I've changed b to Button, but the error changed to
java.lang.IllegalArgumentException: display is null.
as the display is not initialized yet. Namely, I'm doing this during
startup() to define listeners.
The method is called once, but as it is called for each button I wanted
to reduce the number of lines ;-)
by writing a one-liner for each button, and maybe further on, put all
the buttons in a collection and iterate over its members.
It is just reducing the number of lines in code.
Greg Brown said the following on 23/11/2010 19:10:
I noticed that, in the second example, you are passing an instance of
PushButton as b rather than Button. That may be causing the problem,
since the buttonPressed() method takes an instance of Button, not
PushButton.
Also, I'm not sure how you expect to call pressedDo(), but as coded it
will add a new event listener every time it is called. Is that the
intended behavior?
On Nov 23, 2010, at 1:05 PM, Bojan Vučinić wrote:
Hi All,
If you are using Scala for your code then you are obliged to write
listeners in the following way:
printButton.getButtonPressListeners.add(new ButtonPressListener {
override def buttonPressed(b: Button) {
print
}
})
I've tried to simplify this by defining the following method:
def pressedDo (aB: PushButton, action: Unit) = {
aB.getButtonPressListeners.add(new ButtonPressListener {
override def buttonPressed(b: PushButton) { action }})
}
and than invoking the method in this way (example)
pressedDo(printButton, print)
however, this results in a compiler error:
error: object creation impossible, since method buttonPressed in trait
ButtonPressListener of type (x$1: org.apache.pivot.wtk.Button)Unit is not
defined
aB.getButtonPressListeners.add(new ButtonPressListener {
I'm not a programming language specialist, and in addition a Scala
novice, but I'm puzzled why putting boilerplate code in a separate
method is not working??
Best regards,
Bojan
