我创建了一个GUI应用，其中正在执行4个单独的SwingWorker线程。他们的进度由单独的进度条和旁边的数字指示（动态更新）。底部还有一个“总计”标签，该标签应该是所有4个线程的进度之和。但是，由于比赛条件，总计未正确计算。到目前为止，我已尝试使用syncrhonized关键字并利用SwingWorker的publish()和process()方法。没事。还有一个“暂停”和“继续”按钮可以使用，但是在“ GrandTotal”数字中却产生了更大的差异。
这是我的对话框代码：
public class ThreadTestDialog extends JDialog {
private JPanel contentPane;
private JButton buttonStart;
private JButton buttonPause;
private JProgressBar progressBar1;
private JProgressBar progressBar2;
private JProgressBar progressBar3;
private JProgressBar progressBar4;
private JButton buttonResume;
private JLabel labelThread1;
private JLabel labelThread2;
private JLabel labelThread3;
private JLabel labelThread4;
private JLabel labelThread1Total;
private JLabel labelThread2Total;
private JLabel labelThread3Total;
private JLabel labelThread4Total;
private JLabel labelGrandTotal;
private JLabel labelGrandTotalValue;
public AppThread thread1 = new AppThread(labelThread1Total, progressBar1, 30, labelGrandTotalValue);
public AppThread thread2 = new AppThread(labelThread2Total, progressBar2, 75, labelGrandTotalValue);
public AppThread thread3 = new AppThread(labelThread3Total, progressBar3, 50, labelGrandTotalValue);
public AppThread thread4 = new AppThread(labelThread4Total, progressBar4, 20, labelGrandTotalValue);
public ThreadTestDialog() {
setContentPane(contentPane);
setModal(true);
getRootPane().setDefaultButton(buttonStart);
buttonStart.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
onStart();
}
});
buttonPause.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
onPause();
}
});
buttonResume.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
onResume();
}
});
// call dispose() when cross is clicked
setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
dispose();
}
});
// call dispose() on ESCAPE
contentPane.registerKeyboardAction(new ActionListener() {
public void actionPerformed(ActionEvent e) {
dispose();
}
}, KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE, 0), JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
}
private void onStart() {
thread1.execute();
thread2.execute();
thread3.execute();
thread4.execute();
}
private void onPause() {
thread1.setFlag(false);
thread2.setFlag(false);
thread3.setFlag(false);
thread4.setFlag(false);
}
private void onResume() {
int tempValue;
tempValue = thread1.getValue();
thread1 = new AppThread(tempValue, labelThread1Total, progressBar1, 30, labelGrandTotalValue);
thread1.execute();
tempValue = thread2.getValue();
thread2 = new AppThread(tempValue, labelThread2Total, progressBar2, 75, labelGrandTotalValue);
thread2.execute();
tempValue = thread3.getValue();
thread3 = new AppThread(tempValue, labelThread3Total, progressBar3, 50, labelGrandTotalValue);
thread3.execute();
tempValue = thread4.getValue();
thread4 = new AppThread(tempValue, labelThread4Total, progressBar4, 20, labelGrandTotalValue);
thread4.execute();
}
public static void main(String[] args) {
ThreadTestDialog dialog = new ThreadTestDialog();
dialog.pack();
dialog.setVisible(true);
System.exit(0);
}
}
这是我的SwingWorker自定义类：
import javax.swing.*;
import java.util.List;
public class AppThread extends SwingWorker<Void, Integer> {
private int value=0;
private int sleepTime;
private JLabel label;
private JProgressBar progressBar;
private JLabel grandTotal;
private boolean flag=true;
public AppThread (JLabel label, JProgressBar progressBar, int sleepTime, JLabel grandTotal) {
this.sleepTime = sleepTime;
this.label = label;
this.progressBar = progressBar;
this.grandTotal = grandTotal;
}
public AppThread (int value, JLabel label, JProgressBar progressBar, int sleepTime, JLabel grandTotal) {
this.value = value;
this.sleepTime = sleepTime;
this.label = label;
this.progressBar = progressBar;
this.grandTotal = grandTotal;
}
public Void doInBackground() {
for (int i = value; i <= 100; i++) {
if (!flag) break;
this.value = i;
try {
Thread.sleep(sleepTime);
} catch (InterruptedException e) {
e.printStackTrace();
}
label.setText(Integer.toString(value));
progressBar.setValue(value);
progressBar.setStringPainted(true);
grandTotal.setText(Integer.toString(Integer.parseInt(grandTotal.getText()) + 1));
}
return null;
}
public void done() {
}
public void setFlag(boolean flag) {
this.flag = flag;
}
public int getValue() {
return value;
}
}
}
我将非常感谢您提出有关如何同步工作线程，以便它们正确更新“ GrandTotal”标签的建议。
您违反了Swing的线程规则，从事件分派线程的上下文外部更新了UI，SwingWorker可以帮助您。
[避免将您的UI对象的引用传递给SwingWorker，而是使用其process方法来更新某些状态模型，或者使用PropertyChangeListener支持来间接地更新UI。
下面是一个简单的示例，它使用PropertyChangeListener支持来更新进度条。
注意，我已经将AppThread与UI分离了，所以UI现在承担了更新UI的责任。该示例还可以动态扩展，因此您可以通过简单地更新创建它们的AppThread来增加for-loop的数量。
ThreadTestDialogimport java.awt.EventQueue; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.util.HashMap; import java.util.Map; import java.util.Random; import javax.swing.JButton; import javax.swing.JDialog; import javax.swing.JProgressBar; import javax.swing.UIManager; import javax.swing.UnsupportedLookAndFeelException; public class ThreadTestDialog extends JDialog { private JButton buttonStart; private Map<AppThread, JProgressBar> progressBars = new HashMap<>(4); private JProgressBar pbGrandTotal; public ThreadTestDialog() { setModal(true); getRootPane().setDefaultButton(buttonStart); buttonStart = new JButton("Start"); buttonStart.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { onStart(); } }); // call dispose() when cross is clicked setDefaultCloseOperation(DISPOSE_ON_CLOSE); setLayout(new GridBagLayout()); GridBagConstraints gbc = new GridBagConstraints(); gbc.gridwidth = GridBagConstraints.REMAINDER; Random rnd = new Random(); for (int index = 0; index < 4; index++) { AppThread appThread = new AppThread(rnd.nextInt(1000)); appThread.addPropertyChangeListener(new PropertyChangeListener() { @Override public void propertyChange(PropertyChangeEvent evt) { AppThread worker = (AppThread)evt.getSource(); String name = evt.getPropertyName(); if (name.equals("progress")) { JProgressBar pb = progressBars.get(worker); pb.setValue(worker.getProgress()); } else if (name.equals("done")) { // Now you can do something when the worker completes... } updateTotalProgress(); } }); JProgressBar pb = new JProgressBar(0, 100); progressBars.put(appThread, pb); add(pb, gbc); } pbGrandTotal = new JProgressBar(0, progressBars.size() * 100); add(pbGrandTotal, gbc); add(buttonStart, gbc); } protected void updateTotalProgress() { int totalProgress = 0; for (Map.Entry<AppThread, JProgressBar> entry : progressBars.entrySet()) { totalProgress += entry.getKey().getProgress(); } pbGrandTotal.setValue(totalProgress); } private void onStart() { for (Map.Entry<AppThread, JProgressBar> entry : progressBars.entrySet()) { entry.getKey().execute(); } } public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { ex.printStackTrace(); } ThreadTestDialog dialog = new ThreadTestDialog(); dialog.pack(); dialog.setVisible(true); } }); } }
AppThreadimport javax.swing.SwingWorker; public class AppThread extends SwingWorker<Void, Integer> { private int value = 0; private int sleepTime; public AppThread(int sleepTime) { this.sleepTime = sleepTime; } public Void doInBackground() { for (int i = value; i <= 100; i++) { this.value = i; try { Thread.sleep(sleepTime); } catch (InterruptedException e) { e.printStackTrace(); } setProgress(value); } return null; } }