Listening to events


DUI
D GTK+ binding

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See the old (and still more complete) way of listening to events at
Old Listener interfaces

Warning:
Not all events are implemented.
Listening to Combo, Entry component for the second time will segfault the application.
Note:
DUITests still uses the listener interfaces to listen to events on most of it's examples
leds uses exclusivly delegates to listen to events.

Listening to events

You can now add a delegate to a widget to process the events on that widget.
Every widget class inherits the events from it's parent class.

To add a delegate to an event callback:
add<eventName>(delegate);
There is no way to remove a listener yet
on the future do remove<eventName>(delegate);

for instance a button has the events:

  • OnClick
  • OnButtonClicked
  • OnButtonPressed
  • OnButtonReleased
  • OnButtonEnter
  • OnButtonLeave
  • OnButtonActivate
  • plus the Bin events (none implemented)
  • plus the Container events (none implemented)
  • plus the Widget events (most implemented)

to add a delegate to these events:

  • button.addOnClick(&delegate);
  • button.addOnButtonClicked(&delegate);
  • button.addOnButtonPressed(&delegate);
  • button.addOnButtonReleased(&delegate);
  • button.addOnButtonEnter(&delegate);
  • button.addOnButtonLeave(&delegate);
  • button.addOnButtonActivate(&delegate);

all the delegates are:
void delegate(Button);
except for OnClick that is
void delegate()
(onClick and OnButtonClicked are callbacks to the same event)

OnClick special case
OnClick is a higher level callback to onButtonClicked
and has a more convenient usage:

  • buttons and menu items can be created with the onCLick delegate:
    • new Button(Stock.OK, &onOKClickDelegate);
    • new MenuItem("Stock.Exit, &onExitClickDelegate);
  • onClick is public so that it can be used like:
    • button.onClick +=
    • menuItem.onClick +=

here is an example for the common button click: 

 void someFunction()
 {
     Button button;
     button = new Button(Stock.OK);
     buttonOK.addOnButtonClicked(&doOK);
onClick is another way of adding a delegate to the button click event 
     button = new Button(Stock.CANCEL);
     button.addOnClick(&doCancel);
the onClick is public and can be used: 
     button.onClick += doCancel;
the event delegate can be passed to the button constructor 
     new Button("My Button", myButtonClicked);
     
 }
the OnButtonClicked delegate 
 void doOK(Button button)
 {
     printf("button OK was clicked\n");
 }
the OnClick delegate
notice no parameters for the onCLick event 
 void doCancel()
 {
     printf("button CANCEL was clicked\n");
 }


 void myButtonClicked()
 {
     printf("myButton was clicked\n");
 }

DUI events follow the GTK events
The implemented widget events are:
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