Routing Interface

Using Routing

Performing the Routing Action

21

The important slot in each frame in the

routeScripts

array is the

RouteScript

slot. This slot contains either a symbol identifying a method, or a

function directly, that is called if the user chooses this action from the Action
picker. This function is where you perform the routing action. The function you
define is passed two parameters, target and targetView, which define the data object
to be routed and the view that contains it, respectively.

The two values, target and targetView, are obtained from your application by the
Routing interface. As soon as the Action button is first tapped, the Routing interface
sends the Action button view the

GetTargetInfo

message to obtain these two

values. The

GetTargetInfo

method returns a frame containing these and other slots.

If you set up and use

target

and

targetView

slots in your views, you don't

need to implement the

GetTargetInfo

method because this is a root view

method that is found by inheritance. The root view method looks for the slots

target

and

targetView

, starting from the receiver of the message, which is the

Action button view. It returns these slots in a frame called the target information
frame. If you don't use these slots in your views, you'll need to implement the

GetTargetInfo

method to return them.

The

RouteScript

slot can contain either a symbol identifying a function or it

can contain a function directly. If you are defining the

routeScripts

array in a

registered view definition, the

RouteScript

slot must contain a function directly.

Alternatively, if your view definition is used only within your application, you can
specify an

appSymbol

slot in the

routeScripts

frame and specify a symbol

for the

RouteScript

slot. The

appSymbol

slot tells the system in what

application to find the method identified by the

RouteScript

slot. Using the

latter alternative ties the view definition to a single application.

Here is an example of how you might define the function identified by the

RouteScript

slot shown in the example frame above:

MyActionFunc: func(target,targetView) begin

targetView:DeleteStuffFunc(target);
end,

Handling Multiple Items

21

The target item, as returned by

GetTargetInfo

, may actually be a multiple-item

target object that encapsulates several individual items to be routed. You can check
if this is the case by using the function

TargetIsCursor

. If the target item is a

multiple-item target object, and you need to act separately on the individual items,
you can obtain a cursor for the items by using the function

GetTargetCursor

.

Then you can use the standard cursor methods

Entry

,

Next

, and

Prev

to iterate

over the cursor and return individual items. For more information about using