Event Handling Question


DevX Home    Today's Headlines   Articles Archive   Tip Bank   Forums   

Results 1 to 2 of 2

Thread: Event Handling Question

Hybrid View

  1. #1
    Edward Guest

    Event Handling Question


    Something about the AWT event model is puzzling me. Scenario: A button component
    has registered an event listener (implementing a MouseAdapter, for instance).
    Now, the Listener is implementing, say, two or three methods (mouseClicked,
    mouseExit, etc.). When the mouse clicks on the button, or exits the button,
    this "Event" is passed to the appropriate method implemented in the Listener
    (then handled in some way).

    All that is fine and dandy. But my questions...

    What is actually generating the original event? I read things like, "The
    AWT passes the event to the component(button)." If that is the case, and
    the button isn't generating the event object, then what in the AWT is? Also,
    once the event object exists, how does the button know which method in the
    Listener to call? It's passing (or forwarding the event object) but how
    does it know it should pass it to mouseClicked, or mouseExit, etc.?

    Any help or explanation is greatly appreciated!

    Ed
    (note: also posted in AWT message board)

  2. #2
    bhupesh Guest

    Re: Event Handling Question


    "Edward" wrote:
    >
    >Something about the AWT event model is puzzling me. Scenario: A button

    component
    >has registered an event listener (implementing a MouseAdapter, for instance).
    > Now, the Listener is implementing, say, two or three methods (mouseClicked,
    >mouseExit, etc.). When the mouse clicks on the button, or exits the button,
    >this "Event" is passed to the appropriate method implemented in the Listener
    >(then handled in some way).
    >
    >All that is fine and dandy. But my questions...
    >
    >What is actually generating the original event? I read things like, "The
    >AWT passes the event to the component(button)." If that is the case, and
    >the button isn't generating the event object, then what in the AWT is?

    Also,
    >once the event object exists, how does the button know which method in the
    >Listener to call? It's passing (or forwarding the event object) but how
    >does it know it should pass it to mouseClicked, or mouseExit, etc.?
    >
    >Any help or explanation is greatly appreciated!
    >
    >Ed
    >(note: also posted in AWT message board)

    *Awt sends action event to button which is clicked
    *for processing this event button has to be registered
    *new Button().addButtonListener(this) will register button for this object
    & passes its reference to awt
    *functions like processActionEvent(java.awt.ActionEvent )
    1)processes this event & dispatches to registered listener
    2)invoked only when ActionListener object is registered or
    ActionEvents are enabled by enableEvents
    *Button object calls all methods in interface class 1 at a time
    & thus do processing for all methods
    *whatever methods u dont require u can give their body as blank
    if u implement interface or either extend from adapter classes
    & override only those methods u require & leave other to super class

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
HTML5 Development Center
 
 
FAQ
Latest Articles
Java
.NET
XML
Database
Enterprise
Questions? Contact us.
C++
Web Development
Wireless
Latest Tips
Open Source


   Development Centers

   -- Android Development Center
   -- Cloud Development Project Center
   -- HTML5 Development Center
   -- Windows Mobile Development Center