Random number generation with random operators

Question

I am new to android development and currently working on a simple app which, among other things, needs to generate random numbers with random operators (+, -, *, /) every time. I have a "generate" button which is supposed to give different questions every time it is pressed. I know how to generate random numbers, but I don't know how to generate the random operators so that the question is different every time. I tried using a switch statement but not successful so far (or I'm missing code in it). Can anyone help? Thanks in advance.

Here is the code i have thus far:

private void goGenerate() {

    num1 = (int)(Math.random()*10) + 1;
    num2 = (int)(Math.random()*10) + 1;
    generate();
}

private void generate() {
    StringBuilder equation = new StringBuilder();
    goGenerate();

    operator = (int)(Math.random() *4 ) + 1;

    equation.append(num1);
    if(operator == 1) {
        equation.append("+");
        result = num1 + num2;
    }
    else if(operator == 2) {
        equation.append("-");
        result = num1-num2;
    }
    else if(operator == 3) {
        equation.append("*");
        result = num1 * num2;
    }
    else if(operator == 4) {
        equation.append("/");
        while((num1 % num2 != 0) && (num1 < num2)) {
            generate();
        }
        result = num1 / num2;
    }

    textViewOperation.setText(operator);

Answer 1

Make two random routines, one for your number and one, restricted to 0-3, where you associate each of the possible numbers (0 to 3) to an operator. Then it's done. Good luck.

EDIT (this works):

int operator, num1, num2, result;
StringBuilder equation;

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final TextView tv1 = (TextView) findViewById(R.id.tv1);
    tv1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            generate();
            tv1.setText(String.valueOf(result));
        }
    });

}



private Integer generate() {

    equation = new StringBuilder();
    num1 = (int)(Math.random()*10) + 1;
    num2 = (int)(Math.random()*10) + 1;

    operator = new Random().nextInt(4);

    equation.append(num1);
    if (operator == 1) {
        equation.append("+");
        result = num1 + num2;
    } else if (operator == 2) {
        equation.append("-");
        result = num1 - num2;
    } else if (operator == 3) {
        equation.append("*");
        result = num1 * num2;
    } else if (operator == 4) {
        equation.append("/");
        while ((num1 % num2 != 0) && (num1 < num2)) {
            generate();
        }
        result = num1 / num2;
    }
    return result;
}}