SwingWorker ProgressBar

Question

我想要獲得一個進度條來準確地反映我的SwingWorker。但我真的不知道該怎麼做。我得到了酒吧，只是做一個靜態動畫，直到操作完成，但我想要一個真正的活動酒吧。

/* 
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* and open the template in the editor. 
*/ 
package frglauncher; 

import java.io.File; 
import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.RandomAccessFile; 
import java.net.MalformedURLException; 
import java.net.URL; 
import java.nio.channels.Channels; 
import java.nio.channels.ReadableByteChannel; 
import java.util.Enumeration; 
import java.util.jar.JarEntry; 
import java.util.jar.JarFile; 
import java.util.logging.Level; 
import java.util.logging.Logger; 
import javax.swing.JLabel; 
import javax.swing.JProgressBar; 
import javax.swing.SwingWorker; 

/** 
* 
* @author KYLE-LAPTOP 
*/ 
class DownloadWorker extends SwingWorker<String, Object> { 

    private String game; 
    private JProgressBar bar; 
    private JLabel label; 

    public DownloadWorker(JProgressBar bar, String game, JLabel label) { 
     this.game = game; 
     this.bar = bar; 
     this.label = label; 
    } 

    @Override 
    public String doInBackground() { 

     // Download here 
     label.setText("test"); 
     try { 
      // ProgressBar/Install 
      System.out.println("FILELOCATION:\n----------"); 
      String URL_LOCATION = "http://www.futureretrogaming.tk/gamefiles/ProfessorPhys.jar"; 
      String LOCAL_FILE = ("\\" + game + "\\"); 
      File localfile = new File(LOCAL_FILE); 
      if (localfile.exists()) { 
       System.out.println("Directory exists!"); 
      } 
      else { 
       System.out.println("Directory doesn't exist! Creating..."); 
       localfile.mkdir(); 
       if (localfile.exists()) { 
        System.out.println("Directory created!"); 
       } 
      } 
      System.out.println("LOCALFILE:\n-------"); 
      System.out.println(LOCAL_FILE); 
      URL website = new URL(URL_LOCATION); 
      ReadableByteChannel rbc = Channels.newChannel(website.openStream()); 
      FileOutputStream fos = new FileOutputStream(LOCAL_FILE + "\\ProfessorPhys.jar\\"); 
      fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE); 
      System.out.println("--------\nDone Downloading\n---------"); 

      RandomAccessFile randomAccessFile = null; 

      File file = new File(LOCAL_FILE + "ProfessorPhys.jar\\"); 
      JarFile jar = new JarFile(file); 
      Enumeration enum1 = jar.entries(); 
      while (enum1.hasMoreElements()) { 
       JarEntry file1 = (JarEntry) enum1.nextElement(); 
       System.out.println("Directory to extract: " + LOCAL_FILE); 
       System.out.println("\n" + file1.getName() + "\n"); 
       File f = new File(file1.getName()); 
       if (file1.isDirectory()) { // If it's a directory, create it 
        f.mkdir(); 
        continue; 
       } 
       try (InputStream is1 = jar.getInputStream(file1)) { 
        FileOutputStream fos1 = new FileOutputStream(f); 
        while (is1.available() > 0) { // Write contents of 'is' to 'fos' 
         fos1.write(is1.read()); 
        } 
        fos1.close(); 
       } 
      } 
     } 
     catch (FileNotFoundException ex) { 
      Logger.getLogger(DownloadWorker.class.getName()).log(Level.SEVERE, null, ex); 
     } 
     catch (MalformedURLException ex) { 
      Logger.getLogger(DownloadWorker.class.getName()).log(Level.SEVERE, null, ex); 
     } 
     catch (IOException ex) { 
      Logger.getLogger(DownloadWorker.class.getName()).log(Level.SEVERE, null, ex); 
     } 
     return "done"; 
    } 

    @Override 
    protected void done() { 

     // Done 
     label.setText("Download of " + game + "is done."); 
     System.exit(0); 
    } 
} 

Answer 1

幾件事情：

1. 有四個規則遵循SwingWorker。你可以參考這個圖表：。

所以，此代碼：

@Override 
public String doInBackground() { 
    //download here 
    label.setText("test"); 

違反了規則。您的label.setText()應該移到構造函數中。

發送「更新」到Swing組件（如您的進度條），你要使用的process()方法，它調用使用publish()從doInBackground()內。您的秒SwingWorker參數反映您想要傳遞的值的類型。我附上了兩個SSCCE。一個通過Integer到process()方法，另一個通過String。應該讓你知道發生了什麼。

SSCCE使用Integer：

import java.util.List; 
import java.util.concurrent.ExecutionException; 
import javax.swing.JFrame; 
import javax.swing.JLabel; 
import javax.swing.JOptionPane; 
import javax.swing.JPanel; 
import javax.swing.JProgressBar; 
import javax.swing.SwingUtilities; 
import javax.swing.SwingWorker; 

/** 
* 
* @author Ryan 
*/ 
public class Test { 

    public static void main(String args[]) { 
     SwingUtilities.invokeLater(new Runnable() { 
      @Override 
      public void run() { 
       go(); 
      } 
     }); 
    } 

    public static void go() { 
     JFrame frame = new JFrame(); 
     JPanel panel = new JPanel(); 
     JLabel label = new JLabel("Loading..."); 
     JProgressBar jpb = new JProgressBar(); 
     jpb.setIndeterminate(false); 
     int max = 1000; 
     jpb.setMaximum(max); 
     panel.add(label); 
     panel.add(jpb); 
     frame.add(panel); 
     frame.pack(); 
     frame.setSize(200,90); 
     frame.setLocationRelativeTo(null); 
     frame.setVisible(true); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     new Task_IntegerUpdate(jpb, max, label).execute(); 

    } 

    static class Task_IntegerUpdate extends SwingWorker<Void, Integer> { 

     JProgressBar jpb; 
     int max; 
     JLabel label; 
     public Task_IntegerUpdate(JProgressBar jpb, int max, JLabel label) { 
      this.jpb = jpb; 
      this.max = max; 
      this.label = label; 
     } 

     @Override 
     protected void process(List<Integer> chunks) { 
      int i = chunks.get(chunks.size()-1); 
      jpb.setValue(i); // The last value in this array is all we care about. 
      System.out.println(i); 
      label.setText("Loading " + i + " of " + max); 
     } 

     @Override 
     protected Void doInBackground() throws Exception { 
      for(int i = 0; i < max; i++) { 
       Thread.sleep(10); // Illustrating long-running code. 
       publish(i); 
      } 
      return null; 
     } 

     @Override 
     protected void done() { 
      try { 
       get(); 
       JOptionPane.showMessageDialog(jpb.getParent(), "Success", "Success", JOptionPane.INFORMATION_MESSAGE); 
      } catch (ExecutionException | InterruptedException e) { 
       e.printStackTrace(); 
      } 
     } 
    } 
} 

SSCCE使用String：

import java.util.List; 
import java.util.concurrent.ExecutionException; 
import javax.swing.JFrame; 
import javax.swing.JLabel; 
import javax.swing.JOptionPane; 
import javax.swing.JPanel; 
import javax.swing.JProgressBar; 
import javax.swing.SwingUtilities; 
import javax.swing.SwingWorker; 

/** 
* 
* @author Ryan 
*/ 
public class Test2 { 

    public static void main(String args[]) { 
     SwingUtilities.invokeLater(new Runnable() { 
      @Override 
      public void run() { 
       go(); 
      } 
     }); 
    } 

    public static void go() { 
     JFrame frame = new JFrame(); 
     JPanel panel = new JPanel(); 
     JLabel label = new JLabel("Loading..."); 
     JProgressBar jpb = new JProgressBar(); 
     jpb.setIndeterminate(true); 
     panel.add(label); 
     panel.add(jpb); 
     frame.add(panel); 
     frame.pack(); 
     frame.setSize(200,90); 
     frame.setLocationRelativeTo(null); 
     frame.setVisible(true); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     new Task_StringUpdate(label).execute(); 
    } 

    static class Task_StringUpdate extends SwingWorker<Void, String> { 

     JLabel jlabel; 
     public Task_StringUpdate(JLabel jlabel) { 
      this.jlabel = jlabel; 
     } 

     @Override 
     protected void process(List<String> chunks) { 
      jlabel.setText(chunks.get(chunks.size()-1)); // The last value in this array is all we care about. 
      System.out.println(chunks.get(chunks.size()-1)); 
     } 

     @Override 
     protected Void doInBackground() throws Exception { 

      publish("Loading Step 1..."); 
      Thread.sleep(1000); 
      publish("Loading Step 2..."); 
      Thread.sleep(1000); 
      publish("Loading Step 3..."); 
      Thread.sleep(1000); 
      publish("Loading Step 4..."); 
      Thread.sleep(1000); 

      return null; 
     } 

     @Override 
     protected void done() { 
      try { 
       get(); 
       JOptionPane.showMessageDialog(jlabel.getParent(), "Success", "Success", JOptionPane.INFORMATION_MESSAGE); 
      } catch (ExecutionException | InterruptedException e) { 
       e.printStackTrace(); 
      } 
     } 
    } 
}