線程和任務問題

Question

我目前正在學習Java。我正在創建一個從用戶獲取信息的項目，然後創建sql文件。在那個（冗長的）過程中，我使用任務和線程顯示了一個顯示進度的面板。但是，我發現如果我在開始時等待10秒，代碼將按預期執行，但如果沒有睡眠，程序會立即退出。任何信息非常感謝！

package GUI; 

    import java.awt.event.ActionEvent; 
    import java.awt.event.ActionListener; 
    import javax.swing.JFrame; 

    public class GUIMainPanel implements ActionListener 
    { 
     private static JFrame frame; 

    public GUIMainPanel() 
    { 
      // Code that creates a panel, getting information from the user 
    } 

    public static void main(String[] args) 
    { 
     GUIMainPanel gui = new GUIMainPanel(); 
    } 

    public void actionPerformed(ActionEvent e) 
    { 
     if (e.getActionCommand() == "Continue") 
     { 
      Runnable r1 = new Runnable() 
      { 
       public void run() 
       { 
        // Progress Monitor frame 
        ProgressMonitor pbd = new ProgressMonitor(); 
       } 
      }; 

      Runnable r2 = new Runnable() 
      { 
       public void run() 
       { 
        // Code that creates files and changes the progress 
       } 
      }; 

      Thread thread1 = new Thread(r1); 
      Thread thread2 = new Thread(r2); 

      thread1.start(); 
      thread2.start(); 
     } 
    } 
} 

    package GUI; 

import java.awt.*; 

import javax.swing.*; 
import javax.swing.border.EmptyBorder; 

import Queries.CreateListsQueries; 

import java.beans.*; 

public class ProgressMonitor implements PropertyChangeListener 
{ 
    private static JProgressBar progressBar; // Progress bar showing the progress of the query creation process 
    private static JLabel creatingQueriesLabel; // Label showing information about the current state of the query 
                // creation process 
    private Task task; // Task used to update the progress bar and label based on the current state of the query 
         // creation process 
    private static JFrame frame; 

    /** 
    * Constructor 
    */ 
    public ProgressMonitor() 
    { 
     // Code creating the Progress Monitor Panel and displaying it 

     // Instances of javax.swing.SwingWorker are not reusuable, so 
     // we create new instances as needed. 
     task = new Task(); 
     task.addPropertyChangeListener(this); 
     task.execute(); 
    } 

    class Task extends SwingWorker<Void, Void> 
    { 
     /* 
     * Main task. Executed in background thread. 
     */ 
     @Override 
     public Void doInBackground() 
     { 
      int progress = 0; 
      double tempProgress = 0; 
      String currentQueryText = "Test"; 

      try 
      { 
       // Infamous 10 seconds wait here 
       Thread.sleep(10000); 
      } 
      catch (InterruptedException ignore) 
      { 
       ignore.printStackTrace(); 
      } 

      // Initialize progress property. 
      setProgress(0); 

      while (progress < 100) 
      { 
       progress = GUIMainPanel.getProgress(); 
       setProgress(progress); 
      } 

      return null; 
     } 

     /* 
     * Executed in event dispatching thread 
     */ 
     @Override 
     public void done() 
     { 
      Toolkit.getDefaultToolkit().beep(); 

      frame.setCursor(null); // turn off the wait cursor 

      System.exit(0); 
     } 
    } 

    /** 
    * Invoked when task's progress property changes. 
    */ 
    public void propertyChange(PropertyChangeEvent evt) 
    { 
     if ("progress".equals(evt.getPropertyName())) 
     { 
      int progress = (Integer) evt.getNewValue(); 
      progressBar.setValue(progress); 
     } 
     if ("currentQueryText".equals(evt.getPropertyName())) 
     { 
      String text = (String) evt.getNewValue(); 
      creatingQueriesLabel.setText(text); 
     } 
    } 
} 

Answer 1

終於找到了:)。

一旦我創建了多個任務（見下文），一切都很順利。謝謝大家的幫助:)。

while (GUIMainPanel.getProgress() < 100) 
{ 
    try 
    { 
     Thread.sleep(100); 
    } 
    catch (InterruptedException ignore) 
    { 
     ignore.printStackTrace(); 
    } 

    task = new Task(); 
    task.addPropertyChangeListener(this); 
    task.execute(); 
}