当我更新 JList 项目时，它们会以一种奇怪的方式显示

Question

当我将项目添加到模型列表时，它们在JList 上显示得非常奇怪，我不知道为什么它真的很小而且它们也重叠。当我预设一个列表时，它会像setFixedCell 中的设置一样正常显示，你能给我一个提示吗？

import javax.swing.*;

public class test{

    static JFrame mainFrame;
    static JPanel mainPanel;
    static JButton mainSwitch;
    static JList mainList;
    static long firstTime = 0;
    static long times1;
    static int i = 0;
    static boolean x = false;   
    static DefaultListModel model = new DefaultListModel();
    
    // hole Inferface stuff
    test(){
        mainFrame = new JFrame("Zeiterfassung");
        mainPanel = new JPanel();
        mainSwitch = new JButton("ON");
        mainList = new JList(model);
        
        mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        mainFrame.setSize(420, 420);
        mainPanel.setSize(10, 10);
        mainPanel.setLayout(null);
        mainList.setBounds(12, 10, 380, 300);
        mainList.setFixedCellHeight(30);
        mainList.setFixedCellWidth(30);
        mainSwitch.setBounds(12, 320, 380, 50);
        
        mainSwitch.addActionListener(e -> messureTime());
        
        mainPanel.add(mainSwitch);
        mainPanel.add(mainList);
        mainFrame.add(mainPanel);
        
        mainFrame.setVisible(true);
    }
    
    // Method behind the button, normal boolean that changes the text on button "startTracking"
    public static void messureTime() {
        if(x == false) {
            firstTime = System.currentTimeMillis();
            mainSwitch.setText("Stop");
            x = true;
        }
        else if(x==true){
            times1 = (System.currentTimeMillis() - firstTime)/1000;
            model.addElement(String.valueOf(times1) + "Seconds");
            mainSwitch.setText("Start");
            x = false;
            mainList.setFixedCellHeight(5);
            i++;
            mainList.setModel(model);
        }
    }   
    
    public static void main(String[] args) {
        Zeit zeiterfassung = new Zeit();
    }
}

Answer 1

删除将每个列表单元格的高度限制为仅 5 个像素的语句

mainList.setFixedCellHeight(5);