GWT mvp sample project: cannot call method of presenter

Question

I am using the GWT mvp sample project to create my own mvp application.

I pretty much did what they did, ie defined a Presenter interface and then different presenter classes.

In their code, they are doing something like this in one of the View classes:

@UiHandler("loginButton")
void onClick(ClickEvent e) {
    if (presenter != null) {
        presenter.onLoginButtonClicked();
    }
}

The presenter is injected through this method:

public void setPresenter(IPresenter presenter) {
    this.presenter = presenter;

}

Well duh... turns out, I am unable to call the onLoginButtonClicked, since IPresenter is an interface. They do that in their code. How is this supposed to work?

Answer 1

You have to have a class that implements Presenter interface for this view.

Something like:

public class MyActivity extends AbstractActivity implements MyView.Presenter {}

Then you have a View class:

public interface MyView extends IsWidget {

    public interface Presenter {
        void onLoginButtonClicked();
    }

    void setPresenter(Presenter listener);
}

Finally, you will have an implementation of this view:

public class MyViewImpl extends Composite implements MyView {}

NB: I strongly recommend Activities and Places pattern. It gives a good structure for any app with more than one view, and adds good history support.