In this code a while loop is supposed to check the time, and if the time is equal to 7 PM, then display a message box.
public void actionPerformed(ActionEvent arg0) {
Enable.setEnabled(false);
Date d = new Date();
int hrs = d.getHours();
int mins = d.getMinutes();
while((1 + 1) == 2) {
if(hrs == 19 && mins == 21) {
JOptionPane.showMessageDialog(frame,
"It's 7:21 PM!",
"Alerts",
JOptionPane.WARNING_MESSAGE);
System.exit(0);
break;
}
}
}
Pushing a button will do that code. If you push the button before it is 7 PM, the GUI will freeze (I don't care about that), and when it turns to 7 PM, it won't display the message box. If you click the button when it is 7 PM, then it will display the message box...
Instead of doing while((1 + 1) == 2) to get an infinite loop, you can just do: while(true) or for(;;)
And this question is unanswerable without any further information or code about your hrs and mins variables
You need to update hrs and mins in your loop otherwise the initialization of them, I assume at the time of pushing the button will always hold the time when the button was pushed.
This is why it works when pushed at 7pm but otherwise will not.
So do something like this
while(true) //Equivalent to what you had
{
if(hrs == 19 && mins == 00) {
JOptionPane.showMessageDialog(frame,
"It's 7:00 PM!",
"Time Alert",
JOptionPane.WARNING_MESSAGE);
System.exit(0);
break;
}
//Refresh your hrs and mins here
Calendar calendar = GregorianCalendar.getInstance(); // Probably dont really want to actually get an instance every time
hrs = calendar.get(Calendar.HOUR_OF_DAY);
mins = calendar.get(Calendar.MINUTE);
}
I'm thinking you're using 1+1=2 to have a continuous loop. you could use while(true){...} instead.
Also, the while loop wouldn't be practical for this case. There is an example on this page that does something similar (Alarm Clock): http://www.ibm.com/developerworks/java/library/j-schedule/index.html
this was their example. I updated it to suite your task.
public class AlarmClock {
private final Scheduler scheduler = new Scheduler();
private final SimpleDateFormat dateFormat =
new SimpleDateFormat("dd MMM yyyy HH:mm:ss.SSS");
private final int hourOfDay, minute, second;
public AlarmClock() {
this.hourOfDay = 19;
this.minute = 0;
this.second = 0;
}
public void start() {
scheduler.schedule(new SchedulerTask() {
public void run() {
soundAlarm();
}
private void soundAlarm() {
JOptionPane.showMessageDialog(frame,
"It's 7:00 PM!",
"Time Alert",
JOptionPane.WARNING_MESSAGE);
System.exit(0);
// Start a new thread to sound an alarm...
}
}, new DailyIterator(hourOfDay, minute, second));
}
public static void main(String[] args) {
AlarmClock alarmClock = new AlarmClock();
alarmClock.start();
}
}
Hope it helps.
Related
I have a custom timer that I'm keeping synced to the system clock. It's working fine for one minute intervals, but I also need it to sync to 36 second intervals (for updating fields when the user wants times displayed in decimal hours). Inside the Runnable I recalculate the adjustment (accurate enough for my needs) for the next minute, but can't find a way to conveniently deal with the different offsets needed for 36 seconds.
EDIT
private static class DecimalTimer extends TimerClass {
final int[] seconds = new int[101];
private boolean keepRunning = true;
private Runnable mRunnable;
#Override
void kill() {
keepRunning = false;
}
#Override
Runnable getRunnable() {
return mRunnable;
}
DecimalTimer() {
final int[] counter = new int[1];
for (int i = 0, j = 0; i < 3600; i += 36, j++) {
seconds[j] = i;
}
mRunnable = new Runnable() {
#Override
public void run() {
if (!keepRunning)
return;
final Calendar c = Calendar.getInstance();
int hourSeconds = c.get(Calendar.MINUTE) * 60 + c.get(Calendar.SECOND);
for (counter[0] = 0; counter[0] < 100; counter[0]++) {
if (seconds[counter[0]] > hourSeconds) {
c.add(Calendar.SECOND, seconds[counter[0]]);
break;
}
}
long adjustedDelay = (c.getTimeInMillis() - System.currentTimeMillis()) % 36000;
for (IntervalTimer listener : sListeners) {
listener.updateTime();
}
sHandler.postDelayed(this, adjustedDelay);
}
};
}
}
This edit fires every 36 seconds, but I need to get it to sync to 36 seconds on the clock (ie: 12:00:00, then 12:00:36 .. 12:01:12 .. 12:01:48)
Overthinking things as usual, this is what I came up with. It's accurate enough for what I need, but if anyone has an improvement for accuracy (It's a little off when it executes with 900ms or more) it'd be appreciated.
DecimalTimer() {
mRunnable = new Runnable() {
#Override
public void run() {
if (!keepRunning)
return;
final Calendar c = Calendar.getInstance();
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
do {
c.add(Calendar.SECOND, 36);
} while (c.getTimeInMillis() < System.currentTimeMillis());
long adjustedDelay = (c.getTimeInMillis() - System.currentTimeMillis()) % 36000;
for (IntervalTimer listener : sListeners) {
listener.updateTime();
}
sHandler.postDelayed(this, adjustedDelay);
}
};
}
Hello i am creating a timer in my app but i stuck in getting seconds left in day end from now (12.00 AM) my timer basically need to show time left for today 11-59 PM. I successfully created a timer function which takes inputs in seconds and then start countdown but i am unable to calculate remaining time of today in seconds
Below is my timer function
time = 30;
// Here i need time left for today end for example current time is 11.55 then remaining time is 5 minutes in seconds (300)
public void startTimer() {
new CountDownTimer(30000, 1000) {
public void onTick(long millisUntilFinished) {
textTimer.setText("0:"+checkDigit(time));
time--;
}
public void onFinish() {
textTimer.setText("try again");
}
}.start();
}
public String checkDigit(int number) {
return number <= 9 ? "0" + number : String.valueOf(number);
}
remaining time of today in seconds:
Calendar tomorrow = Calendar.getInstance();// creating a calendar for tomorrow at 12am
tomorrow.add(Calendar.DAY_OF_YEAR, 1);
tomorrow.set(Calendar.HOUR_OF_DAY, 0);
tomorrow.set(Calendar.MINUTE, 0);
tomorrow.set(Calendar.SECOND, 0);
tomorrow.set(Calendar.MILLISECOND, 0);
remainingSeconds = ( tomorrow.getTimeInMillis() - System.currentTimeMillis() ) / 1000
I'm trying to create a clock programm with customizable options but since I'm a beginner I'm running into some problems. I tried using the DigitalClock project but there's too many things in it for me right now
I looked into Timer and ScheduledExecuterService but I don't know how to use and where to place them.
I also tried to set a color to the background but the error was that it could be over ran.
How can I repeat the process in milliseconds, add a background and make the code lighter ?
public Clock() {
initComponents();
Calendar cal = new GregorianCalendar();
int second = cal.get(Calendar.SECOND);
int minute = cal.get(Calendar.MINUTE);
int hour = cal.get(Calendar.HOUR_OF_DAY);
/////////////////////////////////////////////////////////////
if (second < 10){
time.setText(" "+hour+": "+minute+":0"+second+"");
}
else if (minute < 10){
time.setText(" "+hour+":0"+minute+": "+second+"");
}
else if (hour < 10){
time.setText("0"+hour+": "+minute+": "+second+"");
}
else if (hour < 10 & minute < 10){
time.setText("0"+hour+":0 "+minute+": "+second+"");
}
else if (minute < 10 & second < 10){
time.setText(" "+hour+":0"+minute+":0"+second+"");
}
else if (hour < 10 & minute < 10 & second < 10){
time.setText("0"+hour+":0"+minute+":0"+second+"");
}
else {
time.setText(hour + " : " + minute + " : " + second+"");
}
////////////////////////////////////////////////////////////////
}
If you want to make it simple then you can simple do the following:
public static void main (String[] args) throws Exception
{
final SimpleDateFormat sf = new SimpleDateFormat("HH:mm:ss:SSS");
while(true) {
System.out.println(sf.format(new Date()));
Thread.sleep(1);
}
}
But this might miss a millisecond entry in between. For example, it might go directly to 310 after 308 and miss 309 in between. But since we are talking about 1/1000th of a second, in real life it is very unlikely to be noticed.
Your code will reduce to something like following:
public Clock() {
public static void main (String[] args) throws Exception {
initComponents();
final SimpleDateFormat sf = new SimpleDateFormat("HH:mm:ss:SSS");
while(true) {
time.setText = sf.format(new Date());
Thread.sleep(1);
}
}
}
final SimpleDateFormat sf = new SimpleDateFormat("HH:mm:ss:SSS");
Timer timer = new Timer();
timer.schedule(new TimerTask() {
public void run() {
System.out.println(sf.format(new Date()));
}
}, 0 , 1000000);
Will repeat in 1 ms.
So I'm starting to get really interested about Threads and how it works, Kinda amazing how it works but I just learned about it today and trying to make a program to work. So im trying to make a clock that gives me in a Jlabel a current clock which is right now and a Textfield where I enter the time by myself. so what I want to do is it should start by showing me the time, when pressing the button "Set time" it should change the time as I entered and go from there as a clock.
So my problem right now is that whenever I press the Set time now it changes for a second and then turn back to the current clock again. and I don't really know how to stop the first thread when pressing Set time (Which starts the second Thread)
However I think this is kinda simple but fun to work with,
EDIT: I Also found out that I will have a problem by counting when entering a own "clock". My code:
public Clock() {
initialize();
Thread1();
}
.......
JButton btnSetTime = new JButton("Set time");
btnSetTime.setBounds(474, 262, 89, 23);
frame.getContentPane().add(btnSetTime);
btnSetTime.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(e.getSource() == btnSetTime) {
Thread2();
}
}
});
}
public void Thread2() {
Thread t2 = new Thread() {
public void run() {
try {
for(;;) {
int hour = Integer.parseInt(tfhour.getText());
int minute = Integer.parseInt(tfminute.getText());
int second = Integer.parseInt(tfsecond.getText());
lblKlockan.setText(hour + ":" + minute + ":" + second);
sleep(1000);
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};t2.start();
}
public void Thread1() {
Thread t1 = new Thread() {
public void run() {
try {
for(;;) {
Calendar cal = Calendar.getInstance();
int hour = cal.get(Calendar.HOUR_OF_DAY);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
lblKlockan.setText(hour + ":" + minute + ":" + second);
sleep(1000);
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};t1.start();
}
}
So as I can see, the int hour = Integer.parseInt(tfhour.getText()); will probably not count as a Clock if I change to my own clock later on if i'm right? In that case, How can I fix it?
I hope I have all my problems out here in the post and I hope anyone here is willing to help me aswell :)
EDIT:
To make it easier to see:
EDIT PART 3:0
You have to define a global variable to stop the thread 1, when the thread 2 starts. Here is an example,
//define a variable that controls the thread 1
static boolean clockSet = false;
Now thread 1 is written such as it runs only when the clockSet is false, that is clock not set by a click.
Thread t1 = new Thread(){
public void run(){
while(!clockSet){
Calendar cal = Calendar.getInstance();
int hour = cal.get(Calendar.HOUR_OF_DAY);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
lblKlockan.setText(hour + ":" + minute + ":" + second);
try {
sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
};
In your thread 2, set the clockSet to true, so the thread 1 will stop. I see you are just displaying the value entered, but not setting those on a Calendar object. So create a Calendar object in thread 2, set the user defined values, and increment the time after every second of sleep.
Thread t2 = new Thread(){
public void run(){
clockSet = true;
Calendar cal = Calendar.getInstance();
cal.set(Calendar.HOUR_OF_DAY, Integer.parseInt(tfhour.getText()));
cal.set(Calendar.MINUTE, Integer.parseInt(tfminute.getText()));
cal.set(Calendar.SECOND, Integer.parseInt(tfsecond.getText()));
while(true){
int hour = cal.get(Calendar.HOUR_OF_DAY);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
lblKlockan.setText(hour + ":" + minute + ":" + second);
try {
sleep(1000);
cal.add(Calendar.SECOND, 1);
} catch (InterruptedException e) {
e.printStackTrace();}
}
}
};
Have fun..!
Sure, you see the code
try {
for(;;) {
int hour = Integer.parseInt(tfhour.getText());//this one
int minute = Integer.parseInt(tfminute.getText());//and this one
int second = Integer.parseInt(tfsecond.getText());//and this too
lblKlockan.setText(hour + ":" + minute + ":" + second);
sleep(1000);
}
you are setting hour, minute & second each and every time inside the for loop. So the clock is reseting.
Make them to get initialize only once, i.e. take them out of the loop.
Further this code
for(;;) {
Calendar cal = Calendar.getInstance();
int hour = cal.get(Calendar.HOUR_OF_DAY);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);
lblKlockan.setText(hour + ":" + minute + ":" + second);
sleep(1000);
}
is making your timer work as clock and not a timer because after 1 sec. the hour, minute & second are set to the values according to the time you get from Calendar.
Due to this your code will work as a clock that show the current time.
In my opinion you don't need the second thread at all. What I would do in this case is create three Int fields, hour-, minute- and second-offset, which you change when the button is pressed to, for example, hourOffset = Calendar.HOUR_OF_DAY - Integer.parseInt(tfhour.getText())%24; (example for the hours). Than you just need to add the offset to the time in thread1, which allways works since you start with 0 as offset.
I am wondering the best way to keep a timer going in the background while a game is played.
I am programming a version of the HiLo game (in Java), which gives a user a certain amount of time to determine a number. If a guess is not correct, the game will tell the user whether the name is too high or too low.
I'm keeping track of time using System.currentTimeMillis() and seeing how much time has elapsed. This seems to work well, and so far I have been checking to see how much time has elapsed each time a new number is entered. For example, currently the app output looks like this:
Welcome to HiLo!
You have 10 seconds to guess a number I'm thinking of between 1 and 100.
> 67
Too high.
> 29
Too low.
Half of your time is gone! Only 5 seconds remains!
> 37
Too high.
> 33
Oops! Time is up - try again.
As you can see, currently, it can only check when I enter a new number how much time is passed.
I have tried creating a thread to start with a timer, however, when I start it, it keeps counting until the time is exhausted, without going on to the thread.run(int guess) which will be run when there is a new guess. I want to be able to still make guesses while the counter runs. Here is my attempt at a new implementation for thread.start():
public void start(int time_sent) throws InterruptedException {
time = time_sent;
startTime = (System.currentTimeMillis() / 1000);
while (1==1) {
long elapsed = ((System.currentTimeMillis() / 1000) - (startTime));
if (elapsed >= (time)) {
System.out.println("Oops! Time is up - try again.");
System.exit(0);
}
else if (elapsed >= (time/2) && !halfWarning) {
System.out.println("Half of your time is gone! Only " + (time/2) + " seconds remains!");
halfWarning = true;
}
}
}
How can I continue running this counter in the background?
This is one more approach:
public void game() {
Scanner scanner = new Scanner(System.in);
int time = 10; // sec
message("You have " + time + " seconds to guess...");
new Thread(new Background(System.currentTimeMillis() / 1000, time)).start();
while (true) {
String s = scanner.next();
if (s.equals("55")) {
message("You win");
System.exit(0);
} else {
message("try again...");
}
}
}
private void message(String str) {
System.out.println(str);
System.out.print("> "); // monit
}
You start 1 thread with behavior implemented in Background class. Next you enter while loop to capture user inputs. The Background thread works in background...
private class Background implements Runnable {
private long startTime;
private long time;
private boolean halfWarning;
private Background(long startTime, long time) {
this.startTime = startTime;
this.time = time;
}
#Override
public void run() {
while (true) {
long now = System.currentTimeMillis() / 1000;
long elapsed = now - startTime;
if (elapsed >= (time / 2) && !halfWarning) {
message("\n Half of your time is gone! Only " + (time / 2) + " seconds remains!");
halfWarning = true;
}
if (elapsed >= time) {
message("\n Oops! Time is up - try again.");
System.exit(0);
}
try {
Thread.sleep(100);
} catch (InterruptedException e) {
//ignore
}
}
}
}
Use a ScheduledExecutorService to execute concurrent actions in the future:
ScheduledExecutorService ses = Executors.newSingleThreadScheduledExecutor();
ScheduledFuture<?> half = ses.schedule(new Runnable() {
#Override
public void run() {
System.out.println("Half of your time is gone!");
}
}, time / 2, TimeUnit.SECONDS);
ScheduledFuture<?> full = ses.schedule(new Runnable() {
#Override
public void run() {
System.out.println("Oops! Time is up - try again.");
// System.exit(0) ?
}
}, time, TimeUnit.SECONDS);
// check
if (input == toGuess) {
half.cancel();
full.cancel();
}
You could have a Timer thread that prints out these messages and shuts down the listening program.
It might inspire you :
public static class Game extends TimerTask {
private long start;
private long end;
public Game(long end) {
super();
this.start = System.currentTimeMillis();
this.end = end;
}
#Override
public void run() {
while (System.currentTimeMillis() - start < end)
System.out.println(System.currentTimeMillis());
}
}
public static void main(String[] args) {
TimerTask task = new Game(10000);
Timer timer = new Timer();
timer.schedule(task,0);
}