Soo created a timer using extending timertask.
label_1.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent arg0) {
label_1.setVisible(false);
label_2.setVisible(true);
timer.purge();
class MyTimeTask extends TimerTask
{
public void run(){
genReelNumbers();
laa++;
if(laa==50){
timer.cancel();
timer.purge();
laa=0;
label_1.setVisible(true);
label_2.setVisible(false);}}}
timer.purge();
timer.schedule(new MyTimeTask(), 0, 50);}});
But im getting a error with the timer already canceled! As you can see i already tried to use the purge(), soo it cancels the "canceled" timers (dont know if that does make any sence). I want to use this timer each time that i press on the label! Any ideas?
First and foremost, this looks to be a Swing application, and if so, you shouldn't be using java.util.Timer and java.util.TimerTask since Swing is single-threaded, and the two classes above create a new thread or threads to achieve their actions, meaning that important code that should be called on the Swing event thread will not be called on this thread. This this risks causing pernicious intermittent and hard to debug threading exceptions to be thrown. Instead use a javax.swing.Timer. Then to stop this timer, simply call stop() on it, and to restart it, simply call start() on it. For more on this, please read: How To Use Swing Timers.
For example, I'm not 100% sure what you're code is supposed to be doing, but it could look something like:
// warning: code not compile- nor run-tested
label_1.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent arg0) {
label_1.setVisible(false);
label_2.setVisible(true);
// assuming a javax.swing.Timer field named timer
if (timer != null && timer.isRunning()) {
// if the timer is not null and it's running, stop it:
timer.stop();
}
// TIMER_DELAY is an int constant that specifies the delay between "ticks"
timer = new Timer(TIMER_DELAY, new ActionListener() {
#Override // this method will be called repeatedly, every TIMER_DELAY msecs
public void actionPerformed(ActionEvent e) {
genReelNumbers();
laa++;
if(laa==50){
timer.stop();
// timer.purge();
laa=0;
label_1.setVisible(true);
label_2.setVisible(false);
}
}
});
timer.start();
}
});
after canceling the timer you have no other choice than creating a new object....
I followed the #Hovercraft advice and changed to javax.swing.Timer
It turned out like this:
//The variable "taxa" is the amount of times that i want it to do the task
javax.swing.Timer time1 = new javax.swing.Timer(taxa, new ActionListener() {
public void actionPerformed(ActionEvent e) {
genReelNumbers();
}
});
//starts the timer
time1.start();
//New timertask
TimerTask tt = new TimerTask() {
#Override
public void run() {
//stops the timer
time1.stop();
label_2.setVisible(false);
label_1.setVisible(true);
verificarodas();
}
};
Timer time = new Timer(true);
// the 2000 is how long i want to do the task's
//if i changed to 3000 it would take 3 seconds (remember it has to be a value on miliseconds) to do the 15 times, and soo on
time.schedule(tt, 2000);
Related
I am trying to do the following: click a button, button disappears for 2 seconds, text appears for 2 seconds and after those 2 seconds the visibility is reversed. So far I have done this:
btnScan.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
txtScanning.setVisible(true);
btnScan.setVisible(false);
try {
Thread.sleep(2000); //1000 milliseconds is one second.
} catch(InterruptedException ex) {
Thread.currentThread().interrupt();
}
}
btnScan.setVisible(true);
}
});
and the result is that as soon as I click the btnScan, the whole program freezes for 2 seconds before doing anything. How do I add the delay at the correct order?
You should not call sleep method in your code that dispatches the event. All the work related UI is handled by EDT(Event Dispatch Thread) and a sleep method will cause it to freeze and hence your Swing application will freeze.
To overcome it you should use a Timer. Run the timer and execute the UI manipulation using SwingUtilities.invokeLater so that it is handled by EDT.
import java.util.Timer;
// make it a member variable
Timer timer = new Timer();
........
public void actionPerformed(java.awt.event.ActionEvent evt) {
button.setVisible(false);
timer.schedule(new TimerTask() {
#Override
public void run() {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
button.setVisible(true);
}
});
}
}, 2000);
}
Currently in your code, you are causing the EDT (event dispatcher thread) to pause with the invocation of Thread.sleep
Performing any long running tasks in the EDT will cause your UI to freeze.
To achieve what you desire, use a SwingWorker thread to perform your actions
This might help: http://docs.oracle.com/javase/tutorial/uiswing/concurrency/worker.html
Swing is a single threaded environment, anything that blocks this thread will prevent it from processing new events, including repaint requests.
Swing is also not thread safe, meaning img you should never create or update the UI from outside the context of the EDT.
In this case you can use a Swing Timer to trigger a callback to occur at some time in the future which (the notification) will be executed within the context of the EDT, making it safe to update the UI with
Take a look at Concurrency in Swing and How to us Swing Timers for more details
Making use of Swing timer, you can do something like this:
btnScan.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
txtScanning.setVisible(true);
btnScan.setVisible(false);
Timer timer = new Timer(2000, new ActionListener() {
#Override
public void actionPerformed(ActionEvent acv) {
btnScan.setVisible(true);
txtScanning.setVisible(false);
}
});
// setRepeats(false) to make the timer stop after sending the first event
timer.setRepeats(false);
timer.start();
}
});
I'm having problem with Android timer's scheduleAtFixedRate option.
Timer timer = new Timer();
TimerTask myTimerTask = new TimerTask() {
public void run() {
...
}
};
timer.scheduleAtFixedRate(myTimerTask, 0, 5000);
This snippet is doing bad things for me. It's executed in the service so every time method is called timer creates a new thread and executes the same code while the old thread is still running; that creates performance problems. I need to run the code in the run() method every 5 seconds but I want the old task to be canceled. Is there any way to handle this problem ?
You can use the timer.cancel() to stop the timer.
For example, I had an end button to finish the timer early:
finishEarlyButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
timer.cancel();
}
});
in main if the following code is used
Timer timer = new Timer(200, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("boo");
}
});
timer.start();
Thread.sleep(3000);
boo will be printed every 200 milliseconds as expected.
While
Timer timer = new Timer(200, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("boo");
}
});
timer.start();
nothing will be output!
Presumably the code you're showing is in main(). When main() returns, the program exits before the timer thread has a chance to get going. The sleep gives the JVM enough time to create the other thread, which then allows the JVM to keep running.
Could it be that the Thread.sleep is on the main thread and that the reason nothing is printed in the second case is that the main thread goes away and the program exits?
Is that the complete program (is that the only code in your main method)? If yes, then in the second case the program ends before the timer goes off, so it won't print anything, because the program is finished almost immediately.
1) this code wokrs and in all cases is correct
Timer timer = new Timer(200, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
System.out.println("boo");
}
});
timer.start();
you have to check if javax.swing.Timer#setRepeats() have true value (default value), if isn't changed, otherwise you have a code that block Event Dispatch Thread, thenafter Swing's Timer too,
2) don't use Thread.sleep(int) during EDT, and untill Sleep ended caused this code block for EDT,
Problem, I can only execute my timer once. I know its because I called the function timer2.cancel(); and timer1.cancel(); :: Cancel being "Never run this ever again". I need a replacement function, one that actually stops a timer, but can be started back up again when I reschedule it. How do I go about doing that?
public void actionPerformed (ActionEvent e){
if (e.getSource()==jbtStart)
{
System.out.println("Start is pressed");
timer2.cancel();
timer1.schedule(new Task(), 0, delay);
}
else if (e.getSource()==jbtStop)
{
System.out.println("Stop is pressed");
timer1.cancel();
timer2.schedule(new Task2(), 0, delay);
}
Why not just create a new Timer at that point? Either that, or keep hold of the TimerTask as well as the timer, and cancel that instead of the timer itself.
As a third possible alternative, have a single timer task and a single timer, but make the timer task aware of what it's meant to do at any point - it looks like you're effectively toggling what you want to do each time the timer ticks. You could always keep two separate classes to separate the logical functionality, and then have a "wrapper" task which allows you to replace what behaviour is executed on each run.
I would cancel the TimerTasks instead of the Timers (and I would use only one Timer).
UPDATE:
private Task task1;
private Task2 task2;
public void actionPerformed (ActionEvent e){
if (e.getSource()==jbtStart)
{
System.out.println("Start is pressed");
if (task2 != null) {
task2.cancel();
}
task1 = new Task();
timer.schedule(task1, 0, delay);
}
else if (e.getSource()==jbtStop)
{
System.out.println("Stop is pressed");
if (task1 != null) {
task1.cancel();
}
task2 = new Task2();
timer.schedule(task2, 0, delay);
}
So in this chunk of code:
//Actions performed when an event occurs.
public void actionPerformed(ActionEvent event)
{
String command = event.getActionCommand();
//If btnConvertDocuments is clicked, the FileConverter method is called and the button is then disabled [so as to prevent duplicates].
if (command.equals("w"))
{
new Thread(new Runnable()
{
public void run()
{
FileConverter fc = new FileConverter();
}
}).start();
btnConvertDocuments.setEnabled(false);
//Validation message ensuring completion of the step.
JOptionPane.showMessageDialog(this, "Step 1 Complete!", "Validation", JOptionPane.INFORMATION_MESSAGE);
}
It seems like the message dialog window pop-ups way too fast, before the FileConverter method isn't even finished being called. I was wondering if the placement of JOptionPane was correct, or if there was a way to delay a message until the method finished processing?
You can use the SwingWorker.
Have a look here, java tutorial.
SwingWorker worker = new SwingWorker<Void, Void>() {
#Override
public Void doInBackground() {
FileConverter fc = new FileConverter();
return null;
}
#Override
public void done() {
JOptionPane.showMessageDialog(this, "Step 1 Complete!", "Validation", JOptionPane.INFORMATION_MESSAGE);
}
};
You should use a Swing Timer with a delay, instead of using your own Thread and Runnable for this.
You can use Swing timers in two ways:
To perform a task once, after a delay.
For example, the tool tip manager uses Swing timers to determine when to show a tool tip and when to hide it.
To perform a task repeatedly.
For example, you might perform animation or update a component that displays progress toward a goal.
An example from the documentation:
int delay = 1000; //milliseconds
ActionListener taskPerformer = new ActionListener() {
public void actionPerformed(ActionEvent evt) {
//...Perform a task...
}
};
Timer myTimer = new Timer(delay, taskPerformer);
myTimer.setRepeats(false);
myTimer.start();