This post is related to my last post.The block of code changes the text to desired color after desired time.
however, now I want to change the color of a perticular word such that each letter gets the equal time.EG if "hello" have been given a time of 1000 milliseconds (have 5 letters) then 'h''e''l''l''o' each letter should get 1000/5 milliseconds i.e 200 milliseconds each.
I implemented swing timer for this :
public Reminder() {
a[0]=2000;
a[1]=1000;
a[2]=3000;
a[3]=5000;
a[4]=3000;
ActionListener actionListener = new ActionListener() {
public void actionPerformed(ActionEvent actionEvent) {
point =point +arr[i].length();
i++;
doc.setCharacterAttributes(0,point+1, textpane.getStyle("Red"), true);
timer.setDelay(a[i]);
}
};
timer = new Timer(a[i], actionListener);
timer.setInitialDelay(0);
timer.start();
For this to happen, shoud I use another Timer inside the actionListener to give further timings to a perticular letter?Or should I first break the time by .length()
and then use the timer?I cannot decide a better way.Any ideas?
You should never need more than one timer. Since you know ahead of time exactly when everything should happen, just calculate those times, put them in a list (sorted by time) and execute each one.
public colorize(int offset, int length) {
long triggerTime[] = new long[length];
long startTime = System.currentTimeMillis();
for (int i=0; i<length; i++) {
triggerTime[i] = startTime + (1000*i)/length;
}
for (int i=0; i<length; i++) {
//just wait for the next time to occur
Thread.sleep(triggerTime[i]-System.currentTimeMillis());
doc.setCharacterAttributes(offset, i+1, textpane.getStyle("Red"), true);
}
}
This may strike you as very pedestrian because it does not use a TimerTask object, but it is effective, efficient, and easy to debug. You simplty call this method on whatever thread you want, and it occupies the entire thread, and the word will be colorized at a rate such it is completed in 1 second.
You could, if you don't have a thread handy, make a timer that calls this, but the only reason for that is to access a thread. The real point is: don't set up multiple timers, just make an array of time values. After one event is satisfied, set to delay until the next time. You never need multiple timers.
It would be a little cleaner if you made an object that represented the coloring of a character (or whatever action you want) and you put together a collection of these actions. Then sort the entire collection by time they are to go off. The loop above would walk through the collection, waiting until the time for the action arrives, and then executing it. Another advantage of this approach is that you could clear the collection and that would terminate the loop.
See the discussion of the overuse of timers on my website to understand why this is bad.
Related
I'm using Java within a Processing project. I'm trying to make a delay that doesn't stop the program, but stops only a given block of code. That "processing" block of code could for example add 1 to a variable, then wait one second and then add 1 again. The problem is that delay() (see reference) stops the whole program and Thread.sleep() doesn't work in a Processing project.
You should not use delay() or Thread.sleep() in Processing unless you're already using your own threads. Don't use it on the default Processing thread (so don't use it in any of the Processing functions).
Instead, use the frameCount variable or the millis() function to get the time that your event starts, and then check that against the current time to determine when to stop the event.
Here's an example that shows a circle for 5 seconds whenever the user clicks:
int clickTime = 0;
boolean showCircle = false;
void draw(){
background(64);
if(showCircle){
ellipse(width/2, height/2, width, height);
if(clickTime + 5*1000 < millis()){
showCircle = false;
}
}
}
void mousePressed(){
clickTime = millis();
showCircle = true;
}
Side note: please try to use proper punctuation when you type. Right now your question is just one long run-on sentence, which makes it very hard to read.
I have two threads in my ChessGame and I want to implement time control:
Turn of first player: second_thread.stop(), first_thread.run();
counterOfSteps++;
Turn of second player: first_thread.stop(), second_thread.run();
counterOfSteps++;
I have founded many information about Timer but I need Threads.Second thread the same.
There is my code of first thread and it doesn't work because time isn't stopped (System.currentTimeMillis)
first = new Thread() {
#Override
public void run() {
final long time = System.currentTimeMillis();
final long duration = 10800000; //3 hours
while (true) {
try {
Thread.sleep(100);
if (counterOfSteps % 2 == 0) {
System.out.println("Time" + ((duration - (System.currentTimeMillis() - time)) / 1000) % 60);
}
} catch (InterruptedException ex) {
LOG.log(Level.SEVERE, "Unexpected interrupt", ex);
}
}
}
};
How to solve this problem?
Update:
I don't use .stop(). I wrote is for example how to realize.
I have founded many information about Timer but I need Threads.
No. If all you are trying to do is implement a chess clock, then you don't need threads for that. A Timer task that wakes up every second (or every 1/10 second) can;
look at whose turn it is (e.g., counterOfSteps % 2),
compute how much time that player has used, and
Update the appropriate text box in the GUI.
To compute how much time, it'll need to know three things;
What time it is now (e.g., System.currentTimeMillis()),
What time it was when the current turn started, and
How much time the player already had on the clock when the current turn started.
There is no way to pause the system clock (i.e., System.currentTimeMillis()), but that's not a problem. If you sample the clock at the start of each turn, then you can compute the duration of the current turn as System.currentTimeMillis() minus the start time.
I used this example for my quiz, i have 10sec do answer on question this timer decrease int t every 1sec, and set how many times left in some JLabel. You can make 2 object of Timer, first object for first player and second object for second player. You can stop timer when someone finish the move and start second timer...
int t=10
lb2=new JLabel(t);
tim=new Timer(1000,new ActionListener(){
#Override
public void actionPerformed(ActionEvent e){
if(t>0){
t--;
lb2.setText(String.valueOf(t));
}else{
tim.stop();
JOptionPane.showMessageDialog(null, "Time is up");
}
}
});
}
I'm trying to implement a countdown timer into a pre-existing public class and I have a few questions.
An overview: I want to have a timer within a program that counts down from 60 (seconds) once the program is initialized.
If the timer reaches zero, the program quits.
If the user meets certain parameters within the 60 second time frame, the timer resets to 60, presents a new set of parameters, and begins the countdown again. It should be able to do this an infinite number of times, until the user fails to meet parameters within 60 seconds.
There will also be some sort of (TBD) GUI representation of the timer, most likely either numerical countdown or JProgressBar.
I'm semi-new (~3 months) to programming, self-taught, and still learning lots (so be gentle) :)
My questions are:
What is the best way to implement this?
I'm assuming this needs to run in a thread?
Will the timer be easily configurable? (not important, just interesting)
Thanks for your help. If you need to see code, I can find some.
EDIT: Just for some clarification/context:
This is for a timed racing video game I'm working on to develop my skills as a programmer. The idea is that a player has 60 seconds to complete a lap. If the player completes a successful lap, the timer resets to 60 seconds and the track changes to be slightly more difficult. The game runs until the player is unable to complete a lap in 60 seconds due to the difficulty. The game records the number of laps as a high score, and asks to player if they would like to try again.
If I were you, I'd use:
an AtomicInteger variable which would keep the current countdown value;
a timer thread that would wake up every 1s and decrementAndGet() the variable, comparing the result to zero and terminating the app if the result is zero;
(possibly) a thread that would also wake up every 1s to repaint the GUI -- the best approach here depends on your GUI framework.
Finally, whenever you need to reset the count back to 60s, you just call set(newValue) from any thread.
The timer thread's run() method could be as simple as:
for (;;) {
if (counter.decrementAndGet() <= 0) {
// TODO: exit the app
}
Thread.sleep(1000);
}
I think it's much easier to get this right than trying to manage multiple Timer objects.
The best way to impliment timer in your application is using some sheduler frameworks like Quartz
You could use java.util.Timer to schedule an execution of a method and then cancel it if the requirements is met.
Like this:
timer = new Timer();
timer.schedule(new Task(), 60 * 1000);
And then make a class like this to handle the timerschedule:
class Task extends TimerTask {
public void run() {
System.exit(0);
}
}
If the requirements is met, then do this to stop it from executing:
timer.cancel();
If you need to update your GUI better to use SwingWorker http://en.wikipedia.org/wiki/SwingWorker
I would write something like this:
SwingWorker<String, Integer> timer = new SwingWorker<String, Integer>() {
Integer timer=60;
#Override
protected String doInBackground() throws Exception {
//update guiModel
//label.setText(timer.toString());
while(timer>0){
Thread.sleep(1000);
timer--;
}
return null;
}
#Override
public void done(){
System.exit(0);
}
};
JButton restart = new JButton(){
{
addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
timer.cancel(true);
timer.execute();
}
});
}
};
In our class we are making a game. The user has to Guess words and stuff. I don't think info about the game is needed to answer my question/problem.
Ok so what I am trying to do is to give the user a time limit in which they have to guess the word. Something like 15 seconds. If the user does not guess the word in 15 seconds they lose a turn.
Problems:
We didn't learn how to use timers. I experiment with timers and stuff. I can get a timer to count down from 15.
I can't check the current time while waiting for the user to input a guess.
I don't know how to bypass Stdin.readString() and make the program check the time.
Thanks.
Well, you can use the Scanner class to gather input from the user.
You may want to avoid timers if you don't know what threading is yet, but if you do want to try, you might be interested looking into the TimerTask & Timer classes.
While you may already know, you can get time from the System class, like currentTimeMillis
You have a few options. As you said, your program is waiting for input and hence that thread is busy. What you can do is create a separate thread, pass your timer to that thread and have it check the timer. Perhaps something like the following:
public class TimerChecker implements Runnable {
private Timer timer;
public TimerChecker(Timer timer) { this.timer = timer; }
#Override
public void run() {
// implement logic here
}
}
Which you can have invoked in a new thread using:
Timer timer = ...
new Thread(new TimerChecker(timer)).start();
// Now you are free to perform your blocking operation in the current thread
Stdin.readString();
One way to do this is, well to a run a separate thread object for the timer... this thread shall handle the updating of the time and would then trigger a certain event when the time of the player runs out...
or more like, implementing a counter in a separate thread whose increments are triggered by time-step, in this case, in seconds, you can do this by calling sleep()..
the timer thread object shall maintain a variable which keeps track of the current time..
on the main method of your program, you shall continue to check the value of this variable, as a pre-condition of your main loop perhaps,
the idea is there i think, just a thought!
pseudocode
class Timer extends Thread{
int current_time = 0;
public void run(){
sleep(1000);
current_time += 1;
}
public void synchronized getCurTime(){
return current_time;
}
}
class Game{
public Game(){
Timer timer = new Timer();
timer.start();
while (timer.getCurTime() <16){
//get the guess of the user
//checks if it's correct
// if it is correct, output you win and break!
}
//time runs out
}
}
How about an Event driven architecture with Java eventing library?
Example of events with conditions.
I'm trying to write a blackberry app that is basically a stopwatch, and displays lap times. First, I'm not sure I'm implementing the stopwatch functionality in the most optimal way. I have a LabelField (_myLabel) that displays the 'clock' - starting at 00:00. Then you hit the start button and every second the _myLabel field gets updated with how many seconds have past since the last update (should only ever increment by 1, but sometimes there is a delay and it will skip a number). I just can't think of a different way to do it - and I am new to GUI development and threads so I guess that's why.
EDIT: Here is what calls the stopwatch:
_timer = new Timer();
_timer.schedule(new MyTimerTask(), 250, 250);
And here is the TimerTask:
class MyTimerTask extends TimerTask {
long currentTime;
long startTime = System.currentTimeMillis();
public void run() {
synchronized (Application.getEventLock()) {
currentTime = System.currentTimeMillis();
long diff = currentTime - startTime;
long min = diff / 60000;
long sec = (diff % 60000) / 1000;
String minStr = new Long(min).toString();
String secStr = new Long(sec).toString();
if (min < 10)
minStr = "0" + minStr;
if (sec < 10)
secStr = "0" + secStr;
_myLabel.setText(minStr + ":" + secStr);
timerDisplay.deleteAll();
timerDisplay.add(_timerLabel);
}
}
}
Anyway when you stop the stopwatch it updates a historical table of lap time data. When this list gets long, the timer starts to degrade. If you try to scroll, then it gets really bad.
Is there a better way to implement my stopwatch?
Here are a few tips:
keep track of the last "sec" value used to update the label, and exit from the run loop immediately if the newly-calculated "sec" value is the same - otherwise you're needlessly refreshing the UI with the same values which slows everything down
remove the synchronization in your run loop and just put the code that modifies the UI (setText call) in a UiApplication.getUiApplication.invokeLater() call (using an anonymous Runnable)
don't delete the re-add the label from the screen or maanger, you just need to call setText() and it should update - if it doesn't update then call invalidate() on the field and it will be redrawn
now that you've optimized your code and minimized the amount of actual UI drawing, it's safe to set the timertask interval to a lower value, such as 50ms, so that you have a smoother timer update
The most important thing to remember in making a fast UI is to only update the UI when you need to, and only update the fields that need to change. If you're calling methods like deleteAll() you're going to end up having the entire screen or manager refresh which is really really slow.