Step 3 - Converting a UI when not using other frameworks
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Note
| This step is needed in case your Vaadin 7 or 8 application doesn’t use Spring Boot, CDI or Navigator. If it uses any of those, go back to the framework selection. |
Converting UIs
When not using a Navigator, you can replace the UI class with a Flow component
by changing init(VaadinRequest) to a constructor and have UI.setContent to be
add(new LegacyWrapper(content)) instead.
Also remember to register Route for the class.
For example, this code:
@Theme("valo")
public class AddressbookUI extends UI {
private HorizontalLayout content = new HorizontalLayout();
@Override
protected void init(VaadinRequest vaadinRequest) {
content.setSizeFull();
setContent(content);
}
}Should be converted to this:
@Route("")
public class AddressbookLayout extends Div {
private HorizontalLayout content = new HorizontalLayout();
public AddressbookLayout() {
content.setSizeFull();
add(new LegacyWrapper(content));
}
}|
Note
|
Annotations in the UI, such as @Theme and @Title and so on, are dealt with later on in the tutorial.
Most of them have similar counterpart in either Flow or MPR.
|
To make the code look less busy you can also implement the
HasLegacyComponents
interface so you don’t need to use new LegacyWrapper.
@Route("")
public class AddressbookLayout extends Div implements HasLegacyComponents {
private HorizontalLayout content = new HorizontalLayout();
public AddressbookLayout() {
content.setSizeFull();
add(content);
}
}