In view, there are extension points, similarly in
controllers, there are hooks. Hooks are extension points in the controller code
that are used to make controller extensions more stable. The controller extension concept enables you
to override any method. This is a powerful but also fragile feature. Extension
points, so-called Hooks, can be
provided in the controller code. These hooks can be documented and kept stable,
thus providing more robust hooks across application updates for controller
extensions.
Let me just explain the steps for providing hooks in the
controller:
1) Identify a position, where you want to plug in and
execute their customized code.
2) In the application, define a new function name which
is reserved for the extension, document the function and any arguments the
function may receive or return.
3) Add code lines in the application (see code snippet
below) to check whether the function has been implemented, and, if so, to call
the function.
4) You can then configure a controller extension,
implementing exactly this one function.
5) SAPUI5 runtime merges the new
controller extension into the standard controller. If customizing is enabled,
the new function can be executed.
Example
By receiving the data object oSomeData
from the server, the application enables you to access and modify the data
object. The extension function name is onDataReceived
and gets a reference to the data object as argument.
Code of the standard controller:
//
...data object oSomeData has been received, possibly from an Ajax response...
if
(this.onDataReceived) { // check
whether any extension has implemented the hook...
this.onDataReceived(oSomeData);
// ...and call it
}
//
...continue working with the (now possibly modified) data...
Code of the custom controller:
sap.ui.controller("customer.xy.Sub2ControllerExtension",
{
onDataReceived:
function(oData){ // oSomeData will be passed in
if
(oData && oData.status === "important") {
oData.message
= oData.message + "!!!"; // modify some part of the data object,
adding exclamation marks to a message text
}
}
// no need to return anything as in this example the original object is
modified
});
Controller Replacement
Standard
controller can be replaced by specifying a new controller name in a replacement
View and implementing this Controller.
For a view
replacement, you can either use the standard controller of the replaced view by
setting its name as controllerName, or use or extend the standard controller, or you can replace the
controller by specifying a new controller name in the new view and implementing
the new controller.
Follow my next blog for an example on extending app using
SAP Web IDE.
This is dummy text. It is not meant to be read. Accordingly, it is difficult to figure out when to end it. But then, this is dummy text. It is not meant to be read. Period.
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