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Re:如何调试java程序？(NullPointerException) [Re:lidan_myname]

lidan_myname

发贴: 5
积分: 0

于 2006-11-28 09:42

这是我的源代码．用javac编译过，可通过，但用java就出现以上问题．我郁闷的是电脑显示的信息到底是指错出在哪？有没有总结这些信息的资料参考一下．
import javax.swing.*;
import java.awt.*;

public class GridBagLayoutDemo extends JFrame{
private Container container;
private GridBagLayout layout=new GridBagLayout();
private GridBagConstraints constraints=new GridBagConstraints();
JLabel labUser,labPassword;
JTextField getUser,getPassword;
JButton butLogin;

public GridBagLayoutDemo(){
super("网格布局");
this.setSize(600,400);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

private void setConstraints(GridBagConstraints gbc,int egridx,
int egridy,int egridwith,int egridheight,
int eweightx,int eweighty){
gbc.gridx=egridx;
gbc.gridy=egridy;
gbc.gridwidth=egridwith;
gbc.gridheight=egridheight;
gbc.weightx=eweightx;
gbc.weighty=eweighty;
}

public void setLayout(){
container=getContentPane();
container.setLayout(layout);

constraints.fill=GridBagConstraints.NONE;
constraints.anchor=GridBagConstraints.CENTER;
this.setConstraints(constraints,0,0,1,1,0,0);
labUser=new JLabel("用户名：");
layout.setConstraints(labUser,constraints);
container.add(labUser);

constraints.fill=GridBagConstraints.HORIZONTAL;
this.setConstraints(constraints,1,0,1,1,100,100);
getUser=new JTextField();
layout.setConstraints(getUser,constraints);
container.add(getUser);

constraints.fill=GridBagConstraints.NONE;
constraints.anchor=GridBagConstraints.CENTER;
this.setConstraints(constraints,0,1,1,1,0,0);
labUser=new JLabel("密码：");
layout.setConstraints(labPassword,constraints);
container.add(labPassword);

constraints.fill=GridBagConstraints.HORIZONTAL;
this.setConstraints(constraints,1,1,1,1,100,100);
getPassword=new JTextField();
layout.setConstraints(getPassword,constraints);
container.add(getPassword);

constraints.fill=GridBagConstraints.NONE;
constraints.anchor=GridBagConstraints.CENTER;
this.setConstraints(constraints,0,2,2,1,0,0);
butLogin=new JButton("登录");
layout.setConstraints(butLogin,constraints);
container.add(butLogin);
}

public static void main(String args[]){
GridBagLayoutDemo frame=new GridBagLayoutDemo();
frame.setLayout();
frame.setVisible(true);
}
}

话题树型展开

人气	标题	作者	字数	发贴时间
9271	如何调试java程序？(NullPointerException)	lidan_myname	25	2006-11-25 14:57
7526	Re:如何调试java程序？(NullPointerException)	why	27	2006-11-25 18:07
7535	Re:如何调试java程序？(NullPointerException)	ddddddv	41	2006-11-26 20:17
7387	Re:如何调试java程序？(NullPointerException)	小神	25	2006-11-26 23:38
7429	Re:如何调试java程序？(NullPointerException)	lidan_myname	2328	2006-11-28 09:42
7325	Re:如何调试java程序？(NullPointerException)	zcjl	219	2006-11-28 11:18
7672	Re:如何调试java程序？(NullPointerException)	lidan_myname	12	2006-11-28 11:32

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