Question

我得到的主要问题是无法在静态函数sendReceivedata中设置标签... netbeans为所有jcomponents生成的代码是私有的我无法修改它们并且如果我在构造函数中调用sendReceivedata函数然后程序将执行但不显示gui

主要问题：无法在静态功能中设置标签

public class Server extends javax.swing.JFrame {

    static public Socket socket;

    public static void sendReceivedata()
    {
        try
        {
            ServerSocket serverSocket=new ServerSocket(8181);
            jLabel2.setText("Server is waiting for Connection");
            while(true)
            {
                //waiting for connection
                socket = serverSocket.accept();
                jLabel3.setText("Connected");
                //ready for reading message from client
                System.out.println("Connected");
                BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));

                String receivemsg=br.readLine();
                String receivemsg1=br.readLine();

                jLabel4.setText("Data Receive From Client is ");
                jLabel5.setText(receivemsg);
                jLabel6.setText(receivemsg1);
            }
        }
        catch(Exception e)
        {
            System.out.println("ab "+e);
        }
    }

    public Server()
    {
        super("Server Side");
        initComponents();
    }

    public static void main(String args[])
    {
        //</editor-fold>
        java.awt.EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                new Server().setVisible(true);      
            }
        });
        sendReceivedata();
    }

    // Variables declaration - do not modify                     
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JLabel jLabel5;
    private javax.swing.JLabel jLabel6;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTable jTable1;
    // End of variables declaration                   
}

Answer 1

问题是sendReceivedata()未使用事件调度程序线程（EDT）上下文执行，该上下文是负责更新图形的线程因此，您执行的任何UI操作都不会显示。

要解决此问题，您需要使用SwingUtilities.invokeLater(Runnable run)。因为，在你的情况下，你正在更新多个标签，我建议你为每个标签都有一个方法，如下所示：

private static updateJLabel2(final String text) {
    final JLabel l = jLabel2;
    SwingUtilities.invokeLater(new Runnable() {
        @Override
        public void run() {
            l.setText(text);
        }
    }
}

并称之为：

try {
ServerSocket serverSocket=new ServerSocket(8181);
updateJLabel2("Server is waiting for Connection");
...

作为附注，请为您的标签提供更多相关名称。

另外请注意，请不要在sendReceivedata();之后放置new Server().setVisible(true);。虽然这样做应与我的答案具有相同的影响，但你也会在UI线程上进行非UI操作，这会导致你的界面冻结。

无法在函数sendReceivedata中的jlabels中设置文本

1 个答案: