xojo:objectnotifier:start

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xojo:objectnotifier:start [2021/04/01 15:53]
mz 		xojo:objectnotifier:start [2021/04/06 07:27] (aktuell)
mz [Object notification]
Zeile 1: Zeile 1:
-====== Object Notification ====== +====== Object notification ======
-/* {{tag> }} */+
  
-{{indexmenu>.#3|ns tsort hsort nsort}}+<fs x-large>A simple subscribe-callback mechanism for inter-object communication</fs> 
 + 
 +<WRAP round download 40%> 
 +**{{ :xojo:objectnotifier:object_notification.zip |Object Notification interfaces and class  (xojo-binary-code folder)}}**\\ 
 + 
 +{{ :xojo:objectnotifier:objectnotification.pdf |Sourcecode as pdf}} 
 +</WRAP> 
 + 
 + 
 +This works similar to the built-in interfaces //dataNotifier// and //dataNotificationReceiver//.\\ 
 +However the **ObjectChanged** method receives two parameters: an **Object** from the notifier and any **info** from the original subscriber.\\ 
 + 
 +The **notifier** may send himself by setting "me" as Object, or he sends simply the current data which have been changed.\\ 
 +The **subscriber** stores any sort of (static) information together with the callback-address when subscribing by //addObjectNotificationReceiver//.\\ 
 +This info may be a simple index number, but it can also be a whole object (means a reference to an object) so that the receiver can distinguish which subscription called him. 
 + 
 +The **//ObjectNotifierBox//** contains the complete implementation of the //objectNotifier// interface.\\ 
 +Simply instantiate this class and call their members like: 
 + 
 +Declare: 
 +  private property onb as ObjectNotifierBox 
 +in //Constructor// Method: 
 +  onb = new ObjectNotifierBox  
 +Actual implementation of the //objectNotifier// Interface: 
 +  Sub addObjectNotificationReceiver(receiver as objectNotificationReceiver, optional info as Variant = nil) 
 +     onb.addReceiver(receiver, info) 
 +  End Sub 
 + 
 +  Sub removeObjectNotificationReceiver(receiver As objectNotificationReceiver) 
 +     onb.removeReceiver(receiver) 
 +  End Sub 
 + 
 +For calling all subscribed receivers write somewhere in your class: 
 + 
 +  onb.callReceivers(me) 
 + 
 +Instead of "me" you may send any object you need, of course... 
 + 
 +<WRAP round important 100%> 
 +Be careful with //removing// if you have multiple subscriptions from the same object (perhaps with different //info//).\\ 
 +<code> 
 +xy.addObjectNotificationReceiver(me, 1) 
 +xy.addObjectNotificationReceiver(me, 2) 
 +</code> 
 +Because //removeObjectNotificationReceiver// obtains no //info// parameter, it cancels only the first object found in the array, thus acting as //fifo//.\\ 
 +It's therefore not possible to delete only the second entry (with //info// 2). 
 + 
 +</WRAP> 
 + 
 + 
 + 
 +====== Sourcecode ====== 
 + 
 +{{ :xojo:objectnotifier:objectnotification-tree.png|}}
  
----- 
  
 ===== Interface objectNotifier ===== ===== Interface objectNotifier =====
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   Properties   Properties
      
-  mInfos() As Variant +  Private mInfos() As Variant 
-  mReceivers() As objectNotificationReceiver+  Private mReceivers() As objectNotificationReceiver
      
   End Class   End Class
  • xojo/objectnotifier/start.1617292389.txt.gz
  • Zuletzt geändert: 2021/04/01 15:53
  • von mz