Re: How do i know which superclass to inherit from...
On 02/17/2010 02:33 AM, Roedy Green wrote:
On Mon, 15 Feb 2010 07:53:08 -0500, Joshua Cranmer
<Pidgeot18@verizon.invalid> wrote, quoted or indirectly quoted someone
who said :
Traditionally, I make all of my custom panes extend JPanel; I can't
really think of a good case where JFrame needs to be extended: if I need
to make a powerful main window, I would likely just create a Main-ish
class that extends nothing and constructs the elaborate JFrame.
Can you please enumerate the reasons you would not extend a JFrame or
JPanel? It seems to me when you do, you nicely encapsulate, with
getters and private variables. What are the advantages of doing it the
other way?
Whenever I make a GUI, I've tended to think a lot more in terms of
bundles of components. In my most recent example, I essentially have a
StatisticsPane--a little window widget that contains displays of a set
of statistics. This is a pane, so it can be included somewhere in a
dialog, so it must be a JPanel (which is my reasoning for extending
JPanel: it's ultimately a JComponent, and JPanel is the most convenient
for me to extend).
Similarly, even the full, large window I have is merely a bundle of
components. Again, by that rationale, it can be contained in a
theoretically even larger program, so it shouldn't be a JFrame, it's a
JPanel. That's why I can't think of good times to extend JFrame: even
the large set of components is ultimately a bundle of components that
can be included elsewhere, perhaps having a related menu bar that may
need to be included as well.
I will admit that I probably am incorrectly extending JPanel to make all
of my panes (JComponent or even Container is probably better). I make my
panes components because I see them as atomic, indivisible visual areas
which are logically connected and can be independently used and
manipulated. I can use the StatisticsPane without having to use the
HistoryPane or ReviewPane, but I can't really use half of the ReviewPane
and still have a GUI that would make sense, for example.
--
Beware of bugs in the above code; I have only proved it correct, not
tried it. -- Donald E. Knuth