Question

求问在java编程中出现这个问题怎么解决啊，求具体解决方法，谢谢

Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: javax.swing.JTextField cannot be cast to java.awt.TextField
at djr.chess.client.FIRClient.keyPressed(FIRClient.java:308)
at java.awt.Component.processKeyEvent(Unknown Source)
at javax.swing.JComponent.processKeyEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

Answer 1

看错误啊Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: javax.swing.JTextField cannot be cast to java.awt.TextField
，类型转换错误，应该是导错包了

追问

新手求具体指导，怎么改过来啊

Answer 2

javax.swing.JTextField cannot be cast to java.awt.TextField看到这句话了吗?你把两个实例弄混淆了,javax.swing.JTextField 只可以用javax.swing.JTextField 来实例化, java.awt.TextField只能用 java.awt.TextField来实例化,不要弄错了.

下面的博客是对两个的比较,还是蛮不错的
http://blog.csdn.net/iamluole/article/details/8142257

追问

求问该怎么改正啊，谢谢

追答

更正的话,如果程序都是用的awt,建议吧java.swing.JTextField删除;反之,如果用的是swing,则吧java.awt.JTextField删除,不过swing是更好的,因为可以跨平台

追问

已经将所有的java.awt.JTextField全部删掉了，可是还有这个问题，那个输入框还是不能用

追答

有报错吗？

Answer 3

JTextField不是继承自TextField而是
java.lang.Object
java.awt.Component
java.awt.Container
javax.swing.JComponent
javax.swing.text.JTextComponent
javax.swing.JTextField
不能强转

Answer 4

你找一下，定义的 JTextFiled 类型的输入框 是不能强制转为TextField 类型的输入框,前者是JDK1.4之后才推出的，在java.swing包中,后者在java.awt包中;

最可能出现问题的地方：

1. (TextFiled)tf ; 将JTextField 类型变量tf强制转化为TextField;

2. 传递参数类型不对；应该传递TexitField类型的参数，而传递成了TextField

具体的错误，要把代码贴出来！

追问

public void keyPressed(KeyEvent e)
{
TextField inputwords = (TextField) e.getSource();

这是显示错误部分的代码，求怎么改正啊，谢谢

追答

TextField inputwords = (TextField) e.getSource();
改为：
JTextField inputwords = (JTextField) e.getSource();

//注解:

e.getSource(); 是获取发生事件的组件；
根据上下文，估计是你定义了一个JTextField 类型的输入框，然后给这个输入框添加了一个键盘看下的事件。所以，e.getSource();获取的组件应该是JTextField 类型的，而不是TextField。

Answer 5

别用强制类型转换