Question

I need to format the string entered by the user on a EditField.
This is my code:

input = new BorderedEditField(20, BasicEditField.FILTER_NUMERIC);

input.setChangeListener(new FieldChangeListener() {             
    public void fieldChanged(Field field, int context) {
        input.setText(pruebaTexto(input.getText()));
    }
});

public static String pruebaTexto(String r){
    return r+"0";
}

But it ends on a stackoverflow error caused apparently because of an infinite loop.
What is wrong with the code?

Answer 1

You can prevent the recursion by checking whether this is an internal update.
For Blackberry, this is done by checking the value of context

input.setChangeListener(new FieldChangeListener() {
    public void fieldChanged(Field field, int context) {
        if (context != FieldChangeListener.PROGRAMMATIC) {
            input.setText(pruebaTexto(input.getText()));
        }
    }
});

This is a non-Blackberry-specific solution that will work for any variety of listener:

input.setChangeListener(new FieldChangeListener() {
    private boolean internalCall = false;
    public void fieldChanged(Field field, int context) {
        if (!internalCall) {
            internalCall = true;
            try {
                input.setText(pruebaTexto(input.getText()));
            }
            finally {
                internalCall = false;
            }
        }
    }
});