JOptionPane的取消按钮(JOptionPane cancel button)

伙计们我试着去使用JOptionPane的，但是，如果我输入了错误的输入值，并且不退出PROGRAMM了取消按钮的响应。 任何想法是对子级非常有用的！

int n = 0, k = 0;

Students stu = new Students();      

while (n <= 0) { 

     try { 
       n = Integer.parseInt(JOptionPane.showInputDialog(stu, "Enter the number of people","Input", JOptionPane.INFORMATION_MESSAGE));

       if (n <= 0) {
        OptionPane.showMessageDialog(stu, "You have given a wrong input!", 
             "Warning", JOptionPane.WARNING_MESSAGE);
       }    
    }

    catch (Exception e) { 
          JOptionPane.showMessageDialog(stu, "You have given a wrong input!",
               "Warning",  JOptionPane.WARNING_MESSAGE);
          n = 0; 
    }
}

Answer 1:

这是你想要的东西：

int n;
String code = JOptionPane.showInputDialog(null, 
"Enter the size of the group", 
"Team Combination Finder", 
JOptionPane.INFORMATION_MESSAGE);

if (code == null) {
  System.out.println("This is cancel button");
  System.exit(0);
} else if (code.equalsIgnoreCase("")) {
  System.out.println("This is OK button without input");
} else {
  try {
    n = Integer.parseInt(code);
    if (n <= 0) {
      System.out.println("This is wrong input");
    } else {
      System.out.println("This is right input");
    }
  } catch (Exception e) {
    System.out.println("You must input numeric only");
  }
}

看看它是否适合你:)

Answer 2:

作为一个方面说明，我认为拼写错误JOptionPane （第11行）应该不必要引发异常。

Answer 3:

你已经证明了OptionDialog后，你必须使用一个break语句，为了打破循环。 JOptionPane的不知道你的循环。

或者使用

System.exit(ErrorCode);

代替break;

更新

所以我觉得你想要的是这样的：

String input = JOptionPane.showInputDialog(null, "Enter name :  ", "New Record!", 

while (n <= 0) { 
 try {
   String input = JOptionPane.showInputDialog(stu, "Enter the number of people","Input", JOptionPane.INFORMATION_MESSAGE);
   if(input == null || input.length() == 0)
   {
    OptionPane.showMessageDialog(stu, "You have given a wrong input!", 
         "Warning", JOptionPane.WARNING_MESSAGE);
      System.exit(0);
   }

   n = Integer.parseInt(input);

   if (n <= 0) {
    OptionPane.showMessageDialog(stu, "You have given a wrong input!", 
         "Warning", JOptionPane.WARNING_MESSAGE);
   }    
}

catch (Exception e) { 
      JOptionPane.showMessageDialog(stu, "You have given a wrong input!",
           "Warning",  JOptionPane.WARNING_MESSAGE);
      n = 0; 
}

}

文章来源: JOptionPane cancel button