以前是学c++的，现在开始学Java，错误日志也看的不太懂，麻烦各位指教一下。谢谢！！
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.*;
public class GUI
{
public static void main(String args[])
{
new Frame();
}
}
class Frame extends JFrame {
private JLabel lblSum;
private JLabel lblAverage;
private JTextField txtSum;
private JTextField txtAverage;
private JTextField txtInput;
private JButton btnCal;
private JPanel panel;
private JPanel Wpanel;
public Frame()
{
super();
lblSum = new JLabel("和 值");
lblAverage = new JLabel("平 均 值");
txtSum = new JTextField(10);
txtAverage = new JTextField(10);
txtInput = new JTextField(100);
btnCal = new JButton("计算");
panel = new JPanel();
panel.setLayout(new FlowLayout());
panel.add(lblAverage);
panel.add(txtSum);
panel.add(lblSum);
panel.add(txtAverage);
Wpanel = new JPanel();
Wpanel.setLayout(new BorderLayout());
Wpanel.add(txtInput, BorderLayout.NORTH);
Wpanel.add(panel, BorderLayout.CENTER);
Wpanel.add(btnCal, BorderLayout.SOUTH);
getContentPane().add(Wpanel, BorderLayout.CENTER);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(200, 150);
setResizable(true);
setLocationRelativeTo(null);
setVisible(true);
btnCal.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) {
String s1 = txtInput.getText();
String[] strArray = s1.split(",");
int[] intArray = null;
int sum = 0;
int avr = 0;
for(int i = 0;i<strArray.length;i++)
{
intArray[i]=Integer.parseInt(strArray[i]);
sum = sum + intArray[i];
}
avr = sum/intArray.length;
String strsum = sum+"";
String stravr = avr+"";
txtSum.setText(strsum);
txtAverage.setText(stravr);
}
});
}
}
错误日志如下：
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at withbutton.Frame$1.actionPerformed(GUI.java:69)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6535)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6300)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4891)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2750)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
3 个解决方案
#1
intArray为空
#2
第69行代码报空指针，DEBUG进去看看是啥原因。
#3
C++应该也有吧 数组没初始化.....
#1
intArray为空
#2
第69行代码报空指针，DEBUG进去看看是啥原因。
#3
C++应该也有吧 数组没初始化.....