actionlistener and restricting size of button

[Manjunath A.S]

i have few queries using swing?

1. can somebody tell me how do i restrict the size of the button that we create using swing?
2. how to place a particular button at a desired location?
3. how to check whether the user has typed 10 characters or 20 and so on?
4. how to create password window such that it shouldnt display anything when the user types password . also, how to use action listener when user completes typing password and presses enter?

[Mathias Nilsson]

Hi!

The restriction on the JButton has to do with the Layoutmanager you are using.
You can use the inherited method from JComponent setPerferredSize() to set the size.

If you meen by password that the user only will see ***** when he/she types you can use the JPasswordField. Package javax.swing

to check the length you can do it by checking the .length() on the text. If you want to alert the user then add a keypressListener and check the length in there. See java.awt.event

To add a ActionListener to a button you can try the following

ActionListener listener = new ActionListener(){
  public void actionPerformed( ActionEvent e ){
    // do the code here
  }
};
 
// add the listener to a button
 
JButton b = new JButton( "Click me!" );
b.addActionListener( listener );