I want to repeat a for loop inside below code inside a service every some time ,but it print only one line and runs one time only
public void startTimer() {
timer = new Timer();
initializeTimerTask();
timer.schedule(timerTask, 10000);
}
public void initializeTimerTask() {
timerTask = new TimerTask() {
public void run() {
for (int i=0; i<10; i++){
Log.i("TAG", " inside method ");}
}
};
}
You are calling the following method.
public void schedule(TimerTask task, long delay)
So the task executes only once after delay.
If you want to execute it periodically you need to call the bellow method.(you may pass same value for delay and period)
public void schedule(TimerTask task, long delay, long period)
Your another query is it prints first line only. Most probably this is an issue with the Log. try System.out.print() instead of Log.i() to debug.
class MyTimerTask extends TimerTask {
private int counter = 1;
public void run() {
timerHandler.post(new Runnable() {
public void run() {
Toast.makeText(this, "" + counter, Toast.LENGTH_SHORT).show();
counter++;
}
});
if (counter == 10) {
myTimer.cancel();
myTimer.purge();
}
}
}
//Thats the usage like on ButtonClick
MyTimerTask myTimerTask = new MyTimerTask();
Timer myTimer = new Timer();
myTimer.schedule(myTimerTask, 500, 1000);
Do you really need to run Loop ?
I have an application in Java where I need to schedule a TimerTaskwhich will be executed after 500ms , however if a certain event occurs, I must reset the timer for this task (so that we must wait another 500ms for it to execute). I have a timer declared for the whole class. I use the following code:
public static void main(String[] args) {
if (curr_pck == my_pck) {
timer.cancel();
timer.purge();
timer = new Timer();
timer.schedule(new TimerTask() {
#Override
public void run() {
myTask();
}
}, 500);
}
}
public static void myTask() {
timer.cancel();
timer.purge();
timer = new Timer();
timer.schedule(new TimerTask() {
#Override
public void run() {
myTask();
}
}, 500);
//EXECUTE CODE WHICH ISN'T RELEVANT TO THE QUESTION
}
I know that if I use timer.cancel() I can't reuse the timer object, however I thought reinitialising it in the line timer = new Timer() should solve this issue. Is there any way around this?
EXCEPTION on line timer.schedule(new TimerTask() { inside myTask() function:
java.lang.IllegalStateException: Timer already cancelled.
Create a class Timerr with the appropriate methods. Then access it as if it were a normal timer.
public class Timerr
{
private Timer timer;
public Timerr()
{
timer = new Timer();
start();
}
public void start()
{
timer.schedule(new TimerTask()
{
#Override
public void run()
{
System.out.println("hi");
}
}, 500);
}
public void reset()
{
timer.cancel();
timer.purge();
start();
}
}
Create instance
private Timerr timer = new Timerr();
Do your reset
if(condition)
{
timerr.reset();
}
You may want to check out Java's Swing timer. It works somewhat differently and you may have to write an internal class or an actionlistener, but the Swing timer includes .stop() and .restart(), which seem like they would work better in your application.
Im trying to make CountDownTimer start few times in a loop but it only starts one time and it should start at least 2 more times,
I've tried for loop and just While(x !=2)
case R.id.tbWait:
if (waiting.isChecked()){
int x = 0;
do {
turnOnLights();
new CountDownTimer(2000, 1000){
#Override
public void onTick(long millisUntilFinished) {
}
#Override
public void onFinish(){
turnOffLights();
}
}.start();
x++;
} while (x !=2);
}
break;
I have tried this aswell but it makes the application not responsive and have to force close it :(
case R.id.tbWait:
while (waiting.isChecked()){ //Using While instead of if statemnt
turnOnLights();
new CountDownTimer(2000, 1000){
#Override
public void onTick(long millisUntilFinished) {
}
#Override
public void onFinish(){
turnOffLights();
}
}.start();
}
break;
Question is how do i loop this when i Toggle the Toggle Button tbWait on?
turnOnLights() then wait 2 seconds then turnOffLights() like the waiting button in the car ? sorry for my bad english and im really new to this ^^
im using AndroidStudio
Do it the android way, use a Handler!
Make a Handler, a Runnable to turn the lights on, and a Runnable to turn them off:
public class YourClass extends ProbablySomeClass{
Handler lightsHandler; //The android.os.Handler one, not the java one
Runnable lightsON = new Runnable(){
#Override
public void run(){
if(waiting.isChecked){
turnLightsOn();
lightsHandler.postDelayed(lightsOff, 2000);
}
else lightsHandler.postDelayed(lightsON, 1000);
}
}
Runnable lightsOff = new Runnable(){
#Override
public void run(){
turnLightsOff();
lightsHandler.postDelayed(lightsON, 2000);
}
}
public YourClass(SomeType someParameter){
init(someParameters); //Whatever your constructor does
lightsHandler = new Handler();
lightsHandler.post(lightsOn)
}
Now all your button has to do is un/check that variable, and it will automatically flash every 2 seconds while it is checked.
I am writing simple game, where some action must accelerating during the process. The question is how to change timer's period?
timer = new Timer();
timerTask = new TimerTask() {
#Override
public void run() {
runOnUiThread(new Runnable() {
#Override
public void run() {
//
// I need to change timer's period here
//
}
});
}
};
timer.schedule(timerTask, 0, period);
Will be glad to hear any advices.
I assume that you are performing some logic within the run() method of the TimerTask.
I think a simpler way to go about this would be to use a Handler. This is possibly more idiomatic for Android:
private final Handler mHandler = new Handler();
private final Runnable mTask = new Runnable() {
#Override
public void run() {
// Do your logic.
// Now post again.
mHandler.postDelayed(mTask, /* choose a new delay period */);
}
};
public void init() {
delay = 1000L; // 1 second.
mHandler.postDelayed(mTask, delay);
}
I have one simple question regarding Java TimerTask. How do I pause/resume two TimerTask tasks based on a certain condition? For example I have two timers that run between each other. When a certain condition has been met inside the task of first timer, the first timer stops and starts the second timer, and the same thing happens when a certain condition has been met inside the task of second timer. The class below shows exactly what I mean:
public class TimerTest {
Timer timer1;
Timer timer2;
volatile boolean a = false;
public TimerTest() {
timer1 = new Timer();
timer2 = new Timer();
}
public void runStart() {
timer1.scheduleAtFixedRate(new Task1(), 0, 1000);
}
class Task1 extends TimerTask {
public void run() {
System.out.println("Checking a");
a = SomeClass.getSomeStaticValue();
if (a) {
// Pause/stop timer1, start/resume timer2 for 5 seconds
timer2.schedule(new Task2(), 5000);
}
}
}
class Task2 extends TimerTask{
public void run() {
System.out.println("Checking a");
a = SomeClass.getSomeStaticValue();
if (!a) {
// Pause/stop timer2, back to timer1
timer1.scheduleAtFixedRate(new Task1(), 0, 1000);
}
// Do something...
}
}
public static void main(String args[]) {
TimerTest tt = new TimerTest();
tt.runStart();
}
}
So my question is, how do I pause timer1 while running timer2 and vice versa while timer2 is running? Performance and timing is my main concern as this needs to be implemented inside another running thread. By the way I am trying to implement these concurrent timers on Android.
Thanks for your help!
From TimerTask.cancel():
Note that calling this method from
within the run method of a repeating
timer task absolutely guarantees that
the timer task will not run again.
So once cancelled, it won't ever run again. You'd be better off instead using the more modern ScheduledExecutorService (from Java 5+).
Edit: The basic construct is:
ScheduledExecutorService exec = Executors.newSingleThreadScheduledExecutor();
exec.scheduleAtFixedRate(runnable, 0, 1000, TimeUnit.MILLISECONDS);
but looking into it there's no way of cancelling that task once its started without shutting down the service, which is a bit odd.
TimerTask might be easier in this case but you'll need to create a new instance when you start one up. It can't be reused.
Alternatively you could encapsulate each task as a separate transient service:
final ScheduledExecutorService exec = Executors.newSingleThreadScheduledExecutor();
Runnable task1 = new Runnable() {
public void run() {
a++;
if (a == 3) {
exec.shutdown();
exec = Executors.newSingleThreadScheduledExecutor();
exec.scheduleAtFixedRate(task2, 0, 1000, TimeUnit.MILLISECONDS)
}
}
};
exec.scheduleAtFixedRate(task1, 0, 1000, TimeUnit.MILLISECONDS);
easiest solution i found: just add a boolean in the run code in the timer task, like so:
timer.schedule( new TimerTask() {
public void run() {
if(!paused){
//do your thing
}
}
}, 0, 1000 );
If you have already canceled one timer, you can't re-start it, you'll have to create a new one.
See this answer, it contains a video and the source code how I did something similar.
Basically there are two method: pause and resume
In pause:
public void pause() {
this.timer.cancel();
}
In resume:
public void resume() {
this.timer = new Timer();
this.timer.schedule( aTask, 0, 1000 );
}
That makes the perception of pause/resume.
If your timers perform different actions based on the state of the application you may consider use the StatePattern
Fist define a abstract state:
abstract class TaskState {
public void run();
public TaskState next();
}
And provide as many states as you like. The key is that one state leads you to another.
class InitialState extends TaskState {
public void run() {
System.out.println( "starting...");
}
public TaskState next() {
return new FinalState();
}
}
class FinalState extends TaskState {
public void run() {
System.out.println("Finishing...");
}
public TaskState next(){
return new InitialState();
}
}
And then you change the state in your timer.
Timer timer = new Timer();
TaskState state = new InitialState();
timer.schedule( new TimerTask() {
public void run() {
this.state.run();
if( shouldChangeState() ) {
this.state = this.state.next();
}
}
}, 0, 1000 );
Finally, if what you need is to perform the same thing, but at different rates, you may consider using the TimingFramework. It is a bit more complex but let's you do cool animations, by allowing the painting of certain component take place at different rates ( instead of being linear )
In my opinion, this is somewhat misguided. If your code needs time guarantees, you can't use Timer anyway, nor would you want to. "This class does not offer real-time guarantees: it schedules tasks using the Object.wait(long) method."
The answer, IMHO, is that you don't want to pause and restart your timers. You just want to suppress their run methods from doing their business. And that's easy: you just wrap them in an if statement. The switch is on, they run, the switch is off, they miss that cycle.
Edit: The question has shifted substantially from what it was originally, but I'll leave this answer in case it helps anyone. My point is: if you don't care when your event fires in the N millisecond span (just that it doesn't EXCEED once every N milliseconds), you can just use conditionals on the run methods. This is, in fact, a very common case, especially when N is less than 1 second.
Reviewing your source code, here are the changes ( which pretty much validate my previous answer )
In task1:
// Stop timer1 and start timer2
timer1.cancel();
timer2 = new Timer(); // <-- just insert this line
timer2.scheduleAtFixedRate(new Task2(), 0, 1000);
and in task2:
// Stop timer2 and start timer1
timer2.cancel();
timer1 = new Timer(); // <-- just insert this other
timer1.scheduleAtFixedRate(new Task1(), 0, 1000);
It runs on my machine:
Android won't reuse a TimerTask that has already been scheduled once. So it's necessary to reinstantiate both the Timer and TimerTask, for example like this in a Fragment:
private Timer timer;
private TimerTask timerTask;
public void onResume ()
{
super.onResume();
timer = new Timer();
timerTask = new MyTimerTask();
timer.schedule(timerTask, 0, 1000);
}
public void onPause ()
{
super.onPause();
timer.cancel(); // Renders Timer unusable for further schedule() calls.
}
I am able to stop a timer and a task using following code:
if(null != timer)
{
timer.cancel();
Log.i(LOG_TAG,"Number of cancelled tasks purged: " + timer.purge());
timer = null;
}
if(task != null)
{
Log.i(LOG_TAG,"Tracking cancellation status: " + task.cancel());
task = null;
}
Timer timer1;
private boolean videoCompleteCDR=false;
private boolean isVideoPlaying=false;
int videoTime=0;
private int DEFAULT_VIDEO_PLAY_TIME = 30;
#Override
public View onCreate(){
isVideoPlaying = true; //when server response is successfully
}
#Override
public void onPause() {
super.onPause();
if(isVideoPlaying ) {
if(this.timer1 !=null) {
this.timer1.cancel();
}
}
}
#Override
public void onResume() {
super.onResume();
if(isVideoPlaying && !videoCompleteCDR) {
callTimerTask();
}
}
#Override
public void onHiddenChanged(boolean hidden) {
super.onHiddenChanged(hidden);
if (!hidden) {
printLog( "GameFragment visible ");
if(isVideoPlaying && !videoCompleteCDR) {
callTimerTask();
}
} else {
printLog("GameFragment in visible ");
if(isVideoPlaying) {
if(this.timer1 !=null) {
this.timer1.cancel();
}
}
}
}
private void callTimerTask() {
// TODO Timer for auto sliding
printLog( "callTimerTask Start" );
timer1 = new Timer();
timer1.schedule(new TimerTask() {
#Override
public void run() {
if (getActivity() != null) {
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
if (getActivity() == null) {
return;
}
videoTime++;
if(DEFAULT_VIDEO_PLAY_TIME ==videoTime){
videoCompleteCDR=true;
Log.e("KeshavTimer", "callTimerTask videoCompleteCDR called.... " +videoTime);
destroyTimer();
}
Log.e("KeshavTimer", "callTimerTask videoTime " +videoTime);
}
});
} else {
printLog("callTimerTask getActivity is null ");
}
}
}, 1000, 1000);
// TODO 300, 2000;
}
private void destroyTimer(){
this.timer1.cancel();
}