The JavaTM Tutorial

| Start of Tutorial > Start of Trail > Start of Lesson | Search Feedback Form

Trail: Creating a GUI with JFC/Swing
Lesson: Using Swing Components

## Answers: Using Swing Components

> Use the information in this lesson and the component how-to sections to help you complete these questions and exercises.

### Questions

> Question 1: Find the component that best fits each of the following needs. Write down both the component’s common name (such as “frame”) and find the component's how-to page online. [Hint: You can use A Visual Index to the Swing Components to help you answer this question.]

> > Question 1a: A component that lets the user pick a color.
> > Answer 1a: color chooser
> > Question 1b: A component that displays an icon, but that doesn’t react to user clicks.
> > Answer 1b: label
> > Question 1c: A component that looks like a button and that, when pressed, brings up a menu of items for the user to choose from.
> > Answer 1c: uneditable combo box
> > Question 1d: A container that looks like a frame, but that appears (usually with other, similar containers) within a real frame.
> > Answer 1d: internal frame
> > Question 1e: A container that lets the user determine how two components share a limited amount of space.
> > Answer 1e: split pane

> Question 2: Which method do you use to add a menu bar to a top-level container such as a `JFrame`?
> Answer 2: `setJMenuBar`

> Question 3: Which method do you use to specify the default button for a top-level container such as a `JFrame` or `JDialog`?
> Answer 3: `JRootPane`'s `setDefaultButton` method. (You get the top-level container's root pane using the `getRootPane` method defined by the `RootPaneContainer` interface, which every top-level container implements.)

> Question 4: Which method do you use to enable and disable components such as `JButton`s? What class is it defined in?
> Answer 4: `setEnabled`, which is defined in the `Component` class

> Question 5a: Which Swing components use `ListSelectionModel`? [Hint: The “Use” link at the top of the specification for each interface and class takes you to a page showing where in the API that interface or class is referenced.]
> Answer 5a: `JList` and `JTable`

> > Question 5b: Do those components use any other models to handle other aspects of the components’ state? If so, list the other models’ types.
> > Answer 5b: `JList` also uses a `ListModel`, which holds the list's data. `JTable` uses a `TableModel` to hold its data and a `TableColumnModel` to manage the table's columns.

> Question 6: Which type of model holds a text component’s content?
> Answer 6: `Document`

### Exercises

> Exercise 1. Implement a program with a GUI that looks like the one shown below. Put the main method in a class named `MyDemo1`.

> Answer 1: See `MyDemo1.java`. Here's the code that adds the bold, italicized text:

> >     JLabel label = new JLabel("My Demo");
> >     frame.getContentPane().add(BorderLayout.CENTER, label);
> >     label.setFont(label.getFont().deriveFont(Font.ITALIC | Font.BOLD));
> >     label.setHorizontalAlignment(JLabel.CENTER)

> Exercise 2. Make a copy of `MyDemo1.java` named `MyDemo2.java`. Add a menu bar to `MyDemo2`.
> Answer 2: See `MyDemo2.java`. The menu bar can be implemented with this code:

> >     JMenu menu = new JMenu("Menu");
> >     JMenuBar mb = new JMenuBar();
> >     mb.add(menu);
> >     frame.setJMenuBar(mb);

> Exercise 3. Copy `MyDemo1.java` to `MyDemo3.java`. Add a button (`JButton`) to `MyDemo3.java`. Make it the default button.
> Answer 3: See `MyDemo3.java`. Here's the code that adds the button and makes it the default button:

> >     JButton b = new JButton("A button");
> >     frame.getContentPane().add(BorderLayout.PAGE_END, b);
> >     frame.getRootPane().setDefaultButton(b);

| Start of Tutorial > Start of Trail > Start of Lesson | Search Feedback Form

Copyright 1995-2004 Sun Microsystems, Inc. All rights reserved.