Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 203
  • Last Modified:

IF / ELSE: Changing Variable Values

Hello,
I'm getting NullPointerExceptions when i compile my program and I think I'm doing something wrong. So that I don't confuse you I'll give you the code before the exceptions began to happen and tell you what I need it to do. Here's a basic overview of the code: (much of the code has been excluded to keep things simple) (there's an explanation after the code)

class MailGUI extends JFrame
{
JCheckBox altserverCheckBox = new JCheckBox("Use an Alternate Server and/or port");

altserverCheckBox.addActionListener(new java.awt.event.ActionListener()
    {
      public void actionPerformed(ActionEvent e)
      {
        altsvrBox_actionPerformed(e);
      }
    });

void altsvrBox_actionPerformed(ActionEvent e)
{
serverTextField.setEnabled(altserverCheckBox.isSelected());
portTextField.setEnabled(altserverCheckBox.isSelected());
    if(altserverCheckBox.isSelected()){
    serverTextField.setBackground(bgwhite);
    portTextField.setBackground(bgwhite);}
    else{
    serverTextField.setBackground(bggrey);
    portTextField.setBackground(bggrey);}
}

}

class Message {
  String destination;

  public void setDestination(String dest) {
    destination = dest;
  }
  public String getDestination() {
    return destination;
  }
  public String getDestinationHost() {
    return destination.substring(destination.indexOf('@')+1);
  }
}

class MailTalk {
Message msg;

String destination = msg.getDestinationHost();
}


I want it to work so that if the checkbox defined in MailGui is checked it sets "destination" (String defined in MailTalk) to the text from a text field on the same GUI. If the box isn't checked I want it to be set to what it's currently bieng set to.

If this is confusing, don't be detured, just ask for clarification. Thanks.
0
m_morgan
Asked:
m_morgan
1 Solution
 
ykf2000Commented:
try modifying to this:

public String getDestinationHost() {
   return destination.equals("") ? "" : destination.substring(destination.indexOf('@')+1);
 }
0
 
OviCommented:
where do you declare portTextField and serverTextField ? I cannot see'it anyware. If you don't declare'it you should do'it. Any way, post the full exception
0
 
m_morganAuthor Commented:
Ovi: the exception is not the issue it's what to do instead. I did declare the two text fields as well as a bunch of other stuff that I left out.

ykf2000: that code compiles but when the function is called the program does nothing. Was I supposed to substitute certian things for names of parts of my program? Could you give me the code if I wanted it to decide where to go based on whether the: altserverCheckBox is checked. If it isn't checked I want it to return this: destination.substring(destination.indexOf('@')+1). If it is checked I want it to return the value of whatever is in the serverTextField.
0

Featured Post

Concerto Cloud for Software Providers & ISVs

Can Concerto Cloud Services help you focus on evolving your application offerings, while delivering the best cloud experience to your customers? From DevOps to revenue models and customer support, the answer is yes!

Learn how Concerto can help you.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now