java - 在 Swing Java 中向 JList 添加元素

Question

我有一个在单击按钮时执行的函数。假设有一个循环将 1 加到 10 到 JList。我将该数据添加到 DefaultListModel。它完美地工作并且数字被添加。然后我在循环中添加了一个 Thread.sleep(1000)。但是输出是不同的。我想每秒添加 1 个元素。但现在它等待 10 秒，并在第 10 秒结束时将所有 1 加到 10。我哪里错了吗？

List processList = listNumbers.getSelectedValuesList();
DefaultListModel resultList = new DefaultListModel();
listResult.setModel(resultList);

for (int i = 0; i < processList.size(); i++) {
    resultList.addElement(String.valueOf(i));
    try {
        Thread.sleep(1000);
    }
    catch (InterruptedException ex) {
    }
}

Answer 1

不要使用，真的不要在EventDispashThread期间使用Thread.sleep(int)，因为 sleep 锁定了当前的Thread并且在本例 EventDispashThread，向 GUI 输出非预期的结果，更多信息在 Concurency in Swing 中，

如果你需要一些东西来延迟，然后将 Items wrappend 添加到 Runneble#Thread 中，将输出到 GUI 包装到 invokeLater 中，或者最好的方法是使用 javax.swing.Timer

编辑第一。示例如何使用 Thread.sleep(int) 以编程方式阻止 EDT，因为 othewise 不适用于期望输出到 GUI(代码非常冗长，因为我想编写代码)

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

public class ShakingButtonDemo implements Runnable {

    private JButton button;
    private JRadioButton radioWholeButton;
    private JRadioButton radioTextOnly;

    public static void main(String[] args) throws Exception {
        SwingUtilities.invokeLater(new ShakingButtonDemo());
    }

    @Override
    public void run() {
        radioWholeButton = new JRadioButton("The whole button");
        radioTextOnly = new JRadioButton("Button text only");
        radioWholeButton.setSelected(true);
        ButtonGroup bg = new ButtonGroup();
        bg.add(radioWholeButton);
        bg.add(radioTextOnly);
        button = new JButton("  Shake with this Button  ");
        button.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                shakeButton(radioWholeButton.isSelected());
            }
        });
        JPanel p1 = new JPanel();
        p1.setBorder(BorderFactory.createTitledBorder("Shake Options"));
        p1.setLayout(new GridLayout(0, 1));
        p1.add(radioWholeButton);
        p1.add(radioTextOnly);
        JPanel p2 = new JPanel();
        p2.setLayout(new GridLayout(0, 1));
        p2.add(button);
        JFrame frame = new JFrame();
        frame.setTitle("Shaking Button Demo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(p1, BorderLayout.NORTH);
        frame.add(p2, BorderLayout.SOUTH);
        frame.setSize(240, 160);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    private void shakeButton(final boolean shakeWholeButton) {
        final Point point = button.getLocation();
        final Insets margin = button.getMargin();
        final int delay = 75;
        Runnable r = new Runnable() {

            @Override
            public void run() {
                for (int i = 0; i < 30; i++) {
                    try {
                        if (shakeWholeButton) {
                            moveButton(new Point(point.x + 5, point.y));
                            Thread.sleep(delay);
                            moveButton(point);
                            Thread.sleep(delay);
                            moveButton(new Point(point.x - 5, point.y));
                            Thread.sleep(delay);
                            moveButton(point);
                            Thread.sleep(delay);
                        } else {// text only
                            setButtonMargin(new Insets(margin.top, margin.left + 3, margin.bottom, margin.right - 2));
                            Thread.sleep(delay);
                            setButtonMargin(margin);
                            Thread.sleep(delay);
                            setButtonMargin(new Insets(margin.top, margin.left - 2, margin.bottom, margin.right + 3));
                            Thread.sleep(delay);
                            setButtonMargin(margin);
                            Thread.sleep(delay);
                        }
                    } catch (InterruptedException ex) {
                        ex.printStackTrace();
                    }
                }
            }
        };
        Thread t = new Thread(r);
        t.start();
    }

    private void moveButton(final Point p) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                button.setLocation(p);
            }
        });
    }

    private void setButtonMargin(final Insets margin) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                button.setMargin(margin);
            }
        });
    }
}

编辑第二。与@camickr 的 kind hepl(看起来像 similair)

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

public class ShakeComponents1 {

    private JFrame frame = new JFrame();
    private final String items[] = {"One", "Two", "Three"};
    private Timer timer;
    private JPanel panel = new JPanel();
    private JPanel buttonPanel = new JPanel();
    private JButton button = new JButton("  Exit  ");
    private boolean repeats = true;
    private boolean runs = false;
    private Color clr[] = {Color.red, Color.blue, Color.magenta};
    private Insets initMargin;

    public static void main(String[] args) {

        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new ShakeComponents1().makeUI();
            }
        });
    }

    public void makeUI() {
        buttonPanel = new JPanel();
        buttonPanel.setBorder(new EmptyBorder(5, 5, 5, 5));
        buttonPanel.setLayout(new BorderLayout());
        button.setPreferredSize(new Dimension(100, 45));
        button.setForeground(Color.darkGray);
        button.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent event) {
                Runnable doRun = new Runnable() {

                    @Override
                    public void run() {
                        System.exit(0);
                    }
                };
                SwingUtilities.invokeLater(doRun);
            }
        });
        button.addMouseListener(new java.awt.event.MouseListener() {

            @Override
            public void mouseClicked(MouseEvent e) {
            }

            @Override
            public void mousePressed(MouseEvent e) {
            }

            @Override
            public void mouseReleased(MouseEvent e) {
            }

            @Override
            public void mouseEntered(MouseEvent e) {
                if (runs) {
                    SwingUtilities.invokeLater(new Runnable() {

                        @Override
                        public void run() {
                            runs = false;
                            timer.stop();
                            changePnlBorder(new EmptyBorder(5, 5, 5, 5));
                            changeBtnForegroung(Color.darkGray);
                        }
                    });
                }
            }

            @Override
            public void mouseExited(MouseEvent e) {
                if (!runs) {
                    timer.start();
                    runs = true;
                }
            }
        });
        buttonPanel.add(button);
        final Insets margin = button.getMargin();
        panel.add(buttonPanel);
        for (int i = 0; i < 2; i++) {
            JComboBox combo = new JComboBox(items);
            combo.setMinimumSize(new Dimension(50, 25));
            combo.setMaximumSize(new Dimension(150, 25));
            combo.setPreferredSize(new Dimension(100, 25));
            combo.addActionListener(new ShakeAction());
            panel.add(combo);
        }
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(panel);
        frame.pack();
        frame.setLocation(50, 50);
        frame.setVisible(true);
        timer = new Timer(500, new ShakeAction());
        timer.setRepeats(repeats);
        initMargin = button.getMargin();
    }

    private class ShakeAction extends AbstractAction {

        private static final long serialVersionUID = 1L;
        private int noColor = 0;
        private Border border;
        private int count = 0;

        @Override
        public void actionPerformed(ActionEvent e) {
            timer.start();
            if (count > 5) {
                new Thread(new Runnable() {

                    @Override
                    public void run() {
                        try {
                            Thread.sleep(750);
                            changeBtnForegroung(Color.darkGray);
                            Thread.sleep(750);
                            count = 0;
                            Thread.sleep(750);
                        } catch (Exception e) {
                            System.out.println(e);
                        }
                    }
                }).start();
            } else {
                new Thread(new Runnable() {

                    @Override
                    public void run() {
                        try {
                            runs = true;
                            if (noColor < 2) {
                                noColor++;
                                changeBtnForegroung(clr[noColor]);
                            } else {
                                noColor = 0;
                                changeBtnForegroung(clr[noColor]);
                            }
                            changeBtnMargin(new Insets(initMargin.top, initMargin.left + 10, initMargin.bottom, initMargin.right - 10));
                            border = new EmptyBorder(0, 5, 10, 5);
                            changePnlBorder(border);
                            Thread.sleep(100);
                            changeBtnMargin(new Insets(initMargin.top, initMargin.left - 10, initMargin.bottom, initMargin.right + 10));
                            border = new EmptyBorder(0, 0, 10, 10);
                            changePnlBorder(border);
                            Thread.sleep(100);
                            changeBtnMargin(new Insets(initMargin.top, initMargin.left + 10, initMargin.bottom, initMargin.right - 10));
                            border = new EmptyBorder(5, 10, 5, 0);
                            changePnlBorder(border);
                            Thread.sleep(100);
                            changeBtnMargin(new Insets(initMargin.top, initMargin.left - 10, initMargin.bottom, initMargin.right + 10));
                            border = new EmptyBorder(10, 10, 0, 0);
                            changePnlBorder(border);
                            Thread.sleep(100);
                            changeBtnMargin(new Insets(initMargin.top, initMargin.left, initMargin.bottom, initMargin.right));
                            border = new EmptyBorder(5, 5, 5, 5);
                            changePnlBorder(border);
                            Thread.sleep(100);
                            count++;
                        } catch (Exception e) {
                            System.out.println(e);
                        }
                    }
                }).start();
            }
        }
    }

    private void changePnlBorder(final Border b) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                buttonPanel.setBorder(b);
                buttonPanel.revalidate();
                buttonPanel.repaint();
            }
        });
    }

    private void changeBtnForegroung(final Color c) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                button.setForeground(c);
            }
        });
    }

    private void changeBtnMargin(final Insets margin) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                button.setMargin(margin);
            }
        });
    }
}

编辑第三。

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

public class DelayedComboBoxTest extends JFrame {

    private static final long serialVersionUID = 1L;
    private JCheckBox chkA = new JCheckBox("A");
    private JCheckBox chkB = new JCheckBox("B");
    private JCheckBox chkC = new JCheckBox("C");
    private JComboBox cboItems = new JComboBox();

    public DelayedComboBoxTest() {
        super("Delayed ComboBox Test");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        JPanel p = new JPanel();
        p.add(chkA);
        p.add(chkB);
        p.add(chkC);
        p.add(cboItems);
        Container c = getContentPane();
        c.setLayout(new BorderLayout());
        c.add(p);
        pack();
        cboItems.addPopupMenuListener(new MyPopupMenuListener());
    }

    private void rebuildList() {
        setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
        Vector<String> items = new Vector<String>();
        if (chkA.isSelected()) {
            items.add("A");
        }
        if (chkB.isSelected()) {
            items.add("B");
        }
        if (chkC.isSelected()) {
            items.add("C");
        }
        cboItems.setModel(new DefaultComboBoxModel(items));
        try {
            new Thread().sleep(2500); // simulate a long transaction
        } catch (InterruptedException ex) {
        }
        setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
    }

    public static void main(String[] args) {
        JFrame f = new DelayedComboBoxTest();
        f.setVisible(true);
    }

    private class MyPopupMenuListener implements PopupMenuListener {

        @Override
        public void popupMenuCanceled(PopupMenuEvent e) {
        }

        @Override
        public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
        }

        @Override
        public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
            int items = cboItems.getItemCount();
            rebuildList();

            if (items != cboItems.getItemCount()) {
                cboItems.hidePopup();
                cboItems.showPopup();
            }
        }
    }
}

但对于所有示例，必须存在 EDT 并且 EventQueue 中有 Events，否则简单不起作用