JOptionPane Yes or No window

问题:

I am trying to create a message with a Yes or No button. Then a window will appear with a certain message that depends on if the user clicked Yes or No.

Here is my code:

public class test{
    public static void main(String[] args){

        //default icon, custom title
        int n = JOptionPane.showConfirmDialog(
            null,
            "Would you like green eggs and ham?",
            "An Inane Question",
            JOptionPane.YES_NO_OPTION);

        if(true){
            JOptionPane.showMessageDialog(null, "HELLO");
        }
        else {
            JOptionPane.showMessageDialog(null, "GOODBYE");
        }

        System.exit(0);
    }
}

Right now it prints HELLO whether or not you press Yes or No. How do I get it to show GOODBYE when the user chooses No?

回答1:

"if(true)" will always be true and it will never make it to the else. If you want it to work correctly you have to do this:

    int reply = JOptionPane.showConfirmDialog(null, message, title, JOptionPane.YES_NO_OPTION);
        if (reply == JOptionPane.YES_OPTION) {
          JOptionPane.showMessageDialog(null, "HELLO");
        }
        else {
           JOptionPane.showMessageDialog(null, "GOODBYE");
           System.exit(0);
        }

回答2:

You are always checking for a true condition, hence your message will always show.

You should replace your if (true) statement with if ( n == JOptionPane.YES_OPTION)

When one of the showXxxDialog methods returns an integer, the possible values are:

YES_OPTION NO_OPTION CANCEL_OPTION OK_OPTION CLOSED_OPTION

From here

回答3:

You can fix it with this:

if(n == JOptionPane.YES_OPTION)
{
    JOptionPane.showMessageDialog(null, "HELLO");
}
else
{
    JOptionPane.showMessageDialog(null, "GOODBYE");
}

回答4:

You can do this a whole simpler:

int test = JOptionPane.showConfirmDialog(null, "Would you like green eggs and ham?", "An insane question!");
switch(test) {
    case 0: JOptionPane.showMessageDialog(null, "HELLO!"); //Yes option
    case 1: JOptionPane.showMessageDialog(null, "GOODBYE!"); //No option
    case 2: JOptionPane.showMessageDialog(null, "GOODBYE!"); //Cancel option
}

回答5:

You are writing if(true) so it will always show "Hello " message.

You should take decision on the basis of value of n returned.

回答6:

Code for Yes and No Message

      int n = JOptionPane.showConfirmDialog(  
                null,
                "sample question?!" ,
                "",
                JOptionPane.YES_NO_OPTION);

      if(n == JOptionPane.YES_OPTION)
      {
          JOptionPane.showMessageDialog(null, "Opening...");
      }
      else
      {
          JOptionPane.showMessageDialog(null, "Goodbye");
          System.exit(0);

回答7:

Something along these lines ....

   //default icon, custom title
int n = JOptionPane.showConfirmDialog(null,"Would you like green eggs and ham?","An Inane Question",JOptionPane.YES_NO_OPTION);

String result = "?";
switch (n) {
case JOptionPane.YES_OPTION:
  result = "YES";
  break;
case JOptionPane.NO_OPTION:
  result = "NO";
  break;
default:
  ;
}
System.out.println("Replace? " + result);

you may also want to look at DialogDemo

回答8:

For better understand how it works!

int n = JOptionPane.showConfirmDialog(null, "Yes No Cancel", "YesNoCancel", JOptionPane.YES_NO_CANCEL_OPTION);
    if(n == 0)
        {
        JOptionPane.showConfirmDialog(null, "You pressed YES\n"+"Pressed value is = "+n);
        }
    else if(n == 1)
        {
        JOptionPane.showConfirmDialog(null, "You pressed NO\n"+"Pressed value is = "+n);
        }
    else if (n == 2)
        {
        JOptionPane.showConfirmDialog(null, "You pressed CANCEL\n"+"Pressed value is = "+n);
        }
    else if (n == -1)
        {
        JOptionPane.showConfirmDialog(null, "You pressed X\n"+"Pressed value is = "+n);
        }

OR

int n = JOptionPane.showConfirmDialog(null, "Yes No Cancel", "YesNoCancel", JOptionPane.YES_NO_CANCEL_OPTION);
    switch (n) {
        case 0:
            JOptionPane.showConfirmDialog(null, "You pressed YES\n"+"Pressed value is = "+n);
            break;
        case 1:
            JOptionPane.showConfirmDialog(null, "You pressed NO\n"+"Pressed value is = "+n);
            break;
        case 2:
            JOptionPane.showConfirmDialog(null, "You pressed CANCEL\n"+"Pressed value is = "+n);
            break;
        case -1:
            JOptionPane.showConfirmDialog(null, "You pressed X\n"+"Pressed value is = "+n);
            break;
        default:
            break;
    }