Question

我现在正在研究如何使用摆动计时器2天，并试图弄清楚如何更改我在JFrame中心的图像。截至目前，我的程序运行正常，但图像并没有改变我想要的方式。该类仅用作测试，因此可能没有正确的java语法。

    package hauntedHouseAdventure;

import java.awt.BorderLayout;

    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import java.io.IOException;

    import javax.swing.ImageIcon;
    import javax.swing.JButton;
    import javax.swing.JFrame;
    import javax.swing.JLabel;
    import javax.swing.JPanel;
    import javax.swing.Timer;

public class timertest {
    static JFrame sceneOne = new JFrame();
    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub


    ImageIcon image = new ImageIcon(
            "/Users/computerscience2/Desktop/dark-forest-night-image.jpg");
    JLabel imageLabel = new JLabel("", image, JLabel.CENTER);
    JPanel panel = new JPanel(new BorderLayout());
    panel.add(imageLabel, BorderLayout.NORTH);
    sceneOne.add(panel);
    sceneOne.setResizable(false);
    imageLabel.setVisible(true);
    sceneOne.pack();

    JButton leave=new JButton("Leave");
    JButton stay= new JButton ("Stay");
    leave.addActionListener(new ActionListener(){

        public void actionPerformed(ActionEvent e)
        {
            //Execute when button is pressed
            sceneOne.setVisible(false);
        }
    });      
    stay.addActionListener(new ActionListener(){

        public void actionPerformed(ActionEvent f)
        {
            //Execute when button is pressed
           sceneOne.setVisible(false);
        }
    });      

    panel.add(leave, BorderLayout.EAST);
    panel.add(stay, BorderLayout.WEST);


    JLabel label1 = new JLabel("Test");

    label1.setText("<html><font color='red'> It was approximately 11:30 pm. The night sky was black not a single star piercing through the darkness"
            + "except the thick and powerful moonlight."
            + "<br>"
            + "You are alone leaving a costume party at a friend's place."
            + "It was rather boring and you decided to leave early."
            + "A stutter is heard and your"
            + "<br>"
            + "car begins to shake"
            + "Your headlights and car lights crack. The engine is left dead silent."
            + "You are left in a total silence"
            + "and baked in merely the moonlight."
            + "<br>"
            + "There is a mere second of silence till a harsh chill ripes through the"
            + "car like a bullet through paper. You are left dumbfounded. What do you do?</font><html>");
    label1.setHorizontalAlignment(JLabel.CENTER);
    label1.setVerticalAlignment(JLabel.BOTTOM);
    label1.setVisible(true);
    label1.setOpaque(false);

  panel.add(label1); 

  final ActionListener updater = new ActionListener() {
      @Override
      public void actionPerformed(ActionEvent event) {

          ImageIcon image = new ImageIcon(
                  "/Users/computerscience2/Desktop/image-slider-5.jpg");
          JLabel imageLabel = new JLabel("", image, JLabel.CENTER);
          JPanel panel = new JPanel(new BorderLayout());
          panel.add(imageLabel, BorderLayout.NORTH);
          sceneOne.add(panel);

          }
  };



  Timer timer = new Timer(1000, updater);

  timer.start();





  sceneOne.setSize(2000,1000);
    sceneOne.setTitle("The Car");
    sceneOne.setVisible(true);
    sceneOne.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    sceneOne.setLocation(250, 200);
}

}

Answer 1

我没有详细查看但是要更改标签上的图像，那么您不需要创建新控件，只需要更改现有图像。

  public void actionPerformed(ActionEvent event) {

      ImageIcon image = new ImageIcon(
              "/Users/computerscience2/Desktop/image-slider-5.jpg");
      imageLabel.setIcon(image);

  }

您还需要将imageLabel设置为成员变量或最终变量，以便actionPerformed方法可以看到它。

Answer 2

我在你的代码中看到了两个问题。

您正在将新图像添加到面板，但不会删除旧图像。
您没有告诉您的框架您的组件发生了变化，他需要重新绘制。

我认为最好的方法就是更改imageLabel的图标。像这样：

final JLabel imageLabel = new JLabel("", image, JLabel.CENTER);
......
final ActionListener updater = new ActionListener() {

   public void actionPerformed(ActionEvent e) {
      ImageIcon image = new ImageIcon("/Users/computerscience2/Desktop/image-slider-5.jpg");
      imageLabel.setIcon(image);
      imageLabel.updateUI(); //Tell to your frame he needs to redraw the image
   }
};

如何根据时间进行一次JLabel更改

2 个答案: