AppleEvent Class

AppleEvent objects can be used to communicate with other Macintosh applications and the Macintosh System software. If you are compiling your application for use on other operating systems, be sure to check the global Boolean constants TargetWin32, TargetMacOS, and TargetLinux.

Events

None

Properties

BooleanParam	RecordParam	ReplyPtr
DescListParam	ReplyBoolean	ReplyRecord
DoubleParam	ReplyDescList	ReplySingle
EnumeratedParam	ReplyDouble	ReplyString
FolderItemParam	ReplyEnumerated	SingleParam
IntegerParam	ReplyFolderItem	StringParam
MacTypeParam	ReplyInteger	TimeOut
ObjectSpecifierParam	ReplyMacType
Ptr	ReplyObjectSpecifier

Methods

LoadFromTemplate

Send

SetNullParam

More information available in parent classes: Object

These constants return True if the application is running on the respective operating system.

Notes

AppleEvent objects are used to send and receive information between your application and other Macintosh applications or the Mac OS. To send an AppleEvent from your application to another application, create an AppleEvent with the NewAppleEvent function, fill in the AppleEvent's properties with any necessary data, then call the AppleEvent's Send function to send it.

AppleEvents can also be received by your application. When your application receives an AppleEvent, the Application object's HandleAppleEvent event is executed and the AppleEvent is passed to the event as a parameter. For more information on receiving AppleEvents, see the Application class.

Replying To An AppleEvent

When an AppleEvent is received (via an AppleEvent handler) the ReplyBoolean, ReplyInteger, and ReplyString properties can be used to automatically send a reply back to the application that sent the AppleEvent. When sending an AppleEvent (via the Send method) the ReplyBoolean, ReplyInteger, and ReplyString properties can be used to get any reply the target application has sent back once it receives the AppleEvent.

For example, the line:

e.ReplyBoolean= True

indicates that the application successfully handled the AppleEvent message.

To determine whether the other application successfully handled a message, use code such as:

Dim ae as AppleEvent
Dim s as String
.
.
If ae.Send then //AE successfully sent
If ae.replyBoolean then
  s = "Yes (handled)"
else
  s = "Yes (unhandled)"
  end if
else
s = "No"
end if

For more information on AppleEvents, please refer to Apple's Developer section in the internet.

Examples

This example uses an AppleEvent to tell the Finder to open the Appearance control panel:

Dim a as AppleEvent
a = NewAppleEvent("aevt", "odoc", "MACS")
a.FolderItemParam("----")= SpecialFolder.ControlPanels.Child("Appearance")
If Not a.Send Then
MsgBox "The Appearance control panel could not be opened."
End if

In this example, the SimpleText application (which must be running for this particular example to work) is instructed to open two documents ("My Document" and "My Other Document") that are located in the folder with the REALbasic project:

Dim a as AppleEvent
Dim list as AppleEventDescList
a = NewAppleEvent("aevt", "odoc", "ttxt")
list = New AppleEventDescList
list.AppendFolderItem GetFolderItem("My Document")
list.AppendFolderItem GetFolderItem("My Other Document")
a.DescListParam("----") = list
If Not a.Send Then
MsgBox "The AppleEvent could not be sent."
End If

This example displays the version of the Mac OS that is running on the user's computer:

Dim ae as AppleEvent
Dim obj as AppleEventObjectSpecifier
Dim version as String

If TargetMacOS then
ae = NewAppleEvent("core","getd","MACS")
obj= GetPropertyObjectDescriptor(nil, "ver2")
ae.ObjectSpecifierParam("----") = obj

If Not ae.send() then
   MsgBox "The event could not be sent."
else
  version = ae.ReplyString
  If (version <> "") then
   MsgBox "The system version is apparently """ + version + """."
  else
   MsgBox "This version of the system software does not support this event."
  end if
end if
else
MsgBox "This is not a Macintosh!"
end if