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import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JOptionPane;
public class Guiii extends JFrame{
private JButton menu;
private JButton custom;
public Guiii(){
super ("The Title");
setLayout(new FlowLayout());
menu = new JButton("menu Button");
add (menu);
Icon b = new ImageIcon (getClass().getResource("button.png"));
Icon x = new ImageIcon (getClass().getResource("greenbutton.png"));
custom = new JButton("Custom",b);
custom.setRolloverIcon(x);
add (custom);
HandlerClass handler = new HandlerClass();
menu.addActionListener(handler);
custom.addActionListener(handler);
}
private class HandlerClass implements ActionListener{
public void actionPerformed(ActionEvent event){
JOptionPane.showMessageDialog(null, String.format("~s", event.getActionCommand()));
}
}
}
這是我的代碼,我有一些麻煩,它不工作,我已經做出了主要的,但錯誤都出現了任何人都可以幫我解釋一下代碼是如何工作的KHG軟件工程,GUI
這些都是錯誤
Exception in thread "main" java.lang.NullPointerException
at javax.swing.ImageIcon.<init>(ImageIcon.java:205)
at Guiii.<init>(Guiii.java:22)
at main.main(main.java:7)
這是代碼的其餘部分,但它必須是在另一個文件:
import javax.swing.JFrame;
public class main {
public static void main(String[] args) {
// TODO Auto-generated method stub
Guiii o = new Guiii();
o.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
o.setSize(300,200);
o.setVisible(true);
}
}
什麼是錯誤?.. –
[link]線程「main」中的異常java.lang.NullPointerException \t at javax.swing.ImageIcon。(ImageIcon.java:205) \t at Guiii。 (Guiii.java:22) \t at main.main(main.java:7) –
AHMER93
這不是完整的code.right? –