Step 6: Modules

In SAPUI5, resources are often referred to as "modules". In this step, we replace the alert from the last exercise with a proper "Message Toast" from the sap.m library. The required modules are enabled to be loaded asynchronously.

Preview

Figure 1: A message toast displays the "Hello World" message

Coding

You can view and download all files in the Explored app in the Demo Kit under Walkthrough - Step 6.

webapp/controller/App.controller.js

sap.ui.define([
   "sap/ui/core/mvc/Controller",
   "sap/m/MessageToast"
], function (Controller, MessageToast) {
   "use strict";
   return Controller.extend("sap.ui.demo.wt.controller.App", {
      onShowHello : function () {
         MessageToast.show("Hello World");
      }
   });
});

We extend the array of required modules with the fully qualified path to sap.m.MessageToast. Once both modules, Controller and MessageToast, are loaded, the callback function is called and we can make use of both objects by accessing the parameters passed on to the function.

This Asynchronous Module Definition (AMD) syntax allows to clearly separate the module loading from the code execution and greatly improves the performance of the application. The browser can decide when and how the resources are loaded prior to code execution.

Conventions

Use sap.ui.define for controllers and all other JavaScript modules to define a global namespace. With the namespace, the object can be addressed throughout the application.
Use sap.ui.require for asynchronously loading dependencies but without declaring a namespace, for example code that just needs to be executed, but does not need to be called from other code.
Use the name of the artifact to load for naming the function parameters (without namespace).