I've got a project based around the Model-View-Controller paradigm, and I've been having a lot of trouble with getting it to work properly.
The program has 4 panels, which are supposed to allow me to modify an oval drawn on the screen in various ways. These seem to work fine, and after considerable trouble I was able to get them to display in the JFrame which holds the whole shebang. I've managed to get them to display by breaking away from the provided instructions, but when I do that, I can't seem to get the oval to update. However, if I follow the directions to the letter, I only ever see an empty frame.
The project had pretty specific directions, which I followed up to a point, but some of the documentation was unclear. I think what I'm missing must be something simple, since nothing is jumping out at me as not making sense. I have to admit though that my Java experience is limited and my experience with GUI design/paradigms is even more so.
Anyway, I've been searching the web and this site extensively trying to figure out what's wrong, but this is a somewhat specific example and honestly I just don't know enough about this to generalize any of the answers I've found online and figure out what's missing. I've been poring over this code for far too long now so I'm really hoping someone can help me out.
public class Model {
private Controller controller;
private View view;
private MvcFrame mvcFrame;
private int radius = 44;
private Color color = Color.BLUE;
private boolean solid = true;
//bunch of mutators and accessors for the above variables
public Model() {
controller = new Controller(this);
view = new View(this);
mvcFrame = new MvcFrame(this);
}
}
Here's the model class. This seems to be fairly simple. I think my understanding of what's going on here is solid, and nothing seems to be wrong. Included mostly for context.
public class Controller extends JPanel{
private Model model;
public Controller(Model model) {
this.model = model;
setBorder(BorderFactory.createLineBorder(Color.GREEN));
setLayout(new GridLayout(4,1));
add(new RadiusPanel(model));
add(new ColorPanel(model));
add(new SolidPanel(model));
add(new TitlePanel(model));
}
}
This is the Controller class. As far as I can tell, the setBorder, setLayout, and series of adds do nothing here. I had them commented out, but this is the way that the instructions told me to do things, so either there's a mistake there or something about my setup is wrong. However, when I did it this way, I would get an empty window (JFrame) but none of the panels would show up in it. What I did to fix this is put those add functions in the mvcFrame class:
public class MvcFrame extends JFrame {
private Model model;
public MvcFrame(Model model){
this.model = model;
//setLayout(new GridLayout(4,1));
//add(new RadiusPanel(model));
//add(new ColorPanel(model));
//add(new SolidPanel(model));
//add(new TitlePanel(model));
//add(new View(model));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setSize(800,600);
setVisible(true);
}
}
So here's where things kind of started getting weird. The first block of commented out code is the same as what's in the Controller class. The reason I have it commented out is because that was just a lucky guess - it's not supposed to be like that according to the instructions. However, this did work for getting the panels to show up - but at that point I was still tearing my hair out trying to get the oval to display.
The other commented line ( add(new View(model)); ) was a different attempt at making things work. In this case, I put those add functions in the View class (see commented out code below). This actually worked to display both the oval and the panels, but that method wouldn't allow me to update the oval. Also, though I just had the oval displaying, I can't seem to figure out what exactly made that happen, and I can't seem to make it come back.
public class View extends JPanel{
private Model model;
public View(Model model) {
this.model = model;
//setLayout(new GridLayout(4,1));
//add(new RadiusPanel(model));
//add(new ColorPanel(model));
//add(new SolidPanel(model));
//add(new TitlePanel(model));
repaint();
}
@Override
protected void paintComponent(Graphics g){
super.paintComponent(g);
//center of view panel, in pixels:
int xCenter = getWidth()/2;
int yCenter = getHeight()/2;
int radius = model.getRadius();
int xStart = xCenter - radius;
int yStart = yCenter - radius;
int xWidth = 2 * radius;
int yHeight = 2 * radius;
g.setColor(model.getColor());
g.clearRect(0, 0, getWidth(), getHeight());
if (model.isSolid()){
g.fillOval(xStart, yStart, xWidth, yHeight);
} else {
g.drawOval(xStart, yStart, xWidth, yHeight);
}
}
}
Kinda same idea as before - the commented out code is stuff I added to try to get things working, but is not based on the provided directions. In the case where that stuff was uncommented, I had the add(new View(model)); line from the mvcFrame line uncommented as well.
The various panel classes (SolidPanel, ColorPanel, etc) simply extend a class called ControlPanel which extends JPanel. These all seem to work as expected, not having much issue with them. There is also a driver which launches the GUI. This also seems to work as expected.
The main problem I'm having is that I can't get the oval to show up, and the one time I could make it show up, none of the options for changing it seemed to work. I feel like I'm close but I'm just at a loss for other things to try out at this point.
Anyone who can help will have my sincerest gratitude.
