MVC - 模型-视图通信

Question

First of all I want to say that I searched a lot, but I found a lot of different solutions on the internet that contradict each other.

To simplify my question, I'll use an example. Let's say I want to generate a map for a 2D game using the MVC design pattern:

MapView.java

public class MapView extends TheViewComponent {
    public MapView() {
        // Create the view
    }
}

MapController.java

public class MapController {
    // …

    public MapController(Map map, MapView mapView) {
        this.map = map;
        this.mapView = mapView;
    }
}

Map.java

public class Map {
    public void generate() {
        // Should create tiles in my MapView.
    }
}

Main.java

public class Main {
    public Main() {
        Map map = new Map();
        MapView mapView = new MapView();
        MapController mapController = new MapController(map, mapView);
    }
}

In the generate() method (Map.java), I don't understand how I can to update the view. In my Map class I don't have the reference to the controller or the view.

• Should I pass the view to the model with new Map(mapView) ? (seems weird…)
• Should I generate the map in the Controller? But if that's true, let's say if I have a list of tiles in my Map.java , and let's say for the example that I have operations to do on Tile and TileView (like my map). I want to store an ArrayList<Tile> and not an ArrayList<TileController> … So this second solution seems weird too…

Answer 1

The domain model Map should only hold the structure of the map and should make it accessible by the outer world (eg getTiles() ). Then, the view should use that domain data to render a map accordingly.

For manipulation, the controller should provide entry points for the relevent actions and dispatch them to a service layer that in turn does update the domain model.

Answer 2

MVC is an architectural pattern with the goal to separate responsibilities

Model
This is your business layer (domain and logic) and should not have any say on how you are going to "view" the data. For example the Model provides you an object/list/map with the information to be displayed.

Tip: here your code should not rely on web frameworks or HTTP Servlet API

View
This is the layer responsible to render the data in the User Interface: it should not include business rules or security, but only presentation logic

Controller
It sits in the middle: it dispatches the request to the relevant Model and forward the outcome to the appropriate View