java - 如何使我的 SwingWorker 示例正常工作？

Question

我制作了自己的 SwingWorker 示例以熟悉它的工作原理。

我想做的是:单击按钮时，我希望在任务完成之前出现一个进度条。我想简单地删除进度条并向对话框添加一个字符串。

单击按钮时，进度条会出现但不会消失。 (永远不会在 10 秒后删除进度条并且永远不会放置标签)

这是一个 SSCCE:

package swingtesting;

import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JProgressBar;
import javax.swing.SwingWorker;

public class SwingTesting {

    /**
     * Creates a frame that will hold a simple button to make use of SwingWorker
     */
     public static void main(String[] args) {
         // TODO code application logic here
         JFrame frame = new JFrame();
         JButton button = new JButton();

         button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                new GuiWorker().execute();
            }
         });
         button.setText("Test Me");
         frame.getContentPane().add(button);
         frame.pack();
         frame.setVisible(true);
    }
}

class GuiWorker extends SwingWorker<Integer, Integer> {

    /*
     * This should just create a frame that will hold a progress bar until the
     * work is done. Once done, it should remove the progress bar from the dialog
     * and add a label saying the task complete.
     */

    private JFrame frame = new JFrame();
    private JDialog dialog = new JDialog(frame, "Swingworker test", true);
    private JProgressBar progressBar = new JProgressBar();


    public GuiWorker() {
        progressBar.setString("Waiting on time");
        progressBar.setStringPainted(true);
        progressBar.setIndeterminate(true);
        dialog.getContentPane().add(progressBar);
        dialog.pack();
        dialog.setVisible(true);
    }

    @Override
    protected Integer doInBackground() throws Exception {
        Thread.sleep(10000);
        return 0;
    }

    @Override
    protected void done() {
        JLabel label = new JLabel("Task Complete");
        dialog.getContentPane().remove(progressBar);
        dialog.getContentPane().add(label);
    }

}

Answer 1

这里是你的代码的更新版本，它可以工作

import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JProgressBar;
import javax.swing.SwingWorker;

public class SwingTesting {

  public static void main(String[] args) {
    EventQueue.invokeLater( new Runnable() {
      @Override
      public void run() {
        JFrame frame = new JFrame();
        JButton button = new JButton();
        button.addActionListener(new ActionListener() {
          @Override
          public void actionPerformed(ActionEvent e) {
            new GuiWorker().execute();
          }
        });
        button.setText("Test Me");
        frame.getContentPane().add(button);
        frame.pack();
        frame.setVisible(true);
      }
    } );

  }
}

class GuiWorker extends SwingWorker<Integer, Integer> {

  /*
  * This should just create a frame that will hold a progress bar until the
  * work is done. Once done, it should remove the progress bar from the dialog
  * and add a label saying the task complete.
  */

  private JFrame frame = new JFrame();
  private JDialog dialog = new JDialog(frame, "Swingworker test", true);
  private JProgressBar progressBar = new JProgressBar();


  public GuiWorker() {
    progressBar.setString("Waiting on time");
    progressBar.setStringPainted(true);
    progressBar.setIndeterminate(true);
    dialog.getContentPane().add(progressBar);
    dialog.pack();
    dialog.setModal( false );
    dialog.setVisible(true);
  }

  @Override
  protected Integer doInBackground() throws Exception {
    System.out.println( "GuiWorker.doInBackground" );
    Thread.sleep(1000);
    return 0;
  }

  @Override
  protected void done() {
    System.out.println("done");
    JLabel label = new JLabel("Task Complete");
    dialog.getContentPane().remove(progressBar);
    dialog.getContentPane().add(label);
    dialog.getContentPane().validate();
  }

}

关键点是设置模型对话框可见 block ，直到对话框被释放。因此，当您切换组件时，将其设置为非模态修复 + validate 对内容 Pane 的调用。我还调整了您的主要方法以在 EDT 上运行，并添加了一些 System.out 调用。如果删除 setModal( false ) 调用，您将看到在关闭对话框之前不会打印这些语句