运行 UI 任务固定次数

在附加到 javax.swing.Timer 的 ActionListener 中，你可以跟踪 Timer 执行 ActionListener 的次数。达到所需的次数后，你可以使用 Timer#stop() 方法停止 Timer。

Timer timer = new Timer( delay, new ActionListener() {
  private int counter = 0;
  @Override
  public void actionPerformed( ActionEvent e ) {
    counter++;//keep track of the number of times the Timer executed
    label.setText( counter + "" );
    if ( counter == 5 ){
      ( ( Timer ) e.getSource() ).stop();
    }
  }
});

下面给出了一个使用此 Timer 的完整可运行示例：它显示了一个 UI，其中标签的文本将从 0 到 5 计数。一旦达到五，Timer 就会停止。

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public final class RepeatFixedNumberOfTimes {
  public static void main( String[] args ) {
    EventQueue.invokeLater( () -> showUI() );
  }
  private static void showUI(){
    JFrame frame = new JFrame( "Repeated fixed number of times example" );
    JLabel label = new JLabel( "0" );

    int delay = 2000;
    Timer timer = new Timer( delay, new ActionListener() {
      private int counter = 0;
      @Override
      public void actionPerformed( ActionEvent e ) {
        counter++;//keep track of the number of times the Timer executed
        label.setText( counter + "" );
        if ( counter == 5 ){
          //stop the Timer when we reach 5
          ( ( Timer ) e.getSource() ).stop();
        }
      }
    });
    timer.setInitialDelay( delay );
    timer.start();

    frame.add( label, BorderLayout.CENTER );
    frame.pack();
    frame.setDefaultCloseOperation( WindowConstants.EXIT_ON_CLOSE );
    frame.setVisible( true );
  }
}