Create a Composite Component (List with Rating)

1. Go to the SAP Build lobby, and click Create.

   

   Select SAP Build Apps, and then Build an Application.

   

   Select Web & Mobile Application.

   

   For the project name, enter Social Media, then click Create.

   You will get a skeleton project, with a page, a title component, and a text component.

   SAP Build Apps lets you create apps by dragging and dropping components onto the canvas, and then configuring those components by changing, for example, the text in a text component or the image to display in an image component.

2. Select the text component, and delete it.

   

3. Change the text of the title to Products.

   

4. Click on an open area in the canvas, and in the Properties tab, change the name of the page to List of Products.

Your app should look like this:

You will make a custom component based on 2 components from the component marketplace, a rich source of more complex components for your apps. You will need to install those components first.

1. In the components area, click Marketplace.

   

2. Search for star rating, and click on the component thumbnail.

   

   Click Install (right).

   The component will now be in the Installed tab.

   

3. In the Installed tab, find the Large Image List Item, click the 3 dots, and select Duplicate template.

   

   Do the same for the Star Rating.

   Click Save (upper right).

   You should now have a copy of both components in the By Me tab.

   

   You can now make any changes you want to the components under By Me and the originals will not be changed.

Our goal is to both show a list of products, and also to show a rating for each. To do this, you will take the 2 installed components and put them together.

1. Drag a Large Image List Item onto the canvas from the By Me tab.

2. While the component is selected, open the Component template editor (at the bottom of the Properties pane).

   

   Template Editor

   The template editor lets you make changes to existing components – add components, change component properties, add internal properties and bindings. The stripes in the canvas indicate you are in the template editor.

   

   The template editor lets you make changes to existing components, but the changes will affect all such components in the current project. That is why we made a duplicate, in case we would want to use the original version.

3. In the template editor, select the paragraph component and delete it.

   

4. In the Tree view (bottom right), under the Title, add a container, a star rating (from By Me tab), and 2 text components, according to this hierarchy:

   

   On the canvas, the component should look like this:

   

5. Select Container 2, and set the layout to horizontal, and align components to vertically to bottom.

   

   In the Layout tab, set its width to Fit to content.

6. Select the star rating component, and set the Maximum value property to 5.

In the next step we will continue to work in the component template editor.

Tree View

The tree view is indispensible for making sure your hierarchy of components is OK (e.g., components are within a container).

Consider renaming the components you drag onto the canvas, so when viewing the tree view you can tell what they are for. The component name is under the Properties tab, under the Advanced section.

We want the component to show the rating and rating count for each of the products, so we need properties to hold this data.

1. Open Properties.

   

2. Click Properties (on the left), and add the following properties:

   Field	Type
   Rating	Number
   RatingCount	Number

   

3. Go back to View.

4. Select the first text component, and set the Content property to the following formula:

   JavaScript Copy

   FORMAT_LOCALIZED_DECIMAL(internalProps.Rating, "en", 1,1)

   

   Under Layout, set the width to be exactly 40px wide (select Exact size and enter 40).

   

5. Select the second text component, and set the Content property to the following formula:

   JavaScript Copy

   "(" + internalProps.RatingCount + ")"

   Under Layout, set the width to be exactly 40px wide.

6. Select the star rating component inside our composite component.

   Open the component template editor for our embedded star rating component.

   

   • In the Tree view, expand the nodes and select Icon: Full.

     

     Under Style, edit the Primary Icon style.

     

     Change the color binding type to static color, enter the color #F0AB00, then click Overwrite.

     

   • Select Properties, then Properties on the left side, and then select the Value property.

     

     In the Properties pane, set Two-way binding? to No.

     Click Exit.

7. We still need to make a binding change within the composite component – set the rating component value to the component’s Rating property – so we need to open the template editor for the composite component.

   So, again, select the composite component, and reopen the component template editor.

   

   Select the star rating, and set the Value property to the following:

   Component properties > Composite component internal property > Rating

   Click Save.

   

8. Click Exit (from the component template editor), and then Save (upper right).

Styles

When we changed the color of the stars to orange, we clicked Overwrite, which meant we changed it for the Primary Icon style, which affects all icons.

We could have instead clicked New Style and created a new style, which we could then apply to any icon we wanted orange. All other icons would remain the default style.

The new style would now be in the list of styles you could choose for the current component type.