Answer 1

In the Activity where you are using this layout XML, you would do this:

private EditText input;
private EditText result;

public void onCreate(Bundle b) {
    setContentView(R.layout.my_activity);

    // Extract the text fields from the XML layout
    input = (EditText) findById(R.id.input1);
    result = (EditText) findById(R.id.result);

    // Perform calculation when input text changes
    input.addKeyListener(new View.OnKeyListener() {
        public boolean onKey(View v, int keycode, KeyEvent keyevent) {
            if (keyevent.getAction() == KeyEvent.ACTION_UP) {
                doCalculation();
            }
            return false;
        }
    });
}

private void doCalculation() {
    // Get entered input value
    String strValue = input.getText().toString;

    // Perform a hard-coded calculation
    int result = Integer.parseInt(strValue) * 2;

    // Update the UI with the result
    result.setText("Result: "+ result);
}

Note that the above includes no error handling: it assumes that you have restricted the input1 text field to allow the input of integer numbers only.

Answered by: Jared300 | Posted: 25-02-2022

Answer 2

In your XML you can also set android:inputType="number" to only allow numbers as entries.

Answered by: Rafael960 | Posted: 25-02-2022

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