ui5-typescript-walkthrough

Step 22: Custom Formatters

If we want to do a more complex logic for formatting properties of our data model, we can also write a custom formatting function. We will now add a localized status with a custom formatter, because the status in our data model is in a rather technical format.

Preview

^{A status is now displayed with a custom formatter}

You can access the live preview by clicking on this link: 🔗 Live Preview of Step 22.

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Coding

webapp/i18n/i18n.properties

We add three new entries to the resource bundle that reflect translated status texts ‘New’, ‘In Progess’, and ‘Done’. We will use these texts to format the status values ‘A’, ‘B’, and ‘C’ of our invoices when displayed in the invoice list view.

webapp/i18n/i18n.properties

...
# Invoice List
invoiceListTitle=Invoices
invoiceStatusA=New
invoiceStatusB=In Progress
invoiceStatusC=Done

webapp/model/formatter.ts (New)

We place a new formatter.ts in the model folder of the app. This time we do not need to extend from any base object, but just return an object with our formatter functions in it. We add a statusText function, that gets a status as input parameter and returns a human-readable text that is read from the resourceBundle file.

import ResourceBundle from "sap/base/i18n/ResourceBundle";
import Controller from "sap/ui/core/mvc/Controller";
import ResourceModel from "sap/ui/model/resource/ResourceModel";

export default  {
    statusText: function (this: Controller, status: string): string | undefined {
        const resourceBundle = (this?.getOwnerComponent()?.getModel("i18n") as ResourceModel)?.getResourceBundle() as ResourceBundle;
        switch (status) {
            case "A":
                return resourceBundle.getText("invoiceStatusA");
            case "B":
                return resourceBundle.getText("invoiceStatusB");
            case "C":
                return resourceBundle.getText("invoiceStatusC");
            default:
                return status;
        }
    }
};

The new formatter file is placed in the model folder of the app, because formatters are working on data properties and format them for display on the UI. This time we do not extend from any base object but just return an object with our formatter functions inside.

📌 Important:
In the above example, this refers to the controller instance as soon as the formatter gets called. We access the resource bundle via the component using this.getOwnerComponent().getModel() instead of using this.getView().getModel(). The latter call might return undefined, because the view might not have been attached to the component yet, and thus the view can’t inherit a model from the component.

Additional Information:

webapp/view/InvoiceList.view.xml

To load our formatter functions, we use the require attribute with the namespace URI sap.ui.core, for which the prefix core is already defined in our XML view. This allows us to write the attribute as core:require. We then add our custom formatter module to the list of required modules and assign it the alias Formatter, making it available for use within the view.

We add a status using the firstStatus aggregation to our ObjectListItem that will display the status of our invoice. There we defined our alias Formatter that holds our formatter functions, so we can access it by Formatter.statusText. When called, we want the this context to be set to the controller instance of the current view. To achieve this, we use .bind($controller).

<mvc:View
   controllerName="ui5.walkthrough.controller.InvoiceList"
   xmlns="sap.m"
   xmlns:core="sap.ui.core"
   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: [
                  'invoice>ExtendedPrice', 
                  'view>/currency'
               ],
               type: 'sap.ui.model.type.Currency',
               formatOptions: {
                  showMeasure: false
               }
            }"
            numberUnit="{view>/currency}"
            numberState="{= ${invoice>ExtendedPrice} > 50 ? 'Error' : 'Success' }">
            <firstStatus>
               <ObjectStatus
                  core:require="{
                     Formatter: 'ui5/walkthrough/model/formatter'
                  }"
                  text="{
                     path: 'invoice>Status',
                     formatter: 'Formatter.statusText.bind($controller)'
                  }"
               />
            </firstStatus>
         </ObjectListItem>
      </items>
   </List>
</mvc:View>

Instead of a technical status we get now the human-readable texts per invoice we specified in our resource bundle below the number attribute of the ObjectListItem.

Next: Step 23: Filtering

Previous: Step 21: Expression Binding

Related Information

Formatting, Parsing, and Validating Data

Require Modules in XML View and Fragment

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