java - 简单Java : How to make string replace and wait then replace again?

Question

我正在做一些东西，Applet 上将会有一个关于 Java 的“计算”页面!所以我想要它做的是首先拉绳并显示“正在计算”。然后一秒钟后它会替换该字符串并显示“正在计算...”，然后再次将该字符串替换为“正在计算...”并循环大约 5 次。有什么简单的方法可以做到这一点吗？

我想让它显示在小程序上!

Answer 1

您想要使用 Swing Timer 或 SwingWorker。请参阅How to use Swing Timers和Worker Threads and SwingWorker了解更多详情。

例如...

  import java.awt.Dimension;
  import java.awt.EventQueue;
  import java.awt.GridBagLayout;
  import java.awt.event.ActionEvent;
  import java.awt.event.ActionListener;
  import javax.swing.JFrame;
  import javax.swing.JLabel;
  import javax.swing.JPanel;
  import javax.swing.Timer;
  import javax.swing.UIManager;
  import javax.swing.UnsupportedLookAndFeelException;

  public class Test {

    public static void main(String[] args) {
      new Test();
    }

    public Test() {
      EventQueue.invokeLater(new Runnable() {
        @Override
        public void run() {
          try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
          } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
            ex.printStackTrace();
          }

          JFrame frame = new JFrame("Testing");
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          frame.add(new TestPane());
          frame.pack();
          frame.setLocationRelativeTo(null);
          frame.setVisible(true);
        }
      });
    }

    public static class TestPane extends JPanel {

      private JLabel label;
      private static final String DOTS = "...";
      private static final String TEXT = "Calculating";
      private int counter;

      public TestPane() {
        setLayout(new GridBagLayout());
        label = new JLabel(getText());
        add(label);

        Timer timer = new Timer(1000, new ActionListener() {
          @Override
          public void actionPerformed(ActionEvent e) {
            counter++;
            if (counter > 3) {
              counter = 0;
            }
            label.setText(getText());
          }
        });
        timer.start();
      }

      protected String getText() {

        String sufix = DOTS.substring(0, counter);
        sufix = String.format("%-3s", sufix);

        return TEXT + sufix;

      }

      @Override
      public Dimension getPreferredSize() {
        return new Dimension(200, 200);
      }

    }

  }

将其添加到小程序与添加到 JFrame 一样简单