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单击JDialog中的“取消”按钮时发生异常

[英]Exception when clicks Cancel button in JDialog

I am trying to implement a JDialog at the end of a program and collect the user's input. 我正在尝试在程序末尾实现JDialog并收集用户的输入。 My problem is that when the user clicks the "Cancel" button, Eclipse shows: 我的问题是,当用户单击“取消”按钮时,Eclipse显示:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException. 线程“ AWT-EventQueue-0”中的异常java.lang.NullPointerException。

The program seems running OK though afterwards. 该程序似乎运行正常,尽管之后。 I can still start a new game etc. What is the code that I need to add in order to get rid of this NullPointerException ? 我仍然可以开始新游戏等。为了摆脱此NullPointerException ,需要添加什么代码?

If you read the docs you'll see that JOptionPane.showInputDialog returns null if the user canceled the input. 如果您阅读文档,将会看到如果用户取消了输入,则JOptionPane.showInputDialog返回null

You should check your String s for not being before using it. 在使用它之前,应检查String s是否不存在。

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