I've recently started learning and
exploring the basics of GUI programming in
Java.
Having been programming for a while I have
only done backend work or work and as a result the closest I've gotten to user
interfaces is the command console (embarrassing I
know).
I'm using Swing and as far as
I can gather that means by extension I am also using
AWT.
My question is based on this piece of
code:
java.awt.EventQueue.invokeLater(new
Runnable() {
public void run() {
new
frame.setVisible(true);
}
}
);
I have
been researching this for a while as I wanted to fully understand this strange piece of
code and have come across the term 'Event-Dispatching Thread' multiple times. Correct me
if I'm wrong but as I understand it; it has to do with using multiple threads and how
Java Swing interprets those threads. I gather as well that the above code is used to
make sure all the threads are 'safe' before it creates the window, hence the
invokeLater?
I have read
that:
"You can
only call methods that operate on the frame from the Event-Dispatching
Thread"
and
that only under certain circumstances can you call methods that operate on the frame
from the main method.
Can
somebody please clarify to me what exactly the Event-Dispatching Thread
is?
How it relates
to multiple threads of execution and how those threads are not safe to be called from
the main method? Also why do we need this
invokeLater?
Can we
not just create the window as any other
object?
I've hit a bit of a road
block in my research as I'm not grasping these relations and
ideas.
A side note is that I like to
base my knowledge on in-depth understanding as I believe this leads to the best overall
outcome and as a result the best programs. If I understand in-depth how something works
then you can use the tips and tweaks effectively rather than just parroting them back in
to code, so please don't be afraid to give me some extra in-depth explanations and
broaden my knowledge.
Thank
you.
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