Step 21: Data Types

The list of invoices is already looking nice, but what is an invoice without a price assigned? Typically prices are stored in a technical format and with a '.' delimiter in the data model. For example, our invoice for pineapples has the calculated price 87.2 without a currency. We are going to use the SAPUI5 data types to format the price properly, with a locale-dependent decimal separator and two digits after the separator.

Preview

Figure 1: The list of invoices with prices and number units

Coding

You can view and download all files in the Explored app in the Demo Kit under Walkthrough - Step 21.

webapp/view/InvoiceList.view.xml

<mvc:View
   controllerName="sap.ui.demo.wt.controller.InvoiceList"
   xmlns="sap.m"
   xmlns:mvc="sap.ui.core.mvc">
   <List
      headerText="{i18n>invoiceListTitle}"
      class="sapUiResponsiveMargin"
      width="auto"
      items="{invoice>/Invoices}">
      <items>
         <ObjectListItem
		title="{invoice>Quantity} x {invoice>ProductName}"
		number="{
			parts: [{path: 'invoice>ExtendedPrice'}, {path: 'view>/currency'}],
			type: 'sap.ui.model.type.Currency',
			formatOptions: {
				showMeasure: false
			}
		}"
		numberUnit="{view>/currency}"/>
	</items>
   </List>
</mvc:View>

We add a price to our invoices list in the view by adding the number and numberUnit attributes to the ObjectListItem control, then we apply the currency data type on the number by setting the type attribute of the binding syntax to sap.ui.model.type.Currency.

As you can see above, we are using a special binding syntax for the number property of the ObjectListItem. This binding syntax makes use of so-called "Calculated Fields", which allows the binding of multiple properties from different models to a single property of a control. The properties bound from different models are called “parts”. In the example above, the property of the control is number and the bound properties (“parts”) retrieved from two different models are invoice>ExtendedPrice and view>/currency.

We want to display the price in Euro, and typically the currency is part of our data model on the back end. In our case this is not the case, so we need to define it directly in the app. We therefore add a controller for the invoice list, and use the currency property as the second part of our binding syntax. The Currency type will handle the formatting of the price for us, based on the currency code. In our case, the price is displayed with 2 decimals.

Additionally, we set the formatting option showMeasure to false. This hides the currency code in the property number, because it is passed on to the ObjectListItem control as a separate property numberUnit.

webapp/controller/InvoiceList.controller.js (New)

sap.ui.define([
	"sap/ui/core/mvc/Controller",
	"sap/ui/model/json/JSONModel"
], function (Controller, JSONModel) {
	"use strict";

	return Controller.extend("sap.ui.demo.wt.controller.InvoiceList", {

		onInit : function () {
			var oViewModel = new JSONModel({
				currency: "EUR"
			});
			this.getView().setModel(oViewModel, "view");
		}

	});
});

To be able to access the currency code that is not part of our data model, we define a view model in the controller of the invoice list. It is a simple JSON model with just one key currency and the value EUR. This can be bound to the formatter of the number field. View models can hold any configuration options assigned to a control to bind properties such as the visibility.

Conventions

Use data types instead of custom formatters whenever possible.