来自SwingWorker的jProgressBar更新

Question

我用来通过更新ProgressBar来监视长时间运行的任务.长时间运行的任务当然是在Swingworker线程中执行的.

我曾经编程过这样的事情:

public class MySwingWorkerClass extends SwingWorker<Void, Void> {   
    private JProgressBar progressBar;    

    public MySwingWorker(JProgressBar aProgressBar) {        
        this.progressBar = aProgressBar;           
        progressBar.setVisible(true);        
        progressBar.setStringPainted(true);
        progressBar.setValue(0);        
    }

    @Override
    public Void doInBackground() {
        //long running task
        loop {  
            calculation();
            progressBar.setValue(value);
        }
        return null;
    }    

    @Override
    public void done() {                
        progressBar.setValue(100);
        progressBar.setStringPainted(false);
        progressBar.setVisible(false);      
   }
}

但最近我发现我可以通过使用"setProgress"并定义属性更改并执行类似的操作来实现

public class MySwingWorkerClass extends SwingWorker<Void, Void> {   
    private JProgressBar progressBar;    

    public MySwingWorker(JProgressBar aProgressBar) {        
        addPropertyChangeListener(new PropertyChangeListener() {
            public void propertyChange(PropertyChangeEvent evt) {
                if ("progress".equals(evt.getPropertyName())) {
                    progressBar.setValue((Integer) evt.getNewValue());
                }
            }
        });

        progressBar.setVisible(true);        
        progressBar.setStringPainted(true);
        progressBar.setValue(0);
        setProgress(0);
    }

    @Override
    public Void doInBackground() {
        //long running task
        loop {  
            calculation();
            setProgress(value);
        }
        return null;
    }    

    @Override
    public void done() {                
        setProgress(100);
        progressBar.setValue(100);
        progressBar.setStringPainted(false);
        progressBar.setVisible(false);      
   }
}

我的问题是:我的第一个代码是可接受的,还是我应该使用setProgress进行任何调整？我发现第二个代码更复杂,在我的情况下,并不知道是否有任何优势或理由使用第二个.

有什么建议吗？

编辑 感谢您的回答.作为总结.第一种解决方案是"错误的",因为进度条更新是在EDT之外执行的.第二种解决方案是"正确的",因为进度条更新是在EDT内执行的

现在,根据@mKorbel的"有趣"答案,在我的情况下,我的计算结果是HTML文本,我"插入"(见此链接).我目前的代码如下.

我发布(字符串),我的流程代码就是这样

@Override
    protected void process(List<String> strings) {
        for (String s : strings) {
            try {
                htmlDoc.insertBeforeEnd(htmlDoc.getElement(htmlDoc.getDefaultRootElement(), StyleConstants.NameAttribute, HTML.Tag.TABLE), s);
            } catch (BadLocationException ex) {
            } catch (IOException ex) {
            }
        }
    }

在我的情况下,如何重复使用@mKobel来做同样的事情.我的意思是他在我的情况下使用覆盖表渲染我应该覆盖什么渲染器(jTextPane？)以及如何？

Answer 1

在第一个代码中,您在非EDT(事件调度程序线程)线程中调用以下行.所以它不是线程安全的:

progressBar.setValue(value);

这可能会导致意外行为,因为Swing未设计为线程安全库.

有不同的方法以Swing方式执行此操作.一个正确的方法就是你在第二篇文章中所做的.另一种publish()/process()方法是使用方法,第三种方法是编写自己的线程而不是SwingWorker使用SwingUtilities.invokeLater().

Answer 2

您的第二种方法是正确的，甚至记录在该类的类 javadoc 中SwingWorker。'progress' 事件在 EDT 上触发，因此您的侦听器会更新 EDT 上的进度条。您的第一种方法并非如此。

另一种方法的示例（如维齐尔所示使用）可以在我对之前的 SO 问题的回答publish/process中找到

Answer 3

我用来通过更新ProgressBar来监视长时间运行的任务.长时间运行的任务当然是在Swingworker线程中执行的.

对,你可以SwingWorker在所有情况下使用重定向任何繁重和长期运行的任务到Background

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

public class TableCellProgressBar {

    private String[] columnNames = {"String", "ProgressBar"};
    private Object[][] data = {{"dummy", 100}};
    private DefaultTableModel model = new DefaultTableModel(data, columnNames) {

        private static final long serialVersionUID = 1L;

        @Override
        public Class<?> getColumnClass(int column) {
            return getValueAt(0, column).getClass();
        }

        @Override
        public boolean isCellEditable(int row, int col) {
            return false;
        }
    };
    private JTable table = new JTable(model);

    public JComponent makeUI() {
        TableColumn column = table.getColumnModel().getColumn(1);
        column.setCellRenderer(new ProgressRenderer());
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                startTask("test");
                startTask("error test");
                startTask("test");
            }
        });
        JPanel p = new JPanel(new BorderLayout());
        p.add(new JScrollPane(table));
        return p;
    }
//http://java-swing-tips.blogspot.com/2008/03/jprogressbar-in-jtable-cell.html

    private void startTask(String str) {
        final int key = model.getRowCount();
        SwingWorker<Integer, Integer> worker = new SwingWorker<Integer, Integer>() {

            private int sleepDummy = new Random().nextInt(100) + 1;
            private int lengthOfTask = 120;

            @Override
            protected Integer doInBackground() {
                int current = 0;
                while (current < lengthOfTask && !isCancelled()) {
                    if (!table.isDisplayable()) {
                        break;
                    }
                    if (key == 2 && current > 60) { //Error Test
                        cancel(true);
                        publish(-1);
                        return -1;
                    }
                    current++;
                    try {
                        Thread.sleep(sleepDummy);
                    } catch (InterruptedException ie) {
                        break;
                    }
                    publish(100 * current / lengthOfTask);
                }
                return sleepDummy * lengthOfTask;
            }

            @Override
            protected void process(java.util.List<Integer> c) {
                model.setValueAt(c.get(c.size() - 1), key, 1);
            }

            @Override
            protected void done() {
                String text;
                int i = -1;
                if (isCancelled()) {
                    text = "Cancelled";
                } else {
                    try {
                        i = get();
                        text = (i >= 0) ? "Done" : "Disposed";
                    } catch (Exception ignore) {
                        ignore.printStackTrace();
                        text = ignore.getMessage();
                    }
                }
                System.out.println(key + ":" + text + "(" + i + "ms)");
            }
        };
        model.addRow(new Object[]{str, 0});
        worker.execute();
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                createAndShowGUI();
            }
        });
    }

    public static void createAndShowGUI() {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.getContentPane().add(new TableCellProgressBar().makeUI());
        frame.setSize(320, 240);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

class ProgressRenderer extends DefaultTableCellRenderer {

    private final JProgressBar b = new JProgressBar(0, 100);

    public ProgressRenderer() {
        super();
        setOpaque(true);
        b.setBorder(BorderFactory.createEmptyBorder(1, 1, 1, 1));
    }

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
        Integer i = (Integer) value;
        String text = "Completed";
        if (i < 0) {
            text = "Error";
        } else if (i < 100) {
            b.setValue(i);
            return b;
        }
        super.getTableCellRendererComponent(table, text, isSelected, hasFocus, row, column);
        return this;
    }
}

但为什么Wwing GUI复杂的使用SwingWorker(需要约最深的知识Java Essential Classes和Generics太)

对于基本的实现Runnable#Thread仅需要invokeLater用于输出到摆动GUI,并在从EDT起动的情况下(从摇摆/ AWT监听器),并且没有任何代码行包含Thread.sleep(int)然后是invokeLater仅谏/生产代码所需

import java.awt.Component;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JProgressBar;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;

public class TableWithProgressBars {

    public static class ProgressRenderer extends JProgressBar implements TableCellRenderer {

        private static final long serialVersionUID = 1L;

        public ProgressRenderer(int min, int max) {
            super(min, max);
            this.setStringPainted(true);
        }

        @Override
        public Component getTableCellRendererComponent(JTable table, Object value,
                boolean isSelected, boolean hasFocus, int row, int column) {
            this.setValue((Integer) value);
            return this;
        }
    }
    private static final int maximum = 100;

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new TableWithProgressBars().createGUI();
            }
        });

    }

    public void createGUI() {
        final JFrame frame = new JFrame("Progressing");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Integer[] oneRow = {0, 0, 0, 0};
        String[] headers = {"One", "Two", "Three", "Four"};
        Integer[][] data = {oneRow, oneRow, oneRow, oneRow, oneRow,};
        final DefaultTableModel model = new DefaultTableModel(data, headers);
        final JTable table = new JTable(model);
        table.setDefaultRenderer(Object.class, new ProgressRenderer(0, maximum));
        table.setPreferredScrollableViewportSize(table.getPreferredSize());
        frame.add(new JScrollPane(table));
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
        new Thread(new Runnable() {

            @Override
            public void run() {
                Object waiter = new Object();
                synchronized (waiter) {
                    int rows = model.getRowCount();
                    int columns = model.getColumnCount();
                    Random random = new Random(System.currentTimeMillis());
                    boolean done = false;
                    while (!done) {
                        int row = random.nextInt(rows);
                        int column = random.nextInt(columns);
                        Integer value = (Integer) model.getValueAt(row, column);
                        value++;
                        if (value <= maximum) {
                            model.setValueAt(value, row, column);
                            try {
                                waiter.wait(15);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                        }
                        done = true;
                        for (row = 0; row < rows; row++) {
                            for (column = 0; column < columns; column++) {
                                if (!model.getValueAt(row, column).equals(maximum)) {
                                    done = false;
                                    break;
                                }
                            }
                            if (!done) {
                                break;
                            }
                        }
                    }
                    frame.setTitle("All work done");
                }
            }
        }).start();
    }
}

我对你看看真正的沉重和长时间运行的任务结束Runnable#Thread(简单,易行,non_buggy和清晰的方式),只有当你对知识Java和Swing非常好,那么你可以考虑SwingWorker