JFrame 组件之间的触发延迟 [英] Firing delay between JFrame components

问题描述

我想展示如何使用 JFrame 直观地执行归并排序.我想要做的是在一些时间延迟后使后续 JLabel 可见.我尝试了很多方法，但所有方法都在同一时刻出现，没有中间延迟.

I want to show how merge sort perform visually using JFrame. What I want to do is to make visible subsequent JLabel with some time delay. I tried many way but all of them appears at same moment with no intermediate delay.

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
        // TODO add your handling code here:
       // jLabel1.setVisible(false);
        jLabel2.setVisible(false);
        jLabel3.setVisible(false);
        jLabel4.setVisible(false);
        jLabel5.setVisible(false);
        jLabel6.setVisible(false);
        jLabel7.setVisible(false);
        final Timer t=new Timer((4000), null);
         final int delay=2000;
        final ActionListener taskPerformer = new ActionListener() {
      public void actionPerformed(ActionEvent evt) {

          jLabel1.setVisible(true);
          t.getDelay();

          jLabel2.setVisible(true);
          t.setDelay(3000);

          jLabel3.setVisible(true);
          t.setDelay(2000);

          jLabel4.setVisible(true);
          t.setDelay(2000);

          jLabel5.setVisible(true);
          t.setDelay(2000);

          jLabel6.setVisible(true);
          t.setDelay(2000);
                }
  };

  new Timer(delay, taskPerformer).start();

但是当我点击按钮时，尽管我一直拖延，但所有标签都出现在同一个时刻.

But when I click button all the lables appear at same momenet though I have kept delay.

推荐答案

这不起作用的原因有很多.首先，javax.swing.Timer 不是这样工作的.它在后台等待，直到给定的延迟过去，然后调用注册的 ActionListener 的 actionPerformed 方法.

There are a number of reasons why this won't work. Firstly, javax.swing.Timer doesn't work this way. It waits in the background until the given delay has past and then calls the registered ActionListeners actionPerformed method.

其次，如果它确实以这种方式工作，它将阻塞事件调度线程，阻止它处理重绘请求.

Secondly, if it did work this way, it would block the Event Dispatching Thread, preventing it from processing repaint requests.

我想您会找到如何使用 Swing 计时器使用.

public class BlinkOut {

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

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

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

        });
    }

    public class TestPane extends JPanel {

        private JLabel[] labels;
        private int[] delays;
        private Timer timer;
        private int index;

        public TestPane() {
            setLayout(new GridLayout(0, 1));
            labels = new JLabel[7];
            for (int index = 0; index < 7; index++) {
                labels[index] = new JLabel("Label " + (index + 1));
                add(labels[index]);
            }
            delays = new int[] {2000, 3000, 2000, 2000, 2000, 2000, 2000};
            JButton hide = new JButton("Hide");
            add(hide);
            hide.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    System.out.println("Click");
                    index = 0;
                    labels[index].setVisible(false);
                    timer.setDelay(delays[index]);
                    timer.start();
                }
            });
            timer = new Timer(delays[0], new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    System.out.println("Tick");
                    timer.stop();
                    index++;
                    if (index < 7) {
                        labels[index].setVisible(false);
                        timer.setDelay(delays[index]);
                        timer.start();
                    }
                }
            });
            timer.setRepeats(false);
            timer.setCoalesce(true);
        }
    }

}

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