UPDATE
This answer is updated, because @uckelman pointed me out that, with the condition run = true, the stop button never breaks the while loop, because it's needed to change to run = false within the loop. Then I post a simple and alternative solution to this logic problem, to schedule a task repeatedly with a timer. For details, please check this SO question.
About the events for the buttons: if you have two buttons, one to start a loop and one to end the loop, just try this code:
class CalcButtonListener implements ActionListener{
private boolean run = true;
private java.util.Timer timer = new java.util.Timer();
private JButton start_loop, end_loop;
//here the buttons initialization
@Override
public void actionPerformed(ActionEvent ae){
if(ae.getSource()==start_loop){
java.util.TimerTask task = new java.util.TimerTask() {
@Override
public void run() {
doStuff();
}
};
timer.schedule(task, java.util.Calendar.getInstance().getTime(), 500);//here the '500' means the time, 500 ms,
the task is repeatedly executed.
}
if(ae.getSource()==end_loop){
timer.cancel();//cancel the tasks scheduled
System.out.println("Task cancelled!");
}
}
private void doStuff(){
robot.mousePress(InputEvent.BUTTON1_MASK);
robot.mouseRelease(InputEvent.BUTTON1_MASK);
robot.delay(num.nextInt(max-min+1)+min);
}
}
Now, the task doStuff() is scheduled to be executed each 500 ms.
Other info about java.util.Timer and java.util.TimerTask.
About your problem:
The problem is I have another button to set the variable run to false
but once the first button is clicked, I can't click the second button
or the exit button at the top for that matter.
As in a previous question, and in this page, it's written this:
Swing's single-thread rule says that Swing components can only be
accessed by a single thread. This rule applies to both gets and sets,
and the single thread is known as the event-dispatch thread.
The single-thread rule is a good match for UI components because they
tend to be used in a single-threaded way anyway, with most actions
being initiated by the user. Furthermore, building thread safe
components is difficult and tedious: it's a good thing not to be doing
if it can be avoided. But for all its benefits, the single-thread rule
has far-reaching implications.
Swing components will generally not comply with the single-thread rule
unless all their events are sent and received on the event-dispatch
thread. For example, property-change events should be sent on the
event-dispatch thread, and model-change events should be received on
the event-dispatch thread.
For model-based components such as JTable and JTree, the single-thread
rule implies that the model itself can only be accessed by the
event-dispatch thread. For this reason, the model's methods must
execute quickly and should never block, or the entire user interface
will be unresponsive.
Then, if you develop your GUI using a single Thread, when a button event is executed, your GUI will freeze, waiting for the complete execution of the related button event. In your case, on a infinite loop, your GUI will always freezing.
My suggestion is to use, for your GUI, a SwingWorker, or extend the Thread class (then developing the GUI in a separate thread), or implement the Runnable interface. Another alternative is the using of a Timer from the javax.swing.Timer package.
You can read this old question of SO about SwingWorker: How do I use SwingWorker in Java?
A tutorial for SwingWorker : http://docs.oracle.com/javase/tutorial/uiswing/concurrency/worker.html
A tutorial to make a Thread : http://docs.oracle.com/javase/tutorial/essential/concurrency/
A question about Timer: Update JPanel and attributes in a gui, with a user-specified timer?
A tutorial about Timer: http://docs.oracle.com/javase/tutorial/uiswing/misc/timer.html
