
                arrayList.remove(0); // (+,12,-,3)
                arrayList.remove(0); // (12,-,3)
                arrayList.remove(0); // (-,3)
                arrayList.add(0, Integer.toString(calc)); // (12,-,3)
                c = arrayList.size(); // size = 3

            }

        }
            //size <= 3

        else {

            if (arrayList.get(1).contains("+")) {calc = Integer.parseInt(arrayList.get(0))+Integer.parseInt(arrayList.get(2));}
            if (arrayList.get(1).contains("-")) {calc = Integer.parseInt(arrayList.get(0))-Integer.parseInt(arrayList.get(2));}
            if (arrayList.get(1).contains("*")) {calc = Integer.parseInt(arrayList.get(0))*Integer.parseInt(arrayList.get(2));}
            if (arrayList.get(1).contains("/")) {calc = Integer.parseInt(arrayList.get(0))/Integer.parseInt(arrayList.get(2));}
                // calc = 9
            arrayList.remove(0); //(-,3)
            arrayList.remove(0); //(3)
            arrayList.remove(0); //()
            arrayList.add(0, Integer.toString(calc)); //(9)
            c = arrayList.size(); // size = 1 since is 1 loop ends.
            arrayList.add(string);
        }
    }


    textView3.setText(Integer.toString(calc));


}