Graphical user interfaces - Data Structures and Problem Solving Using Java - page 952

2. If graphics are used, make an extra class that extends JPanel . That

class must provide a paintComponent method and a public method that
can be used by the container to communicate to it. It may also need to
provide a constructor.

3. Pick a layout and issue a setLayout command.

4. Add components to the GUI using add .

5. Handle events. The simplest way to do this is to use a JButton and trap

the button push with actionPerformed .

Once a GUI class is written, an application defines a class that extends
CloseableFrame with a main routine. The main routine simply creates an
instance of this extended frame class, places the GUI panel inside the frame's
content pane, and issues a pack command and a show command for the frame.

B.3.6 is this everything i need to
know about swing?

What we have described so far will work well for toy user interfaces and is an
improvement over console-based applications. But there are significant com-
plications that a professional applications programmer would have to deal
with.
It is rare that the layout manager will make you happy. Often you need to
tinker by adding additional subpanels. To help out, Swing defines elements
such as spacers, struts, and so on that allow you to position elements more
precisely, along with elaborate layout managers. Using these elements is quite
challenging.
Other Swing components include sliders, progress bars, scrolling (which
can be added to any JComponent ), password textfields, file choosers, option
panes and dialog boxes, tree structures (such as what you see in File Manager
on Windows systems), tables, and on and on. Image acquisition and display is
also supported by Swing. Additionally, one often needs to know about fonts,
colors, and the screen environment that one is working in.
Additionally, there is the important issue of what happens if an event
occurs while you are in an event handler. It turns out that events are queued.
However, if you get trapped in an event handler for a long time, your applica-
tion can appear unresponsive; we've all seen this in application code. For
instance, if the button-handling code has an infinite loop, you will not be able
to close a window. To solve this problem, typically programmers use a tech-
nique known as multithreading , which opens up a whole new can of worms.