mvc - adding views to main GUI frame

[Jonathan Janisch]

Hi. I just read Head First Design Patterns (it's an awesome book!). In the chapter on MVC, it says the controller creates the view. This works great for their example, because their view is the main JFrame. In my case, my views are components I want to add to my existing JFrame.

I have the EXACT same problem as this guy and oddly enough he also just read the same book:

http://forum.java.sun.com/thread.jspa?forumID=425&threadID=5138897

but I don't necessarily understand the answer he was given.

So, since he's better at explaining it, I'm going to quote his post:

Hi,

If I have a a couple of different Views which are created by a couple of different controllers what would be the best way of adding these to a main frame.

For example

View1 extends JPanel
View1Controller creates it.

View2 extends JPanel
View2 Controller creates it.

MainFrame extends JFrame

currently I have the controllers returning the View that they create so I can add them like so


getContentPane().add(controller1.getView1());
getContentPane().add(controller2.getView2());



This however does not sit right with me, though I'm not sure why.

Does anybody have any thoughts or insights on the above.

In addition to his question, should my main JFrame be creating controller1 and controller2? Or should this be done in non-gui code and passed into the MainFrame constructor?

i.e.

class MainFrame {
   public MainFrame() {
      controller1 = new View1Controller();
      controller2 = new View2Controller();
      getContentPane().add(controller1.getView());
      getContentPane().add(controller2.getView());
   }
}

or should I do this:

// Main.java
View1Controller controller1 = new View1Controller();
View2Controller controller2 = new View2Controller();
MainFrame frame = new MainFrame(controller1,controller2);
 
// MainFrame.java
class MainFrame {
   public MainFrame(View1Controller controller1, View2Controller controller2) {
       this.controller1 = controller1;
       this.controller2 = controller2;
       getContentPane().add(controller1.getView());
       getContentPane().add(controller2.getView());
   }
}

I believe the first approach is better as long as the MainFrame is allowed to create the controllers. With the second approach, if I have 10 controllers, these all have to be passed to the MainFrame constructor. Or are none of these approaches correct?

I'm open to any advice. I feel like I'm closer than ever to understanding MVC thanks to HFDP, so thanks if you were involved with that book.

[Campbell Ritchie]

Welcome to the Ranch

Is this recent article from the Java Developers' Series any use to you?

[Jonathan Janisch]

Thanks.

That did help. I'm not quite sure if I like their modified MVC approach, but I can use the part where they add the views to the controller.

[Campbell Ritchie]

You're welcome.