Library tutorials & articles
Programming with Swing
- Introduction
- JFrame and JPanel
- JButton and JLabel
- Component Layout
- MDI Applications
- GUI Look & Feel
- Listening for Action
Listening for Action
To Listen for an action like a mouse click or key press you use a Listener class.
There are several different types of Listener classes and this tutorial only talks about one
of them. To find out about the rest, consult a Swing Reference book like the one suggested
earlier. I like to use my Listeners as internal classes, so if you don't like that, TOO BAD!
We will be using ActionListener to learn how to use Listener objects.
ActionListener listens for a mouse click over a component. We will use it with a JButton to
do something when the JButton is clicked.
Here's the code to get a JFrame with a JPanel and a JButton:
JFrame frame = new JFrame("ActionListener Test");
JPanel panel = new JPanel();
JButton button1 = new JButton("Click Me!");
frame.setSize(256,256);
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
frame.getContentPane().add(panel);
panel.add(button1);
frame.pack();
frame.show();
Now we want to add a new ActionListener to JButton button1 :
button1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e1) {
// CODE TO RUN WHEN BUTTON CLICKED GOES HERE
}});
I realize that is probably a little simplistic, but we want to keep things
simplistic, don't we? Of course we do! So all this code does is make an internal class of
an ActionListener with it's method actionPerformed(ActionEvent e1) that runs when the
ActionListener detects (hears?) an action such as our button being clicked.
That's the basics of Action Listening, for more, go buy a good book. Get off the computer! Go do something, ride your bicycle, or something! A book is better for your eyes anyway than the RF Radiation coming from this screen! whew, there's my rant for this section.
Conclusion
I hope you had fun, Java is a neat language. More people should use it, as it has a large and usefull API and it runs on so many platforms. The interpreter has also gotten quite fast, so speed is no longer a reason for not using it.
I recommend going to http://java.sun.com/ and using the API docs, they are essential!
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Hello,
')
I want to add a closing button to the internal frame. I am not able to do it. Plz help.javascript:smilie('
confused
Hi.
I have an ChildFrame inside of an DesktopFrame. I want to insert a JButton into the ChildFrame. But this JButton turns out to be very tiny in that child frame. If I maximize the child frame, the button does not change size.
I used this a source for my codings:
http://www.rz.fhtw-berlin.de/hjp3/k100230.html
I only added a JButton into my chid frame, I used a GridBagLayout. button.setSize() does not seem to work in that child frame.
Would be very thankful, if anybody could help.
Burkhardt
jho....
just call your child frames as follows
public class MainFrame extends JFrame
{
ChildFrame1 child1;
public MainFrame()
{
final JDesktopPane desktop = new JDesktopPane();
getContentPane().add(desktop);
JMenuBar bar = new JMenuBar();
JMenu show = new JMenu("Show");
JMenuItem showchild1 = new JMenuItem("Show Child1");
//*******
// here this represents the MainFrame which can be passes as a message to the child frame.
child1 = new ChildFrame1(this);
//*******
desktop.add(child1);
child1.setVisible(true);
bar.add(show);
show.add(showchild1);
}
}
and in ChildFrame set the constructor as
MainFrame mainFrame;
ChildFrame(MainFrame mainFrame)
{
this.mainFrame = mainFrame;
}
actionPerformed in ChildFrame1() {
if(button clicked) {
ChilFrame2 childFrame2 = new ChildFrame2();
mainFrame.desktop.add(childFrame2);
this.dispose(); // or this.hide();
}
}
hope this code helps!
i have a JFrame named MainFrame which also uses JDesktoPane. I created 2 JInternalFrame class named ChildFrame1 and ChildFrame2. When I can click the menu on the mainframe, it shows the childframe1. I must load the Childframe2 on the desktopPane on the mainFrame by clicking a button inside the childframe1. How can I do this??? My problem is that the desktopPane becomes foreign to childFrame2 since it is another class. here is the sample prog...
public class MainFrame extends JFrame
{
ChildFrame1 child1 = new ChildFrame1();
public MainFrame()
{
final JDesktopPane desktop = new JDesktopPane();
getContentPane().add(desktop);
JMenuBar bar = new JMenuBar();
JMenu show = new JMenu("Show");
JMenuItem showchild1 = new JMenuItem("Show Child1");
desktop.add(child1);
child1.setVisible(true);
bar.add(show);
show.add(showchild1);
}
}
i still have another JInternalFrame class named childFrame2 but it will only be visible when i click a button in childFrame1 (child1).
how can i do this?????
i cannot use the jDESKTOPANE "desktop" because that class does not recognize the "desktop"
PLEASE HELP ME!!! I WILL DEFINITELY APPRECIATE YOUR HELP! THANKS A LOT!!!
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