如何不混淆0和取消buttom JoptionPane

Question

   int number = 0;
     boolean condition= false;

   while (!condition) {
        try {
            txt = JOptionPane.showInputDialog(null,
                    "Entrez num :", "Number",
                    JOptionPane.PLAIN_MESSAGE);

            if(txt!=null &&txt!="0" )
            number = Integer.parseInt(txt);

                      if (number <= 1 || number > 12) {
            JOptionPane.showMessageDialog(null, "Integer must be between 1 and 12");
        }else 
              condition=true;

        } catch (NumberFormatException e) {
            JOptionPane.showMessageDialog(null, "you have to enter an integer");
        }

   }

JOptionPane.showMessageDialog(null, "Integer must be between 1 and 12");

非常感谢，

低音

Answer 1

javadoc怎么说？

上面写着：

返回：用户的输入，或null表示用户取消了输入。