我真的不明白这个。当我在 Eclipse 中运行我的程序时，它看起来非常好。它出现在下面：
（请注意，我拖了一些东西来掩盖我的全名，因为这个程序是为学校项目编写的。请忽略这一点）。请注意，一切都会显示
但是，当我在 Eclipse 之外运行程序时...
如您所见，任何与 PaintComponent 相关的对象都不会显示，但其他所有 JText 和 JButton) 都会显示。JOptionPane 消息框也会出现。值得注意的是，没有出现的所有内容都来自一个 JPanel，它不包含任何出现的内容。
以下是未出现的面板代码：
package gui;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Image;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.JPanel;
public class TopPane extends JPanel {
public TopPane(){
setLayout(new FlowLayout());
}
public void paintComponent(Graphics g){
try{
String filename = "logo.jpg";
Image image = ImageIO.read(new File(filename));
g.drawImage(image, 45, -10, null);
String intro = "Program by XXXXXXX XXXX\n";
String intro2 = "The purpose of this program is to make the process of creating a solution";
String intro3 = "less painful by performing the calculations for how much solute needs to be\n";
String intro4 = "added to the solvent. Miscellanious additional information will also be provided.\n";
String intro5 = "\n";
String intro6 = "Please enter infromation in the following format:\n";
String intro7 = "<volume> <molarity> <compound>\n";
String intro8 = "For example:";
String intro9 = "5mL 5M H2SO4";
g.drawString(intro, 30, 70);
g.drawString(intro2, 30, 95);
g.drawString(intro3, 30, 110);
g.drawString(intro4, 30, 125);
g.drawString(intro5, 30, 140);
g.drawString(intro6, 30, 155);
g.drawString(intro7, 30, 170);
g.drawString(intro8, 30, 195);
g.drawString(intro9, 30, 210);
}catch(Exception ex){System.out.println("Failed");}
}
}
这是运行在 Eclipse 之外运行时不起作用的类的类的代码示例：
package gui;
import java.awt.BorderLayout;
import javax.swing.JFrame;
public class MainFrame extends JFrame{
public MainFrame(){
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("Chemistry Lab Assistant");
setSize(550, 300);
//Top Frame
TopPane topPane = new TopPane();
add(topPane);
//Input Pane
InputPane inputPane = new InputPane();
add(inputPane, BorderLayout.SOUTH);
}
}