无法使JComboBox更新JFrame

时间:2016-03-03 20:57:37

标签: java swing jframe actionlistener jcombobox

真的很感激一点帮助。

问题

我们有一个幻想课,上面有一个组合框。从组合框中选择阵型时,框架会通过按钮进行更新。但是因为当我将动作监听器添加到组合框时,它只会让我在主要方法中创建我的类时在幻想类的构造函数中执行它,我必须将幻想类和小队类交给TeamController类所以在创建幻想类时,动作列表器不在组合框中,所以它不起作用。任何帮助都将受到高度赞赏。

主类

public class Main {

  public static void main(String[] args) {
    Fantasy f = new Fantasy();
    Squad s = new Squad();
    TeamController tc = new TeamController(f, s);
    TextController txC = new TextController(s);
    f.updateController(tc, txC);
    f.setVisible(true);
  }

}

幻想班

public class Fantasy extends JFrame {
  private JPanel goalPanel;
  private JPanel defendPanel;
  private JPanel midPanel;
  private JPanel attPanel;
  private JPanel bench;
  private JComboBox formation;
  private Button myButton;
  private TeamController control;
  private TextController tControl;
  private List < Button > buttons;

  public Fantasy() {
    super("Fantasy Football");
    buttons = new ArrayList < Button > ();
    createWidgets();
  }

  public void createWidgets() {
    JPanel formPanel = new JPanel(new GridLayout(1, 0));
    goalPanel = new JPanel(new FlowLayout());
    defendPanel = new JPanel(new FlowLayout());
    midPanel = new JPanel(new FlowLayout());
    attPanel = new JPanel(new FlowLayout());
    bench = new JPanel(new FlowLayout());

    JComboBox formation = new JComboBox();
    String[] addFormation = {
      "4 - 4 - 2", "4 - 3 - 3", "3 - 5 - 2", "5 - 3 - 2", "3 - 4 - 3", "4 - 5 - 1"
    };

    for (String newForm: addFormation) {
      formation.addItem(newForm);
    }

    formation.addActionListener(control);

    setLayout(new GridLayout(6, 0));
    add(formPanel);
    formPanel.add(formation);
    add(goalPanel);
    add(defendPanel);
    add(midPanel);
    add(attPanel);
    add(bench);

    pack();
    setDefaultCloseOperation(EXIT_ON_CLOSE);
  }

  public JComboBox getForm() {
    return formation;
  }

  public JPanel getGoal() {
    return goalPanel;
  }

  public JPanel getDef() {
    return defendPanel;
  }

  public JPanel getMid() {
    return midPanel;
  }

  public JPanel getAtt() {
    return attPanel;
  }

  public JPanel getBench() {
    return bench;
  }

  public void createDefender(String text, String ID) {
    addButtons(text, ID, defendPanel);
  }

  public void createMid(String text, String ID) {
    addButtons(text, ID, midPanel);
  }

  public void createAtt(String text, String ID) {
    addButtons(text, ID, attPanel);
  }

  public void addButtons(String text, String ID, JPanel panel) {
    myButton = new Button(text, ID);
    myButton.getButton().addActionListener(control);
    myButton.getText().addTextListener(tControl);
    buttons.add(myButton);
    panel.add(myButton);
  }

  public void updateController(TeamController control, TextController tControl) {
    this.control = control;
    this.tControl = tControl;
  }

  public List < Button > getButtons() {
    return buttons;
  }

}

ActionListner - TeamController类

public class TeamController implements ActionListener {
  private Fantasy fantasy;
  private Squad squad;
  private JComboBox form;
  private ArrayList < Button > button;

  public TeamController(Fantasy fantasy, Squad squad) {
    this.fantasy = fantasy;
    this.form = fantasy.getForm();
    this.button = (ArrayList < Button > ) fantasy.getButtons();
    this.squad = squad;
  }


  public void actionPerformed(ActionEvent e) {
    if (e.getSource() == form) {
      comboChooser((JComboBox) e.getSource());
    } else {
      fileChooser((Button) e.getSource());
    }
  }

  public void comboChooser(JComboBox form) {
    //restart the pane
    fantasy.getContentPane().removeAll();
    fantasy.createWidgets();
    //add the goalie buttons and labels in
    fantasy.addButtons("GoalKeeper", squad.getAllGoal().get(0).getID(), fantasy.getGoal());
    //2. break it up into each def mid att
    //JComboBox format = form;
    String[] split = ((String) form.getSelectedItem()).split("-");
    int[] splits = new int[3];
    for (int i = 0; i < split.length; i++) {
      splits[i] = Integer.parseInt(split[i].trim());
    }
    //3. create number of widgets for each posit in each panel
    //4. add leftover to bench

    makeDefender(splits[0], squad.getAllDef());
    makeMid(splits[1], squad.getAllMid());
    makeAttack(splits[2], squad.getAllAtt());

    fantasy.pack();
  }

  public void fileChooser(Button button) {
    final JFileChooser fileChooser = new JFileChooser("C:\\Users\\Michael\\Documents\\Java WorkSpace\\ExerciseThree\\Minor Piece of Coursework 3 Resources\\squad");
    int getVal = fileChooser.showOpenDialog(button.getButton());
    if (getVal == JFileChooser.APPROVE_OPTION) {
      File file = fileChooser.getSelectedFile();
      button.getButton().setVisible(false);
      button.add(button.updateButton(file), BorderLayout.CENTER);
      Player selectedPlayer = squad.getByID(button.getName());
      selectedPlayer.setPath(file.getPath());
      String playerName = file.getName();
      if (playerName.endsWith(".jpg")) {
        playerName.substring(0, playerName.length() - 4);
        selectedPlayer.setName(playerName);
      }
      button.getText().setText(playerName);
    } else {
      System.out.println("Cancelled your choice");
    }

  }

  public void makeDefender(int number, List < Defender > list) {
    for (int i = 0; i < number; i++) {
      String ID = list.get(i).getID();
      fantasy.createDefender("Defender", ID);
    }
  }

  public void makeMid(int number, List < Midfielder > list) {
    for (int i = 0; i < number; i++) {
      String ID = list.get(i).getID();
      fantasy.createMid("Midfielder", ID);
    }
  }

  public void makeAttack(int number, List < Striker > list) {
    for (int i = 0; i < number; i++) {
      String ID = list.get(i).getID();
      fantasy.createAtt("Striker", ID);
    }
  }

  public void updateSquad(Squad squad) {
    this.squad = squad;
  }
}

1 个答案:

答案 0 :(得分:3)

因此,您问题的基本答案是使用Observer Pattern,控制器可以观察视图所做的更改,并且(可能)通知模型。

Swing已经是MVC的一种形式(al-a M-VC),因此尝试在其上实现另一个MVC会让你头疼。

相反,退后一步。控制器不关心事情是如何完成的,它只关心它在完成时得到通知,因此实际上并不需要知道视图是如何实现的,只是它符合已知的合同(它变成黑盒子)。

视图反过来不关心控制器或模型

通过这种方式,您可以以任何您想要的方式实现视图,并且无需更改控制器以适应它,只要您支持由两者定义的联系人

当我做这样的事情时,我总是从接口开始,这使我能够专注于需求而不用担心细节,“我希望你这样做”,而不关心“你如何完成它” ...

public interface FantasyView {

    public String getFormation();
    public void setFormation(String formation); // Maybe throw an IllegalArgumentException or use an object or enum

    // Other information which the might be useful to return
    public void addFormationChangedObserver(ChangeListener listener);
    public void removeFormationChangedObserver(ChangeListener listener);

    public JComponent getView();

}

public interface SquadModel {
    // Some getters and setters
    // Some observers so the controller and get notified by changes and
    // update the view accordingly...
}

public interface TeamController {
    public FantasyView getView();
    public SquadModel getModel();
}

正如您所看到的,FantasyView通过ChangeListener(我很懒,所以我重新使用可用的代码)提供了对形成变化的观察者,它没有说出如何产生,只有当地层发生变化时,它才会产生一个事件。

其他任何接口都没有实际实现ChangeListener,因此它本身并不是合同的要求,但如果你想知道地层何时发生变化,你需要提供一个。

现在,控制器的可能实现可能看起来像......

public class DefaultTeamController implements TeamController {

    private FantasyView view;
    private SquadModel model;

    public DefaultTeamController(FantasyView view, SquadModel model) {
        this.view = view;
        this.model = model;

        view.addFormationChangedObserver(new ChangeListener() {
            @Override
            public void stateChanged(ChangeEvent e) {
                SquadModel model = getModel();
                // update model accordingly
            }
        });

        // Add observers to model...
    }

    @Override
    public FantasyView getView() {
        return view;
    }

    @Override
    public SquadModel getModel() {
        return model;
    }

}

控制器是否已暴露在视图中?不,它只是向视图注册ChangeListener的实例。视图永远不应该假设ChangeListener的实现是什么,只应该与接口的合同进行交互

现在,您可能想知道如何从ActionListener转到ChangeListener ....

JComboBox formation = new JComboBox();
//...
formation.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        fireFormationChanged();
    }
});

//...

protected void fireFormationChanged() {
    // changeListeners is a simple List of ChangeListener
    // this is instance of FantasyView
    ChangeEvent evt = new ChangeEvent(this);
    for (ChangeListener listener : changeListeners) {
        listener.stateChanged(evt);
    }
}

作为例子