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Answers: Learning Swing by Example

### Questions

> Question 1: On what thread should GUIs be created, to guarantee thread safety?
> Answer 1: The event-dispatching thread.

> Question 2: Why should you be careful to minimize the time spent in event-handler code?
> Answer 2: Painting code also executes in the event-dispatching thread. Therefore, event-handling code should execute quickly so that the program's GUI stays responsive. If an event takes too long to execute, the GUI will freeze — that is, it won't repaint or respond to mouse clicks.

> Question 3: What is the purpose of the `setLabelFor` method?
> Answer 3: The `setLabelFor` method provides a hint to assistive technologies, such as screen readers, that the label describes a particular component.

> Question 4: What is the content pane?
> Answer 4: The content pane is the main container in `JApplet`, `JDialog`, and `JFrame` objects.

> Question 5: Describe the three code segments that must be implemented for an event handler.
> Answer 5:

> 1. In the declaration for the event handler class, one line of code specifies that the class either implements a listener interface or extends a class that implements a listener interface. For example:

>    >     public class MyClass implements ActionListener {

> 2. Another line of code registers an instance of the event handler class as a listener on one or more components. For example:

>    >     someComponent.addActionListener(instanceOfMyClass);

> 3. The event handler class has code that implements the methods in the listener interface. For example:

>    >     public void actionPerformed(ActionEvent e) {
>    >         ...//code that reacts to the action...
>    >     }

> Question 6: Which text component is best suited for controlling the format of a single line of user-entered text?
> Answer 6: `JFormattedTextField`

> Question 7: What is lazy image loading and why would you use it?
> Answer 7: With lazy image loading you only load images as they are needed. By loading images as needed, you reduce the application's initialization time; however, the downside is that the user may notice a delay as an image is loaded.

### Exercises

> Question 1: Write the code that creates a label displaying the following text, with the italics and font size as shown in this screenshot:

> Answer 1: Here's the code that sets the label text:

> >     private static String labelText =
> >             "<html>The <em>last</em%gt; word is <font size=+2>big</font>.</html>";

> For the full code, see Test1 .

> Question 2: Convert the `LunarPhases` example to use radio buttons instead of a combo box.
> Answer 2: See `LunarPhasesRB`.

> Question 3: Add a Show Dialog check box to the `VoteDialog` example so that the dialogs are shown only if this check box is selected.
> Answer 3:

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