Filenames are problematic, even if you don’t have to worry about cross-platform idiosyncrasies. Users forget filenames, mistype them, can’t remember the exact path to files they need, and more. The proper way to ask a user to select a file is to show them a list of the files in the current directory and get them to select from that list. You also need to allow them to navigate between directories, insert and remove floppy disks, mount network servers, and more.
Most graphical user interfaces (and not a few nongraphical ones)
provide standard widgets for selecting a file. In Java the
platform’s native file selector widget is exposed through the
java.awt.FileDialog class. Like many native
peer-based classes, however,
doesn’t behave exactly the same on all platforms. Therefore,
Swing (part of
the Java Foundation Classes) provides a pure Java implementation of a
file dialog, the
JFileChooser (and Swing in general)
has much more reliable cross-platform behavior.
I’m going to jump out of the
for a minute to pick up one file-related class from the
java.awt.FileDialog. File dialogs
are the standard open and save dialogs provided by the host GUI.
Users use them to pick a directory and a name under which to save a
file or to choose a file to open. The appearance varies from platform
to platform, but the intent is the same. Figure 13.1 shows a standard Save dialog on the Mac; ...