How do I make my Calculate button redundant?

I have a simple Android app that does some math on 2 numbers that the user inputs and returns the result. Currently I have a 'calculate' button that needs to be pressed to do the math and return the value.

How can I get rid of this button and just get the app to run the math after the uses has changed either one of the 2 numb开发者_C百科ers?

Many thanks.

---

Assuming that you are using EditText-s for the input (because they could be SeekBar-s, who knows), add on each one of them a TextWatcher with this and after each change of one of them refresh the result

---

I used something like this for an EditText field that I wanted to be auto-updated after changing some other EditText fields:

    myEditText.setOnEditorActionListener(new TextView.OnEditorActionListener() {
        @Override
        public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
            if (actionId == EditorInfo.IME_ACTION_DONE)
            {
                calculateNewValue();   // Updates internal variables

                // This part will hide the keyboard after input
                InputMethodManager imm = (InputMethodManager)getSystemService(INPUT_METHOD_SERVICE);
                imm.hideSoftInputFromWindow(v.getWindowToken(), 0);
                return true;
            }
            return false;
        }
    });

This also hides the keyboard when you're done (thanks to a bit of help).

The calculateNewValue() updated the field like this:

private void calculateNewValue()
{
    val = YourFormula()

    myEditText.setText(String.format(yourFormat, val))
}

---

The details depend on what language you are using, but basically you could just run the calculation function whenever either one of the numbers is changed. There should be a way to override the function that is called when the data in either text box has changed.

---

Well, if both numbers start off with 0, you can either check to make sure neither or 0 or trigger the math when both text fields have received text changed events. I'm not sure what platform you are using so I can't give you much more info.