Calling a Controller (SAP Library - Model View Controller Tutorial)

Calling a Controller

Use

You can call a controller from a page with flow logic, or from a view.

Procedure

Create a page within your BSP application.

Ensure that you select Page with Flow Logic as the page type.

In the Tag Browser, select BSP extension bsp and drag it to the second line of your BSP’s layout under the page directive.

This graphic is explained in the accompanying text

Now drag the <bsp:goto> directive of BSP extension bsp to the body of the HTML layout and add the URL parameter.

The source now looks as follows:

<%@page language="abap"%>

<%@ extension name="bsp" prefix="bsp" %>

<html>

  <head>
    <link rel="stylesheet" href="../../sap/public/bc/bsp/styles/sapbsp.css">
    <title> Initial page </title>
  </head>

</html>

You can now activate and test the page.

The page looks as follows:

This graphic is explained in the accompanying text

Note

Ensure that the page you have tested looks exactly the same as when you tested the controller. The URL is different, however. You can use View Source in the browser to see that nothing remains of the HTML text from the BSP, but that only the content of the view is displayed:

<html>

<head>

<title> Layout for Controller </title>

</head>

</head>

<H1>View Example</H1>

<H3>Hello, User GREBEL</H3>

</body>

</html>

You can now try out the difference between the <bsp:goto> element and the <bsp:call> element.

If you use the <bsp:call> element instead of the <bsp:goto> element, the calling page text remains the same. In the view that is inserted, you should therefore delete the HTML text available on the outline page, otherwise these texts will be transferred twice.

You can add another attribute to the controller. This is a public class attribute.

It is set using the <bsp:parameter> element. You can use it for example to control which view is called, or this value can be passed to the view.