As @HFOE suggests, InputVerifier
is the right choice, but verify()
“should have no side effects.” Instead, invoke calcProduct()
in shouldYieldFocus()
.
/**
* @see http://stackoverflow.com/a/11818946/230513
*/
private class MyInputVerifier extends InputVerifier {
private JTextField field;
private double value;
public MyInputVerifier(JTextField field) {
this.field = field;
}
@Override
public boolean shouldYieldFocus(JComponent input) {
if (verify(input)) {
field.setText(String.valueOf(value));
calcProduct();
return true;
} else {
field.setText(ZERO);
field.selectAll();
return false;
}
}
@Override
public boolean verify(JComponent input) {
try {
value = Double.parseDouble(field.getText());
return true;
} catch (NumberFormatException e) {
return false;
}
}
}