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您好大师，我是一名初学者 Java swing 开发人员，正在尝试构建一个简单的应用程序......这是一个简化版本。

设置：1 个 JFrame，2 个基于 BorderLayout 的选项卡式面板（A 和 B），每个都有 1 个文本文件，共享 JPanel 类，组合框和 ItemListener 在每个选项卡（北）中初始化

问题：如何根据文本来自哪个面板来控制对文本字段文本的更新，例如。如果我在 TabA 中选择 Apples，Item Listener 也会更新 TabB 上的 TextField。我想要完成的是确定调用来自 TabA 或 TabB 的位置，并且只更新与该选项卡关联的文本字段。

希望这有点道理

public class Main extends JFrame {

    private static final long serialVersionUID = 1L;
    private JPanel contentPane;
    public JTextField tfPanelA;
    public JTextField tfPanelB;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Main frame = new Main();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public Main() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        contentPane.setLayout(new BorderLayout(0, 0));
        setContentPane(contentPane);            
        JTabbedPane tabbedPane = new JTabbedPane(JTabbedPane.TOP);
        contentPane.add(tabbedPane, BorderLayout.CENTER);           
        JPanel panelA = new JPanel();
        tabbedPane.addTab("Tab A", null, panelA, null);
        panelA.setLayout(new BorderLayout(0, 0));           
        sharedPanel s1 = new sharedPanel(this);
        panelA.add(s1, BorderLayout.NORTH);         
        tfPanelA = new JTextField();
        panelA.add(tfPanelA);
        tfPanelA.setColumns(10);            
        JPanel panelB = new JPanel();
        tabbedPane.addTab("Tab B", null, panelB, null);
        panelB.setLayout(new BorderLayout(0, 0));           
        sharedPanel s2 = new sharedPanel(this);
        panelB.add(s2, BorderLayout.NORTH);
        tfPanelB = new JTextField();
        panelB.add(tfPanelB);
        tfPanelB.setColumns(10);
    }    
}

// 共享类...

    public class sharedPanel extends JPanel {

    private Main app;
    private String[] clist = {"Apples","Oranges","Bananas"};
    /**
     * Create the panel.
     */
    public sharedPanel(final Main app) {
        this.app=app;
        setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));         
        JComboBox<String> comboBox = new JComboBox<String>();
        comboBox.setModel(new DefaultComboBoxModel<String>(clist));         
        comboBox.addItemListener(new ItemListener() {
            public void itemStateChanged(ItemEvent e) {
             //update PanelA's textfield ONLY if called from PanelA
             // do this if called from PanelA
                app.tfPanelA.setText(e.getItem().toString());   
             // do this if called from PanelB
                app.tfPanelB.setText(e.getItem().toString());
            }
        });         
        add(comboBox);    
    }    
}
4

2 回答 2

1

由于您有两个实例，因此您SharedPanel可以添加要更新的文本字段作为对构造函数的引用：

SharedPanel s1 = new SharedPanel(this, tfPanelA);

和

public SharedPanel(final Main app, final JTextField tf) {
    ...
    comboBox.addItemListener(new ItemListener() {
        public void itemStateChanged(ItemEvent e) {
            tf.setText(e.getItem().toString());
        }
    });
    ...
}
于 2013-07-24T04:56:41.770 回答
1

由于您sharedPanel为每个选项卡创建了一个新实例，只需提供对要更新的文本字段的引用...

你最终得到的东西更像......

public class sharedPanel extends JPanel {

    private JTextField field;
    private String[] clist = {"Apples","Oranges","Bananas"};
    public sharedPanel(final JTextField field) {
        this.field=field;
        setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));

        JComboBox<String> comboBox = new JComboBox<String>();
        comboBox.setModel(new DefaultComboBoxModel<String>(clist));

        comboBox.addItemListener(new ItemListener() {
            public void itemStateChanged(ItemEvent e) {
                sharedPanel.this.field.setText(e.getItem().toString());   
            }
        });

        add(comboBox);

    }

}

更新了“模型”示例

这是一个非常基本的示例，它只是一种可能使用模型来桥接公共面板和其他面板之间的变化的例子。这意味着公共面板不关心其他任何事情并更新提供的模型，这会向可以根据需要采取适当行动的相关方触发事件。

在此处输入图像描述在此处输入图像描述

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class TabbedModel {

    protected static final String[] MAIN_LIST = {"Apples","Oranges","Bananas"};

    public static void main(String[] args) {
        new TabbedModel();
    }

    public TabbedModel() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JTabbedPane tabPane = new JTabbedPane();
                tabPane.addTab("A", new ATab());
                tabPane.addTab("B", new ATab());

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(tabPane);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class DefaultCommonModel implements CommonModel {

        private List<ChangeListener> listeners;
        private String value;

        public DefaultCommonModel() {
            listeners = new ArrayList<>(25);
        }

        @Override
        public void addChangeListener(ChangeListener listener) {
            listeners.add(listener);
        }

        @Override
        public void removeChangeListener(ChangeListener listener) {
            listeners.remove(listener);
        }

        @Override
        public void setValue(String aValue) {
            if (aValue == null ? value != null : !aValue.equals(value)) {
                value = aValue;
                fireStateChanged();
            }
        }

        @Override
        public String getValue() {
            return value;
        }

        protected void fireStateChanged() {

            if (!listeners.isEmpty()) {
                ChangeEvent evt = new ChangeEvent(this);
                for (ChangeListener listener : listeners) {
                    listener.stateChanged(evt);
                }
            }

        }

    }

    public interface CommonModel {

        public void addChangeListener(ChangeListener listener);
        public void removeChangeListener(ChangeListener listener);

        public void setValue(String value);
        public String getValue();

    }

    public class CommonPanel extends JPanel {

        private CommonModel model;
        private JComboBox comboBox;

        public CommonPanel(CommonModel model) {
            this.model = model;
            setLayout(new GridBagLayout());
            comboBox = new JComboBox(new DefaultComboBoxModel<>(MAIN_LIST));
            comboBox.addItemListener(new ItemListener() {
                @Override
                public void itemStateChanged(ItemEvent e) {
                    String value = (String) e.getItem();
                    CommonPanel.this.model.setValue(value);
                }
            });
            add(comboBox);
        }

    }

    public class ATab extends JPanel {

        private List<JTextField> fields;

        public ATab() {
            setLayout(new GridBagLayout());
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridwidth = GridBagConstraints.REMAINDER;

            DefaultCommonModel model = new DefaultCommonModel();
            model.addChangeListener(new ChangeListener() {
                @Override
                public void stateChanged(ChangeEvent e) {
                    CommonModel model = (CommonModel) e.getSource();
                    for (JTextField field : fields) {
                        field.setText(model.getValue());
                    }
                }
            });
            CommonPanel commonPanel = new CommonPanel(model);

            add(commonPanel, gbc);

            fields = new ArrayList<>(25);
            for (int index = 0; index < random(); index++) {
                JTextField field = new JTextField(10);
                add(field, gbc);
                fields.add(field);
            }
        }

        protected int random() {

            return (int)Math.round(Math.random() * 9) + 1;

        }

    }

}
于 2013-07-24T04:57:03.753 回答