Controller Extension

SAPUI5 supports the extension of a base controller by merging the delivered standard controller with a custom controller on JavaScript object level.

The SAPUI5 controller extension concept does not use inheritance. Instead, methods of the custom controller override standard methods with the same name. The following controller lifecycle methods are, however, an exception to this rule: onInit, onExit, onBeforeRendering, onAfterRendering. For these methods, the controller methods of your custom application are called either after (for onInit and onAfterRendering), or before (for onExit and onBeforeRendering) the standard lifecycle methods.

The following examples show, how controller extension concept in SAPUI5 works. The following code snippet shows the standard controller Main.controller.js of the delivered standard application:

sap.ui.controller("samples.components.ext.sap.Main", {
    onInit : function () {
        console.log("samples.components.ext.sap.Main - onInit");
    },

    doSomething: function() {
        alert("this is an original standard action");
    },

    doSomeStandardAction: function() {
        alert("this is another original standard action");
    }
});

The following code snippet represents the custom controller CustomMain.controller.js:

sap.ui.controller("samples.components.ext.customer.CustomMain", {
    onInit : function () {
        console.log("samples.components.ext.customer.CustomMain - onInit");
    },

    doSomething: function() {
        alert("this is a customer action");
    },

    doSomeCustomAction: function() {
        alert("this is another customer action");
    }
});

The following customizing merges the two controllers:

customizing: {  
    "sap.ui.controllerExtensions": {
        "samples.components.ext.sap.Main": {
            controllerName: "samples.components.ext.customer.CustomMain"
        }
    },
    .....some more content

As a result, the samples.components.ext.customer.CustomMain controller functions are merged when the controller samples.components.ext.sap.Main is called. After initialization, the log contains the following messages:

samples.components.ext.sap.Main - onInit
samples.components.ext.customer.CustomMain - onInit

The doSomething method of the new controller overwrites the doSomething method of the standard controller. Thus, if the method is invoked, an alert popup with the following text appears: this is a customer action.

The doSomeStandardAction method remains available without changes, as no method with the same name exists in the new controller.

The doSomeCustomAction method is additionally available and you can use it, for example, in a view extension.

The controller extensions are applied to all controllers with the specified name within the customized component, regardless of whether the controller is instantiated explicitly or belongs to a view.