怎么能做到不重复内部框架

Question

我正在测试一些使用internal frame的代码。所以我不想打开已经在我的程序中运行的新internal frame。我的意思是，当我单击菜单以打开outerframe中已经打开的某些internal frame时，该内部框架可能会在我的框架中重复，我该如何解决这种情况。请。

Answer 1

这是一个非常简单的例子，希望对您有所帮助。

我扩展了一个 JInternalFrame

import javax.swing.JInternalFrame;
public class WeatherIFrame extends JInternalFrame {
    public WeatherIFrame() {
        this.setTitle("Weather");
        this.setSize(300, 200);
        this.setVisible(true);
        this.setClosable(true);
        this.setResizable(true);        
    }
}

一个类，它生成 JFrame 并包含 JDesktopPane

import de.professional_webworkx.dashboard.internalframes.WeatherIFrame;
import java.awt.Menu;
import java.awt.MenuBar;
import java.awt.MenuItem;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JDesktopPane;
import javax.swing.JFrame;
import javax.swing.event.InternalFrameAdapter;
import javax.swing.event.InternalFrameEvent;
import javax.swing.event.InternalFrameListener;
public class MainFrame extends JFrame {
    private JDesktopPane desktopPane;
    private WeatherIFrame weatherIFrame;
    /**
     * Menuitems
     */
    MenuItem openWeatherFrame;
    MenuItem exitApp;
    public MainFrame() {            
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setTitle("Dashboad");
        this.setSize(1024, 768);
        this.getContentPane().add(initDesktopPane());
        this.setMenuBar(initMenu());
        this.setVisible(true);
    }
    private JDesktopPane initDesktopPane() {
        desktopPane = new JDesktopPane();
        return desktopPane;
    }
    private MenuBar initMenu() {
        MenuBar menuBar = new MenuBar();
        Menu fileMenu = new Menu("File");
        openWeatherFrame = new MenuItem("Show Weatherforcast");
        openWeatherFrame.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if(weatherIFrame == null) {
                    weatherIFrame = new WeatherIFrame();
                    weatherIFrame.addInternalFrameListener(new InternalFrameListener() {
                        @Override
                        public void internalFrameOpened(InternalFrameEvent e) {
                        }
                        @Override
                        public void internalFrameClosing(InternalFrameEvent e) {
                        }
                        @Override
                        public void internalFrameClosed(InternalFrameEvent e) {
                            weatherIFrame = null;
                        }
                        @Override
                        public void internalFrameIconified(InternalFrameEvent e) {
                        }
                        @Override
                        public void internalFrameDeiconified(InternalFrameEvent e) {
                        }
                        @Override
                        public void internalFrameActivated(InternalFrameEvent e) {
                        }
                        @Override
                        public void internalFrameDeactivated(InternalFrameEvent e) {
                        }
                    });
                    desktopPane.add(weatherIFrame);
                }
            }
        });            
        fileMenu.add(openWeatherFrame);
        menuBar.add(fileMenu);
        return menuBar;
    }
}

现在，运行它。

import de.professional_webworkx.dashboard.frame.MainFrame;
import javax.swing.SwingUtilities;
public class Dashboard {
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new MainFrame();
            }
        });
    }    
}