Java第一次做图形界面调试了很久不知道问题出在哪......

Chu1024 2016-11-30 12:14:36

做个图形界面，输入几个值，用逗号隔开，按计算键算出和值和平均值显示在文本框内。图形界面可以出来，一按计算键就报错......
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)

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