我对Java很陌生,我正在尝试制作一个基本的用户界面。我可以使用 JButtons 轻松调用 JOptionPanes,但我不能使用它们从另一个类中调用任何内容。
目前我有我的主类、我的 UI 类和处理我的数据的类。
在我处理我的数据的类中,我有一个对数组的两个元素执行基本求和的方法:
public void firstMonth(){
String ans;
int num1 = Integer.parseInt(sortedData[0][0][0]);
int num2 = Integer.parseInt(sortedData[0][0][1]);
int sum = num1 * num2;
ans=String.format("The sum of day1 and day2 is: %s", sum);
JOptionPane.showMessageDialog(null, ans, "Title", JOptionPane.PLAIN_MESSAGE);
}
然后在我的 UI 类中,我尝试在按下其中一个按钮时调用它:
public class UserInterface extends JFrame {
GetData a = new GetData();
private class myhandler implements ActionListener{
public void actionPerformed(ActionEvent event){
if(event.getSource()==button1){
a.firstMonth();
}
}
}
但是当我按下按钮时,我会得到更多我可以忍受的例外情况。有任何想法吗?
对不起,如果这是一个非常基本的问题。
编辑,这是我单击按钮时遇到的异常:
Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: null
at java.lang.Integer.parseInt(Integer.java:454)
at java.lang.Integer.parseInt(Integer.java:527)
at pkg110_term3.GetData.firstMonth(GetData.java:75)
at pkg110_term3.UserInterface$myhandler.actionPerformed(UserInterface.java:71)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
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:6505)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
at java.awt.Component.processEvent(Component.java:6270)
at java.awt.Container.processEvent(Container.java:2229)
at java.awt.Component.dispatchEventImpl(Component.java:4861)
at java.awt.Container.dispatchEventImpl(Container.java:2287)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
at java.awt.Container.dispatchEventImpl(Container.java:2273)
at java.awt.Window.dispatchEventImpl(Window.java:2719)
at java.awt.Component.dispatchEvent(Component.java:4687)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:729)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:688)
at java.awt.EventQueue$3.run(EventQueue.java:686)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:702)
at java.awt.EventQueue$4.run(EventQueue.java:700)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:699)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)