8

我有一个消息标签和一个提交按钮。提交按钮将被多次按下，每次按下的操作最多可能需要一分钟。

按下按钮时，我想将消息设置为空，任务完成后，我想将消息设置为“完成”。

private void submitActionPerformed(java.awt.event.ActionEvent evt) {
   message = "";
   updateMessageLabel();

   doTheTask();

   /* this update is apply to the label after completion */
   message = "Complete";
}

是否可以在方法运行之前（或在方法中）更新该消息标签submitActionPerformed()，但在单击按钮之后？

4

2 回答 2

13

虽然Swing 并发教程已经包含了一些关于如何在 Swing 中处理并发的非常好的示例，但请在下面找到一个示例

  • 包含一个复选框以证明 UI 仍然存在
  • 有一个进度条，它从SwingWorker

  • 有一个标签，一旦SwingWorker完成就会更新

    import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JProgressBar;
import javax.swing.SwingWorker;
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.lang.reflect.InvocationTargetException;
import java.util.List;
import java.util.concurrent.ExecutionException;

public class SwingWorkerExample {
  private static JProgressBar PROGRESS_BAR;
  private static JLabel OUTPUT_LABEL;
  private static JFrame createGUI(){
    JFrame testFrame = new JFrame( "TestFrame" );

    PROGRESS_BAR = new JProgressBar(  );
    PROGRESS_BAR.setMinimum( 0 );
    PROGRESS_BAR.setMaximum( 100 );

    OUTPUT_LABEL = new JLabel( "Processing" );

    testFrame.getContentPane().add( PROGRESS_BAR, BorderLayout.CENTER );
    testFrame.getContentPane().add( OUTPUT_LABEL, BorderLayout.SOUTH );

    //add a checkbox as well to proof the UI is still responsive
    testFrame.getContentPane().add( new JCheckBox( "Click me to proof UI is responsive" ), BorderLayout.NORTH );



    testFrame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
    return testFrame;
  }

  public static void main( String[] args ) throws InvocationTargetException, InterruptedException {
    EventQueue.invokeAndWait( new Runnable() {
      @Override
      public void run() {
        JFrame frame = createGUI();

        frame.pack();
        frame.setVisible( true );
      }
    } );
    //start the SwingWorker outside the EDT
    MySwingWorker worker = new MySwingWorker( PROGRESS_BAR, OUTPUT_LABEL );
    worker.execute();
  }
  private static class MySwingWorker extends SwingWorker<String, Double>{
    private final JProgressBar fProgressBar;
    private final JLabel fLabel;
    private MySwingWorker( JProgressBar aProgressBar, JLabel aLabel ) {
      fProgressBar = aProgressBar;
      fLabel = aLabel;
    }

    @Override
    protected String doInBackground() throws Exception {
      int maxNumber = 10;
      for( int i = 0; i < maxNumber; i++ ){
        Thread.sleep( 2000 );//simulate long running process
        double factor = ((double)(i+1) / maxNumber);
        System.out.println("Intermediate results ready");
        publish( factor );//publish the progress
      }
      return "Finished";
    }

    @Override
    protected void process( List<Double> aDoubles ) {
      //update the percentage of the progress bar that is done
      int amount = fProgressBar.getMaximum() - fProgressBar.getMinimum();
      fProgressBar.setValue( ( int ) (fProgressBar.getMinimum() + ( amount * aDoubles.get( aDoubles.size() - 1 ))) );
    }

    @Override
    protected void done() {
      try {
        fLabel.setText( get() );
      } catch ( InterruptedException e ) {
        e.printStackTrace();
      } catch ( ExecutionException e ) {
        e.printStackTrace();
      }
    }
  }
}
于 2012-01-18T21:19:02.570 回答
10

是的，您可以使用SwingWorker线程执行此操作，在方法中执行所有前置submitActionPerformed()活动，例如更新标签，并使用 worker 作为后台作业调用。execute()currentThreaddoTheTask()Thread

我建议您阅读此文档以获取有关SwingWorker 线程的参考

于 2012-01-18T20:19:57.573 回答