從Java中的另一個線程更新JTextField

Question

我正在制作一個游戲客戶端/服務器，我正在新的線程更新客戶端GUI上的一些信息（使用Swing）。 我正在嘗試使用SwingUtilities但它不起作用。 另外，我聽說SwingUtilities每次使用它都會創建一個新線程，所以我也在尋找一種新方法（我有10個左右的JTextFields要更新）。 有沒有辦法在不使用SwingUtilities的情況下完成？ 這就是我現在所擁有的。

SwingUtilities.invokeLater(    
        new Runnable() {    
           public void run()    
           {    
              Client.status.setText("status = "+status); 
           }    
        });

Answer 1

有趣的是，就在最近我遇到了類似的問題，所以為了克服這個問題，我使用了SwingUtilities.invokeAndWait（Runnable runnable） ，這就是我創建的SSCCE按預期工作的原因，但是如果我將所有調用都改為invokeAndWait（）使用invokeLater（） ，可以清楚地看到這兩件事之間的區別。

Java Doc的一句話說：

Causes doRun.run() to be executed synchronously on the AWT event dispatching thread. 
This call blocks until all pending AWT events have been processed and 
(then) doRun.run() returns. This method should be used when an application thread 
needs to update the GUI.

這是我作為SSCCE表示冒泡排序動畫的一個小程序：

import javax.swing.*;

public class BubbleSortFrame extends JFrame
{
    private BubbleSortView contentPane;

    private void displayGUI()
    {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        contentPane = new BubbleSortView();
        setContentPane(contentPane);
        pack();
        setLocationByPlatform(true);
        setVisible(true);
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            @Override
            public void run()
            {
                new BubbleSortFrame().displayGUI();
            }
        });
    }
}

---

import java.awt.*;
import java.awt.event.*;
import java.lang.reflect.InvocationTargetException;
import javax.swing.*;

public class BubbleSortView extends JPanel
{
    private JLabel sizeLabel;
    private JTextField sizeField;
    private JTextField[] vField;
    private JLabel[] vLabel;
    private JButton startButton, createButton;
    private int size;
    private JPanel createPanel, animationPanel;

    private BubbleSort bubbleSort;

    public BubbleSortView()
    {
        size = 5;
        displayAndCreateGUI();
    }

    private void displayAndCreateGUI()
    {
        setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
        setOpaque(true);
        setBackground(Color.WHITE);
        JPanel basePanel = new JPanel();
        basePanel.setLayout(new GridLayout(2, 1, 5, 5));
        basePanel.setOpaque(true);
        basePanel.setBackground(Color.WHITE);

        JPanel topPanel = new JPanel();
        topPanel.setOpaque(true);
        topPanel.setBackground(Color.WHITE);
        topPanel.setBorder(
            BorderFactory.createTitledBorder("Input : "));
        topPanel.setLayout(new GridLayout(2, 1, 5, 5)); 
        /*
         * This will act as the area
         * for taking the input for
         * number of elements in an Array.
         */
        JPanel sizePanel = new JPanel();
        sizePanel.setOpaque(true);
        sizePanel.setBackground(Color.WHITE);
        sizeLabel = new JLabel("Enter Number of Elements : ");
        sizeField = new JTextField(10);
        createButton = new JButton("CREATE");

        /*
         * This will act as the area
         * where we will specify the values
         * for each index in an Array.
         */
        createPanel = new JPanel();
        createPanel.setOpaque(true);
        createPanel.setBackground(Color.WHITE);
        createPanel.setBorder(
            BorderFactory.createTitledBorder("Please Enter values for an Array : "));
        createPanel.setVisible(false);      

        animationPanel = new JPanel();
        animationPanel.setOpaque(true);
        animationPanel.setBackground(Color.WHITE);
        animationPanel.setBorder(
            BorderFactory.createTitledBorder("Animation : "));
        animationPanel.setVisible(false);   

        createButton.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent ae)
            {
                if (sizeField.getDocument().getLength() > 0)
                {
                    size = Integer.parseInt(sizeField.getText());
                    vField = new JTextField[size];
                    createPanel.setVisible(true);
                    for (int i = 0; i < size; i++)
                    {
                        vField[i] = new JTextField(5);
                        /*
                         * Adding the Listener to the
                         * last JTextField on the Right 
                         * Side.
                         */
                        if (i == (size - 1)) 
                        {
                            vField[i].addActionListener(new ActionListener()
                            {
                                @Override
                                public void actionPerformed(ActionEvent ae)
                                {
                                    animationPanel.setLayout(
                                            new GridLayout(1, size, 2, 2));
                                    animationPanel.setVisible(true);
                                    vLabel = new JLabel[size];
                                    for (int i = 0; i < size; i++)
                                    {
                                        vLabel[i] = new JLabel(
                                            vField[i].getText(), JLabel.CENTER);
                                        vLabel[i].setOpaque(true);
                                        vLabel[i].setBackground(Color.YELLOW);
                                        vLabel[i].setForeground(Color.RED);
                                        animationPanel.add(vLabel[i]);
                                    }
                                    animationPanel.revalidate();
                                    animationPanel.repaint();
                                    bubbleSort = new BubbleSort(vLabel, size);
                                    Thread t = new Thread(bubbleSort);
                                    t.start();
                                }
                            });
                        }
                        createPanel.add(vField[i]);
                    }
                    createPanel.revalidate();
                    createPanel.repaint();
                    createButton.setEnabled(false);
                }
                else
                    size = 5;
            }
        });
        sizePanel.add(sizeLabel);
        sizePanel.add(sizeField);
        sizePanel.add(createButton);

        /*
         * Initializing JTextField Array
         * so that it can be first presented
         * to the USER to take input for
         * 5 values.
         */
        //for (int i = 0; i < size; i++)
        //  vField[i] = new JTextField(5);
        topPanel.add(sizePanel);
        topPanel.add(createPanel);
        basePanel.add(topPanel);
        basePanel.add(animationPanel);
        add(basePanel);
    }

    private class BubbleSort implements Runnable
    {
        private int[] arr;
        private JLabel[] vLabel;
        private int size;
        private int pass;

        public BubbleSort(JLabel[] label, int size)
        {
            vLabel = label;
            this.size = size;
            pass = 1;
            for (int i = 0; i < size; i++)
                System.out.print("" + vLabel[i].getText() + "\t");
            System.out.println("");
        }

        @Override
        public void run()
        {
            try
            {
                bubbleSorting();
            }
            catch (InvocationTargetException ite)
            {
                ite.printStackTrace();
            }
            catch(InterruptedException ie)
            {
                ie.printStackTrace();
            }
        }

        private void bubbleSorting() 
            throws InterruptedException, InvocationTargetException
        {
            while (pass < size)
            {
                for (int i = 0; i < (size - pass); i++)
                {
                    final int j = i;
                    SwingUtilities.invokeAndWait(new Runnable()
                    {
                        @Override
                        public void run()
                        {
                            vLabel[j].setBackground(Color.RED);
                            vLabel[j].setForeground(Color.WHITE);
                            vLabel[j + 1].setBackground(Color.RED);
                            vLabel[j + 1].setForeground(Color.WHITE);
                        }
                    });
                    try
                    {
                        Thread.sleep(1500);
                    }
                    catch(InterruptedException ie)
                    {
                        ie.printStackTrace();
                    }
                    int left = Integer.parseInt(vLabel[i].getText());
                    int right = Integer.parseInt(vLabel[i + 1].getText());
                    if (left > right)
                    {
                        String temp = vLabel[i].getText();
                        vLabel[i].setText(vLabel[i + 1].getText());
                        vLabel[i + 1].setText(temp);
                    }
                    SwingUtilities.invokeAndWait(new Runnable()
                    {
                        @Override
                        public void run()
                        {
                            vLabel[j].setBackground(Color.YELLOW);
                            vLabel[j].setForeground(Color.RED);
                            vLabel[j + 1].setBackground(Color.YELLOW);
                            vLabel[j + 1].setForeground(Color.RED);
                        }
                    });
                }
                System.out.println("Pass : " + pass + "\tSize : " + size);  
                SwingUtilities.invokeAndWait(new Runnable()
                {
                    @Override
                    public void run()
                    {
                        vLabel[size - pass].setBackground(Color.GREEN);
                        vLabel[size - pass].setForeground(Color.BLUE);
                    }
                });
                pass++;
            }
            SwingUtilities.invokeAndWait(new Runnable()
            {
                @Override
                public void run()
                {
                    vLabel[0].setBackground(Color.GREEN);
                    vLabel[0].setForeground(Color.BLUE);
                }
            });
        }
    }
}

Answer 2

我不知道你從哪里聽說過“ SwingUtilities創建一個新主題 ”，但我認為你已經誤解或被錯誤地告知了。 SwingUtilities.invokeLater將Runnable放在Event Dispatcher隊列的末尾。 然后隊列在它自己的線程上下文（及時）內處理此事件，調用Run ，沒有為此進程創建“新”線程。

至於你的問題。

您可能需要在字段父容器上調用validate() （可能還有repaint() ）以鼓勵它更新;）

不，沒有任何其他方法可以跨線程同步UI，這就是SwingUtilities的原因