2

我正在尝试使用 MVC 架构模式构建一个简单的 Java Swing 应用程序。我所做的是在我的视图中创建用户界面组件（作为私有），并具有返回组件的公共方法。然后这些方法被控制器调用，通过它我可以为事件/动作监听器编写方法。下面是一个示例：

看法：

private JButton btnAdd;

    public JButton getBtnAdd(){
        return btnAdd;
    }

控制：

myGuiFrame gui = new myGuiFrame();


        //on add button clicked
    gui.getBtnAdd().addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            //calls to model
        }
    });

这个实现正确吗？

如果是这样，那么我对 FocusListeners 有问题。当我在视图中创建 FocusListener 时，会在视图中创建 focusLost 和 focusGained 方法。

private FocusListener l;

someComponent.addFocusListener(l);

        l = new FocusListener() {

            @Override
            public void focusLost(FocusEvent e) {
                // TODO Auto-generated method stub
            }

            @Override
            public void focusGained(FocusEvent e) {
                // TODO Auto-generated method stub

            }
        };

我希望所有事件处理程序都在我的控制器中。我的问题是......有没有一种方法可以从我的控制器调用/声明 focusLost 和 focusGained 方法？我试图将 FocusListener 定义为 public，以便我可以在我的控制器中定义它：

看法：

public FocusListener l;
public someComponentType someComponent;

控制器：

gui.l = new FocusListener() {
    @Override
    public void focusLost(FocusEvent e) {
        // TODO Auto-generated method stub

}

@Override
public void focusGained(FocusEvent e) {
    // TODO Auto-generated method stub
    gui.someComponent.addFocusListener(gui.l);

    }

};

然而，这不起作用。

是否可以从控制器处理 FocusEvents？

编辑：

天哪，我的坏。不太明白罗宾的意思。我太专注于在某处明确定义 FocusListener。一个简单的：

    gui.getTextFieldEmployeeCode().addFocusListener(new FocusListener() {

        @Override
        public void focusLost(FocusEvent e) {
            // TODO Auto-generated method stub

        }

        @Override
        public void focusGained(FocusEvent e) {
            // TODO Auto-generated method stub
            System.out.println("YES!!!");
        }
    });

在控制器中可以按照我计划的方式正常工作，尽管我非常喜欢 nIcE cOw 的处理方式。只是出于好奇，是否有在 Swing 应用程序上实现 MVC 的标准或广泛接受的方式？

4

1 回答 1

5

据我了解，您的做法是这样的。更好的是，我更喜欢匿名类，它们尊重封装的概念。在这里尝试一下这段代码，看看你能掌握什么：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class View
{
    private JButton focusButton;
    private JButton spareButton;

    private void createAndDisplayGUI()
    {
        JFrame frame = new JFrame("VIEW");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        JPanel contentPane = new JPanel();
        contentPane.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5));

        focusButton = new JButton("GAINED/LOST");
        focusButton.addFocusListener(new ButtonController(this));

        spareButton = new JButton("SPARE");
        spareButton.setOpaque(true);
        spareButton.addActionListener(new ButtonController(this));
        spareButton.addFocusListener(new ButtonController(this));

        contentPane.add(focusButton);
        contentPane.add(spareButton);

        frame.setContentPane(contentPane);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    public JButton getFocusButton()
    {
        return focusButton;
    }

    public JButton getSpareButton() 
    {
        return spareButton;
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new View().createAndDisplayGUI();
            }
        });
    }
}

class ButtonController implements FocusListener, ActionListener
{
    private View view;
    private JButton focusButton;
    private JButton spareButton;

    public ButtonController(View v)
    {
        view = v;
        focusButton = view.getFocusButton();
        spareButton = view.getSpareButton();
    }

    public void actionPerformed(ActionEvent ae)
    {
        JButton button = (JButton) ae.getSource();

        if (button == spareButton)
        {
            spareButton.setBackground(Color.BLUE);
            focusButton.setEnabled(true);
        }
    }

    public void focusGained(FocusEvent fe)
    {
        JButton button = (JButton) fe.getSource();

        if (button == focusButton)
        {
            focusButton.setEnabled(true);
        }
        else if (button == spareButton)
        {
            spareButton.setBackground(Color.WHITE);
        }
    }

    public void focusLost(FocusEvent fe)
    {
        JButton button = (JButton) fe.getSource();

        if (button == focusButton)
        {
            focusButton.setEnabled(false);
        }
        else if (button == spareButton)
        {
            spareButton.setBackground(Color.DARK_GRAY.darker());
        }
    }
}

另一种方法是，如果您对getters/setters发送引用感到恼火，请按如下方式定义一个内部类（上一个示例的简单解决方法）：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class View
{
    private JButton focusButton;
    private JButton spareButton;

    private void createAndDisplayGUI()
    {
        JFrame frame = new JFrame("VIEW");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        JPanel contentPane = new JPanel();
        contentPane.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5));

        focusButton = new JButton("GAINED/LOST");
        focusButton.addFocusListener(new ButtonController());

        spareButton = new JButton("SPARE");
        spareButton.setOpaque(true);
        spareButton.addActionListener(new ButtonController());
        spareButton.addFocusListener(new ButtonController());

        contentPane.add(focusButton);
        contentPane.add(spareButton);

        frame.setContentPane(contentPane);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    private class ButtonController implements FocusListener, ActionListener
    {

        public void actionPerformed(ActionEvent ae)
        {
            JButton button = (JButton) ae.getSource();

            if (button == spareButton)
            {
                spareButton.setBackground(Color.BLUE);
                focusButton.setEnabled(true);
            }
        }

        public void focusGained(FocusEvent fe)
        {
            JButton button = (JButton) fe.getSource();

            if (button == focusButton)
                focusButton.setEnabled(true);
            else if (button == spareButton)
                spareButton.setBackground(Color.WHITE);
        }

        public void focusLost(FocusEvent fe)
        {
            JButton button = (JButton) fe.getSource();

            if (button == focusButton)
                focusButton.setEnabled(false);
            else if (button == spareButton)
                spareButton.setBackground(Color.DARK_GRAY.darker());
        }
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new View().createAndDisplayGUI();
            }
        });
    }
}
于 2012-04-20T13:11:39.500 回答