CountDownTimer Is Not Cancelling --- Continues to Run After Cancel() - android

I've implemented a CountDownTimer in my code as follows: At the top of the class, I create
CountDownTimer myTimer;
Then when a user presses button Start, the following method is called:
private void countme()
{
final int tick = 500;
final int countTime = 10000;
myTimer = new CountDownTimer(countTime, tick) {
#Override
public void onTick(final long millisUntilFinished) { }
#Override
public void onFinish() {
myPicture.setVisibility(View.GONE);
}
};
myTimer.start();
}
I have button Stop all myTimer.cancel(). As you can see, if the timer is not cancelled, myPicture will disappear.
Even if I click the stop button so that myTimer.cancel() is called (I checked this with log statements), the counter still continues to count down and to make the picture disappear when it's done.
Why isn't it stopping? How do I get it to actually cancel?
To clarify, I do know how to implement Runnable timers, but they are not as accurate for my needs as CountDownTimers are, which is why I'm not using them in this case.

After a lot of tries, trick is to declare the timer in onCreate but start and cancel it in some other method. The onFinish() will not call after cancelling the timer.
myTimer = new CountDownTimer(COUNT_DOWN_TIME, TICK) {
#Override
public void onTick(final long millisUntilFinished) {
((TextView) findViewById(R.id.textView3)).setText(""
+ millisUntilFinished);
}
#Override
public void onFinish() {
findViewById(R.id.timer_imageBiew).setVisibility(View.GONE);
}
};
private fun startTimer() {
myTimer .start()
}
private fun stopTimer() {
myTimer .cancel()
}

Here in your method countme() you are initializing myTimer, so outside this method myTimer has no value.
Use this
Declare at the top
CountDownTimer myTimer;
final int tick = 500;
final int countTime = 10000;
In the onCreate method of Activity or Fragment
myTimer = new CountDownTimer(countTime, tick) {
#Override
public void onTick(final long millisUntilFinished) { }
#Override
public void onFinish() {
myPicture.setVisibility(View.GONE);
}
};
Now use myTimer.start() to start and myTimer.cancel() to stop it.
Hope you understood.

Your post is very odd. I just tried doing a sample activity:
public class MainActivity extends AppCompatActivity {
CountDownTimer myTimer;
Button btnStart;
Button btnCancel;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.sample2);
btnStart = (Button) findViewById(R.id.start);
btnStart.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
countme();
Toast.makeText(MainActivity.this, "Count Started!", Toast.LENGTH_SHORT).show();
}
});
btnCancel = (Button) findViewById(R.id.cancel_timer);
btnCancel.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
myTimer.cancel();
Toast.makeText(MainActivity.this, "Clicked Stop Timer!", Toast.LENGTH_SHORT).show();
}
});
}
private void countme() {
final int tick = 500;
final int countTime = 10000;
myTimer = new CountDownTimer(countTime, tick) {
#Override
public void onTick(final long millisUntilFinished) {
Log.d(MainActivity.class.getSimpleName(), "onTick()");
}
#Override
public void onFinish() {
// myPicture.setVisibility(View.GONE);
Toast.makeText(MainActivity.this, "In onFinish()", Toast.LENGTH_SHORT).show();
}
};
myTimer.start();
}
}
It works perfectly fine. It stops the timer. But I went and looked around and found this answer where it mentions that CountDownTimer doesn't seem to work, so he suggested to use a Timer instead. Do check it out. Cheers!

This is working example , I have implemented both handler and timer you can pick one .
import android.app.Activity;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.os.Handler;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;
public class MainActivity extends Activity {
private CountDownTimer myTimer;
final int TICK = 500;
final int COUNT_DOWN_TIME = 2000;
// Option 2 using handler
private Handler myhandler = new Handler();
private Runnable runnable;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Option 1 using timer
myTimer = new CountDownTimer(COUNT_DOWN_TIME, TICK) {
#Override
public void onTick(final long millisUntilFinished) {
((TextView) findViewById(R.id.textView3)).setText(""
+ millisUntilFinished);
}
#Override
public void onFinish() {
findViewById(R.id.timer_imageBiew).setVisibility(View.GONE);
}
};
// Option 2 using handler
runnable = new Runnable() {
#Override
public void run() {
findViewById(R.id.handlerImageView).setVisibility(View.GONE);
}
};
findViewById(R.id.start_timer).setOnClickListener(
new OnClickListener() {
#Override
public void onClick(View v) {
// Option 1 using timer
myTimer.start();
// Option 2 using handler
myhandler.postDelayed(runnable, COUNT_DOWN_TIME);
}
});
findViewById(R.id.stop_timer).setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// Option 1 stop timer
myTimer.cancel();
// Option 2 stop handler
myhandler.removeCallbacks(runnable);
}
});
}
}

Related

Loop a Countdown timer X number of times,

I'm trying to loop my countdown timer for a specific number of times, but I'm not sure where I should add my for loop... Currently trying to do an interval timer function (I know there's a way to do it via Handler, but I'm still a beginner and got kind of confused on how I shoul use the handler)
I've tried adding it at '.start' and the StartTimer function but the countdown time still stays at 0. Would be great if any assistance is given as I'm still a beginner.. Thanks!
package com.example.bushykai.myapplication;
import android.os.CountDownTimer;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class Timer extends AppCompatActivity {
private static final long START_TIME_IN_MILLIS=10000;
private int sets = 3;
private TextView textViewCountdown;
private Button buttonStartPause;
private Button buttonReset;
private CountDownTimer countDownTimer;
private boolean timerRunning;
private long timeLeftInMillis = START_TIME_IN_MILLIS;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_timer);
textViewCountdown = findViewById(R.id.countdownTimer);
buttonStartPause = findViewById(R.id.startPause);
buttonReset= findViewById(R.id.reset);
buttonStartPause.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (timerRunning) {
pauseTimer();
}
else {
startTimer();
}
}
});
buttonReset.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
resetTimer();
}
});
updateCountDownText();
}
private void pauseTimer() {
countDownTimer.cancel();
timerRunning = false;
buttonStartPause.setText("Start");
buttonReset.setVisibility(View.VISIBLE);
}
private void startTimer() {
countDownTimer = new CountDownTimer(timeLeftInMillis, 1000) {
#Override
public void onTick(long millisUntilFinished) {
timeLeftInMillis = millisUntilFinished;
updateCountDownText();
}
#Override
public void onFinish() {
timerRunning = false;
buttonStartPause.setText("Start");
buttonStartPause.setVisibility(View.INVISIBLE);
buttonReset.setVisibility(View.VISIBLE);
}
}.start();
timerRunning = true;
buttonStartPause.setText("Pause");
buttonReset.setVisibility((View.INVISIBLE));
}
private void resetTimer() {
timeLeftInMillis = START_TIME_IN_MILLIS;
updateCountDownText();
buttonReset.setVisibility(View.INVISIBLE);
buttonStartPause.setVisibility(View.VISIBLE);
}
private void updateCountDownText() {
int minutes = (int) (timeLeftInMillis / 1000 ) / 60;
int seconds = (int) (timeLeftInMillis / 1000 ) % 60;
String timeLeftFormatted = String.format("%02d:%02d", minutes, seconds);
textViewCountdown.setText(timeLeftFormatted);
}
}
You have to add a Runnable Handler to your class try code below and modify with your Countdown Timer
public Handler timerHandler = new Handler();
public Runnable timerRunnable = new Runnable() {
#Override
public void run() {
//show alert or DO Whatever
}
};
public void timerStart() {
timerStop();
timerHandler.postDelayed(timerRunnable, Constants.TIMER_TIME_OUT);
}
public void timerStop() {
timerHandler.removeCallbacks(timerRunnable);
}

Reset value to default when using OnclickListener in Android

I'm trying to do some example about countdown timer using Button and set OnclickListener for that Button. My Default value is 10 and it will be decrease each second, how can i reset my value back to 10?
CountDownTimer cannot be restarted, it can only be used once. You either have to create your own count down class that can handle being restarted, or just create a new instance of your CountDownTimer and cancel the old instance.
See the example code below where we have a CountDownTimer that counts down for 10 seconds in 1 second intervals, a Button that resets the timer when clicked (by cancelling the current timer and starting a new one), and a TextView that displays the time left in the current timer.
public class YourActivity extends Activity {
private CountDownTimer countDownTimer;
private TextView timerDisplayTextView;
private static final long TEN_SECONDS = TimeUnit.SECONDS.toMillis(10);
private static final long COUNTDOWN_INTERVAL = TimeUnit.SECONDS.toMillis(1);
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
Button myButton; // initialized here
// timerDisplayTextView initialized here
myButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
countDownTimer.cancel();
countDownTimer = getNewCountDownTimer(TEN_SECONDS);
countDownTimer.start();
showTimeInTextView(TEN_SECONDS);
}
});
countDownTimer = getNewCountDownTimer(TEN_SECONDS);
countDownTimer.start();
}
#Override
protected void onDestroy() {
super.onDestroy();
countDownTimer.cancel();
}
private void showTimeInTextView(long millisecondsLeft) {
timerDisplayTextView.setText(TimeUnit.MILLISECONDS.toSeconds(millisecondsLeft) + " seconds left");
}
private CountDownTimer getNewCountDownTimer(long length) {
return new CountDownTimer(length, COUNTDOWN_INTERVAL) {
#Override
public void onTick(long millisUntilFinished) {
showTimeInTextView(millisUntilFinished);
}
#Override
public void onFinish() {
}
};
}
}

Restarting a CountDownTimer in a Dialog window after an OnTouchEvent in a fragment

I have a CountDownTimer that dismisses a dialog popup window. I would like for this timer to restart if the user touches the screen. Here is what I have so far,
public class dataCapture extends Fragment implements OnClickListener {
...
MotionEvent event;
View.OnTouchListener touchListener;
#Override
public void onCreate(Bundle savedDataEntryInstanceState) {
super.onCreate(savedDataEntryInstanceState);
setRetainInstance(true);
}
...
#Override
public View onCreateView
#Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btnHelpFilexml:
openHelpDialog();
break;
...
}
private void openHelpDialog() {
Button btnCloseWindow;
final Dialog helpDialog;
TextView tvHelpDialogTitle, tvHelpDialogBody;
helpDialog = new Dialog(getActivity(), android.R.style.Theme_Translucent);
helpDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
helpDialog.setCancelable(true);
helpDialog.setContentView(R.layout.help_dialog);
tvHelpDialogTitle = (TextView) helpDialog.findViewById(R.id.tvHelpDialogTitle);
tvHelpDialogTitle.setText("DataCapture Help");
tvHelpDialogBody = (TextView) helpDialog.findViewById(R.id.tvHelpDialogBody);
tvHelpDialogBody.setText("Start of help text\n" +
"This is help text\n" +
"\n" +
"Here we go...\n" +
...
"This is the end.");
btnCloseWindow = (Button) helpDialog.findViewById(R.id.btnCloseWindow);
btnCloseWindow.setText("Close");
btnCloseWindow.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
helpDialog.dismiss();
}
});
CountDownTimer countDownTimer = new CountDownTimer(30000, 1000) {
// new countDownTimer(30000, 1000) {//makes popup go away after 30 secs
#Override
public void onTick(long millisUntilFinished) {//Do something every second...
}
#Override
public void onFinish() {//action at end of specified time
helpDialog.dismiss();
}
}.start();
#Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction()==MotionEvent.ACTION_DOWN) {
countDownTimer.cancel();
countDownTimer.start();
}
return super.onTouchEvent(event);
}
helpDialog.show();
}
}
Any suggestions regarding how best to implement this function would be highly appreciated. Copious TIA.
UPDATE Got it. Solution below. Thanks.
public class dataCapture extends Fragment implements OnClickListener {
...
private static final int COUNTDOWN_TIME_MS = 30000;
Handler handlerHelpDialogTimer;
Runnable runnableHelpDialogDismissCountdown;
Dialog helpDialog;
private Dialog getHelpDialog() {
Button btnCloseWindow;
final Dialog helpDialog;
TextView tvHelpDialogTitle, tvHelpDialogBody;
helpDialog = new Dialog(getActivity(), android.R.style.Theme_Translucent);
helpDialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
helpDialog.setCancelable(true);
helpDialog.setContentView(R.layout.help_dialog);
tvHelpDialogTitle = (TextView) helpDialog.findViewById(R.id.tvHelpDialogTitle);
tvHelpDialogTitle.setText("DataCapture Help");
tvHelpDialogBody.setText("Start of help text\n" +
"This is help text\n" +
"\n" +
"Wheee, here we go\n" +
...
"this is the end.");
btnCloseWindow = (Button) helpDialog.findViewById(R.id.btnCloseWindow);
btnCloseWindow.setText("Close");
btnCloseWindow.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
helpDialog.dismiss();
}
});
tvHelpDialogBody.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View tvHelpDialogBody, MotionEvent event) {
cancelCountdown();
startCountdown();
return false;
}
});
helpDialog.show();
return (helpDialog);
}
private void showHelpDialog() {
helpDialog = getHelpDialog();
helpDialog.show();
startCountdown();
}
synchronized private void startCountdown() {
handlerHelpDialogTimer.postDelayed(getCountdownTask(), COUNTDOWN_TIME_MS);
}
synchronized private void cancelCountdown() {
handlerHelpDialogTimer.removeCallbacks(runnableHelpDialogDismissCountdown);
runnableHelpDialogDismissCountdown = null;
}
private Runnable getCountdownTask() {
Runnable task = new Runnable() {
#Override
public void run() {
if (helpDialog != null) helpDialog.dismiss();
}
};
runnableHelpDialogDismissCountdown = task;
return task;
}
Ditch the countdown timer. Instead use a handler, for example:
public class AwesomeActivity extends Activity {
private static final int COUNTDOWN_TIME_MS = 300000;
Handler handler;
Runnable countDown;
Dialog helpDialog;
#Override public void onCreate(Bundle b) {
super.onCreate(b);
handler = new Handler();
}
/* call cancelCountdown() in onPause* */
private Dialog getHelpDialog() { return /* fill in the details */ }
private void showHelpDialog() {
helpDialog = getHelpDialog();
helpDialog.show();
startCountDown();
}
synchronized private void startCountDown() {
handler.postDelayed(getCountdownTask(), COUNTDOWN_TIME_MS);
}
synchronized private void cancelCountdown() {
handler.removeCallbacks(countdown);
countdown = null;
}
private Runnable getCountdownTask() {
Runnable task = new Runnable() {
#Override public void run() {
if (helpDialog != null) helpDialog.dismiss();
}
};
countDown = task;
return task;
}
}
Now in onTouch(MotionEvent e) you can cancel and start the countdown.
I'll leave it to you to figure out how to handle onPause and onResume :)
Furthermore, if you really wanted to, you could override a Dialog and put the Handler timer countdown logic inside that class, overriding show() to start the countdown and then add a method such as, restartTimer() you can call after a TOUCH_DOWN. If you do, you can then also override onSaveInstanceState and onRestoreInstanceState in the Dialog subclass, to cancel the callback, stash the time remaining, then pull out the time remaining and re-postdelay the countdown runnable with the remaining time.

Timertask change TextView setText()? [duplicate]

Can someone give a simple example of updating a textfield every second or so?
I want to make a flying ball and need to calculate/update the ball coordinates every second, that's why I need some sort of a timer.
I don't get anything from here.
ok since this isn't cleared up yet there are 3 simple ways to handle this.
Below is an example showing all 3 and at the bottom is an example showing just the method I believe is preferable. Also remember to clean up your tasks in onPause, saving state if necessary.
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.Handler.Callback;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class main extends Activity {
TextView text, text2, text3;
long starttime = 0;
//this posts a message to the main thread from our timertask
//and updates the textfield
final Handler h = new Handler(new Callback() {
#Override
public boolean handleMessage(Message msg) {
long millis = System.currentTimeMillis() - starttime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
text.setText(String.format("%d:%02d", minutes, seconds));
return false;
}
});
//runs without timer be reposting self
Handler h2 = new Handler();
Runnable run = new Runnable() {
#Override
public void run() {
long millis = System.currentTimeMillis() - starttime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
text3.setText(String.format("%d:%02d", minutes, seconds));
h2.postDelayed(this, 500);
}
};
//tells handler to send a message
class firstTask extends TimerTask {
#Override
public void run() {
h.sendEmptyMessage(0);
}
};
//tells activity to run on ui thread
class secondTask extends TimerTask {
#Override
public void run() {
main.this.runOnUiThread(new Runnable() {
#Override
public void run() {
long millis = System.currentTimeMillis() - starttime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
text2.setText(String.format("%d:%02d", minutes, seconds));
}
});
}
};
Timer timer = new Timer();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
text = (TextView)findViewById(R.id.text);
text2 = (TextView)findViewById(R.id.text2);
text3 = (TextView)findViewById(R.id.text3);
Button b = (Button)findViewById(R.id.button);
b.setText("start");
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Button b = (Button)v;
if(b.getText().equals("stop")){
timer.cancel();
timer.purge();
h2.removeCallbacks(run);
b.setText("start");
}else{
starttime = System.currentTimeMillis();
timer = new Timer();
timer.schedule(new firstTask(), 0,500);
timer.schedule(new secondTask(), 0,500);
h2.postDelayed(run, 0);
b.setText("stop");
}
}
});
}
#Override
public void onPause() {
super.onPause();
timer.cancel();
timer.purge();
h2.removeCallbacks(run);
Button b = (Button)findViewById(R.id.button);
b.setText("start");
}
}
the main thing to remember is that the UI can only be modified from the main ui thread so use a handler or activity.runOnUIThread(Runnable r);
Here is what I consider to be the preferred method.
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class TestActivity extends Activity {
TextView timerTextView;
long startTime = 0;
//runs without a timer by reposting this handler at the end of the runnable
Handler timerHandler = new Handler();
Runnable timerRunnable = new Runnable() {
#Override
public void run() {
long millis = System.currentTimeMillis() - startTime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
timerTextView.setText(String.format("%d:%02d", minutes, seconds));
timerHandler.postDelayed(this, 500);
}
};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test_activity);
timerTextView = (TextView) findViewById(R.id.timerTextView);
Button b = (Button) findViewById(R.id.button);
b.setText("start");
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Button b = (Button) v;
if (b.getText().equals("stop")) {
timerHandler.removeCallbacks(timerRunnable);
b.setText("start");
} else {
startTime = System.currentTimeMillis();
timerHandler.postDelayed(timerRunnable, 0);
b.setText("stop");
}
}
});
}
#Override
public void onPause() {
super.onPause();
timerHandler.removeCallbacks(timerRunnable);
Button b = (Button)findViewById(R.id.button);
b.setText("start");
}
}
It is simple!
You create new timer.
Timer timer = new Timer();
Then you extend the timer task
class UpdateBallTask extends TimerTask {
Ball myBall;
public void run() {
//calculate the new position of myBall
}
}
And then add the new task to the Timer with some update interval
final int FPS = 40;
TimerTask updateBall = new UpdateBallTask();
timer.scheduleAtFixedRate(updateBall, 0, 1000/FPS);
Disclaimer: This is not the ideal solution. This is solution using the Timer class (as asked by OP). In Android SDK, it is recommended to use the Handler class (there is example in the accepted answer).
If you also need to run your code on UI thread (and not on timer thread), take a look on the blog: http://steve.odyfamily.com/?p=12
public class myActivity extends Activity {
private Timer myTimer;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
myTimer = new Timer();
myTimer.schedule(new TimerTask() {
#Override
public void run() {
TimerMethod();
}
}, 0, 1000);
}
private void TimerMethod()
{
//This method is called directly by the timer
//and runs in the same thread as the timer.
//We call the method that will work with the UI
//through the runOnUiThread method.
this.runOnUiThread(Timer_Tick);
}
private Runnable Timer_Tick = new Runnable() {
public void run() {
//This method runs in the same thread as the UI.
//Do something to the UI thread here
}
};
}
If one just want to schedule a countdown until a time in the future with regular notifications on intervals along the way, you can use the CountDownTimer class that is available since API level 1.
new CountDownTimer(30000, 1000) {
public void onTick(long millisUntilFinished) {
editText.setText("Seconds remaining: " + millisUntilFinished / 1000);
}
public void onFinish() {
editText.setText("Done");
}
}.start();
This is some simple code for a timer:
Timer timer = new Timer();
TimerTask t = new TimerTask() {
#Override
public void run() {
System.out.println("1");
}
};
timer.scheduleAtFixedRate(t,1000,1000);
I think you can do it in Rx way like:
timerSubscribe = Observable.interval(1, TimeUnit.SECONDS)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<Long>() {
#Override
public void call(Long aLong) {
//TODO do your stuff
}
});
And cancel this like:
timerSubscribe.unsubscribe();
Rx Timer http://reactivex.io/documentation/operators/timer.html
I'm surprised that there is no answer that would mention solution with RxJava2. It is really simple and provides an easy way to setup timer in Android.
First you need to setup Gradle dependency, if you didn't do so already:
implementation "io.reactivex.rxjava2:rxjava:2.x.y"
(replace x and y with current version number)
Since we have just a simple, NON-REPEATING TASK, we can use Completable object:
Completable.timer(2, TimeUnit.SECONDS, Schedulers.computation())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(() -> {
// Timer finished, do something...
});
For REPEATING TASK, you can use Observable in a similar way:
Observable.interval(2, TimeUnit.SECONDS, Schedulers.computation())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(tick -> {
// called every 2 seconds, do something...
}, throwable -> {
// handle error
});
Schedulers.computation() ensures that our timer is running on background thread and .observeOn(AndroidSchedulers.mainThread()) means code we run after timer finishes will be done on main thread.
To avoid unwanted memory leaks, you should ensure to unsubscribe when Activity/Fragment is destroyed.
Because this question is still attracting a lot of users from google search(about Android timer) I would like to insert my two coins.
First of all, the Timer class will be deprecated in Java 9 (read the accepted answer).
The official suggested way is to use ScheduledThreadPoolExecutor which is more effective and features-rich that can additionally schedule commands to run after a given delay, or to execute periodically. Plus,it gives additional flexibility and capabilities of ThreadPoolExecutor.
Here is an example of using plain functionalities.
Create executor service:
final ScheduledExecutorService SCHEDULER = Executors.newScheduledThreadPool(1);
Just schedule you runnable:
final Future<?> future = SCHEDULER.schedule(Runnable task, long delay,TimeUnit unit);
You can now use future to cancel the task or check if it is done for example:
future.isDone();
Hope you will find this useful for creating a tasks in Android.
Complete example:
ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
Future<?> sampleFutureTimer = scheduler.schedule(new Runnable(), 120, TimeUnit.SECONDS);
if (sampleFutureTimer.isDone()){
// Do something which will save world.
}
for whom wants to do this in kotlin:
val timer = fixedRateTimer(period = 1000L) {
val currentTime: Date = Calendar.getInstance().time
runOnUiThread {
tvFOO.text = currentTime.toString()
}
}
for stopping the timer you can use this:
timer.cancel()
this function has many other options, give it a try
import kotlin.concurrent.fixedRateTimer
val timer = fixedRateTimer("Tag", false, 1000, 2500) { /* Your code here */ }
Pretty simple with Kotlin
You want your UI updates to happen in the already-existent UI thread.
The best way is to use a Handler that uses postDelayed to run a Runnable after a delay (each run schedules the next); clear the callback with removeCallbacks.
You're already looking in the right place, so look at it again, perhaps clarify why that code sample isn't what you want. (See also the identical article at Updating the UI from a Timer).
He're is simplier solution, works fine in my app.
public class MyActivity extends Acitivity {
TextView myTextView;
boolean someCondition=true;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_activity);
myTextView = (TextView) findViewById(R.id.refreshing_field);
//starting our task which update textview every 1000 ms
new RefreshTask().execute();
}
//class which updates our textview every second
class RefreshTask extends AsyncTask {
#Override
protected void onProgressUpdate(Object... values) {
super.onProgressUpdate(values);
String text = String.valueOf(System.currentTimeMillis());
myTextView.setText(text);
}
#Override
protected Object doInBackground(Object... params) {
while(someCondition) {
try {
//sleep for 1s in background...
Thread.sleep(1000);
//and update textview in ui thread
publishProgress();
} catch (InterruptedException e) {
e.printStackTrace();
};
return null;
}
}
}
You can also use an animator for it:
int secondsToRun = 999;
ValueAnimator timer = ValueAnimator.ofInt(secondsToRun);
timer.setDuration(secondsToRun * 1000).setInterpolator(new LinearInterpolator());
timer.addUpdateListener(new ValueAnimator.AnimatorUpdateListener()
{
#Override
public void onAnimationUpdate(ValueAnimator animation)
{
int elapsedSeconds = (int) animation.getAnimatedValue();
int minutes = elapsedSeconds / 60;
int seconds = elapsedSeconds % 60;
textView.setText(String.format("%d:%02d", minutes, seconds));
}
});
timer.start();
For those who can't rely on Chronometer, I made a utility class out of one of the suggestions:
public class TimerTextHelper implements Runnable {
private final Handler handler = new Handler();
private final TextView textView;
private volatile long startTime;
private volatile long elapsedTime;
public TimerTextHelper(TextView textView) {
this.textView = textView;
}
#Override
public void run() {
long millis = System.currentTimeMillis() - startTime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
textView.setText(String.format("%d:%02d", minutes, seconds));
if (elapsedTime == -1) {
handler.postDelayed(this, 500);
}
}
public void start() {
this.startTime = System.currentTimeMillis();
this.elapsedTime = -1;
handler.post(this);
}
public void stop() {
this.elapsedTime = System.currentTimeMillis() - startTime;
handler.removeCallbacks(this);
}
public long getElapsedTime() {
return elapsedTime;
}
}
to use..just do:
TimerTextHelper timerTextHelper = new TimerTextHelper(textView);
timerTextHelper.start();
.....
timerTextHelper.stop();
long elapsedTime = timerTextHelper.getElapsedTime();
enter code here
Thread th=new Thread(new Runnable() {
#Override
public void run() {
try { for(int i=0;i<5;i++) {
b1.setText(""+i);
Thread.sleep(5000);
runOnUiThread(new Runnable() {
#Override
public void run() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
pp();
}
}
});
}} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
th.start();
Here is the solution for this you need to add the following class in your code. And you can directly add a view to your XML file.
import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build;
import android.util.AttributeSet;
import android.view.View;
import android.widget.TextView;
import java.util.Locale;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.TimeUnit;
public class TimerTextView extends TextView {
private static final int DEFAULT_INTERVAL = 1000;
private Timer timer = new Timer();
private long endTime = 0;
private long interval = DEFAULT_INTERVAL;
private boolean isCanceled = false;
public TimerTextView(Context context) {
super(context);
}
public TimerTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public TimerTextView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#TargetApi(Build.VERSION_CODES.LOLLIPOP)
public TimerTextView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
}
#Override protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
stopTimer();
}
#Override protected void onVisibilityChanged(View changedView, int visibility) {
super.onVisibilityChanged(changedView, visibility);
if (VISIBLE == visibility) {
startTimer();
} else {
stopTimer();
}
}
public void setInterval(long interval) {
if (interval >= 0) {
this.interval = interval;
stopTimer();
startTimer();
}
}
public void setEndTime(long endTime) {
if (endTime >= 0) {
this.endTime = endTime;
stopTimer();
startTimer();
}
}
private void startTimer() {
if (endTime == 0) {
return;
}
if (isCanceled) {
timer = new Timer();
isCanceled = false;
}
timer.scheduleAtFixedRate(new TimerTask() {
#Override public void run() {
if (null == getHandler()) {
return;
}
getHandler().post(new Runnable() {
#Override public void run() {
setText(getDurationBreakdown(endTime - System.currentTimeMillis()));
}
});
}
}, 0, interval);
}
private void stopTimer() {
timer.cancel();
isCanceled = true;
}
private String getDurationBreakdown(long diff) {
long millis = diff;
if (millis < 0) {
return "00:00:00";
}
long hours = TimeUnit.MILLISECONDS.toHours(millis);
millis -= TimeUnit.HOURS.toMillis(hours);
long minutes = TimeUnit.MILLISECONDS.toMinutes(millis);
millis -= TimeUnit.MINUTES.toMillis(minutes);
long seconds = TimeUnit.MILLISECONDS.toSeconds(millis);
return String.format(Locale.ENGLISH, "%02d:%02d:%02d", hours, minutes, seconds);
//return "${getWithLeadZero(hours)}:${getWithLeadZero(minutes)}:${getWithLeadZero(seconds)}"
}
}
You need to create a thread to handle the update loop and use it to update the textarea. The tricky part though is that only the main thread can actually modify the ui so the update loop thread needs to signal the main thread to do the update. This is done using a Handler.
Check out this link: http://developer.android.com/guide/topics/ui/dialogs.html#
Click on the section titled "Example ProgressDialog with a second thread". It's an example of exactly what you need to do, except with a progress dialog instead of a textfield.
void method(boolean u,int max)
{
uu=u;
maxi=max;
if (uu==true)
{
CountDownTimer uy = new CountDownTimer(maxi, 1000)
{
public void onFinish()
{
text.setText("Finish");
}
#Override
public void onTick(long l) {
String currentTimeString=DateFormat.getTimeInstance().format(new Date());
text.setText(currentTimeString);
}
}.start();
}
else{text.setText("Stop ");
}
If anyone is interested, I started playing around with creating a standard object to run on an activities UI thread. Seems to work ok. Comments welcome. I'd love this to be available on the layout designer as a component to drag onto an Activity. Can't believe something like that doesn't already exist.
package com.example.util.timer;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
public class ActivityTimer {
private Activity m_Activity;
private boolean m_Enabled;
private Timer m_Timer;
private long m_Delay;
private long m_Period;
private ActivityTimerListener m_Listener;
private ActivityTimer _self;
private boolean m_FireOnce;
public ActivityTimer() {
m_Delay = 0;
m_Period = 100;
m_Listener = null;
m_FireOnce = false;
_self = this;
}
public boolean isEnabled() {
return m_Enabled;
}
public void setEnabled(boolean enabled) {
if (m_Enabled == enabled)
return;
// Disable any existing timer before we enable a new one
Disable();
if (enabled) {
Enable();
}
}
private void Enable() {
if (m_Enabled)
return;
m_Enabled = true;
m_Timer = new Timer();
if (m_FireOnce) {
m_Timer.schedule(new TimerTask() {
#Override
public void run() {
OnTick();
}
}, m_Delay);
} else {
m_Timer.schedule(new TimerTask() {
#Override
public void run() {
OnTick();
}
}, m_Delay, m_Period);
}
}
private void Disable() {
if (!m_Enabled)
return;
m_Enabled = false;
if (m_Timer == null)
return;
m_Timer.cancel();
m_Timer.purge();
m_Timer = null;
}
private void OnTick() {
if (m_Activity != null && m_Listener != null) {
m_Activity.runOnUiThread(new Runnable() {
#Override
public void run() {
m_Listener.OnTimerTick(m_Activity, _self);
}
});
}
if (m_FireOnce)
Disable();
}
public long getDelay() {
return m_Delay;
}
public void setDelay(long delay) {
m_Delay = delay;
}
public long getPeriod() {
return m_Period;
}
public void setPeriod(long period) {
if (m_Period == period)
return;
m_Period = period;
}
public Activity getActivity() {
return m_Activity;
}
public void setActivity(Activity activity) {
if (m_Activity == activity)
return;
m_Activity = activity;
}
public ActivityTimerListener getActionListener() {
return m_Listener;
}
public void setActionListener(ActivityTimerListener listener) {
m_Listener = listener;
}
public void start() {
if (m_Enabled)
return;
Enable();
}
public boolean isFireOnlyOnce() {
return m_FireOnce;
}
public void setFireOnlyOnce(boolean fireOnce) {
m_FireOnce = fireOnce;
}
}
In the activity, I have this onStart:
#Override
protected void onStart() {
super.onStart();
m_Timer = new ActivityTimer();
m_Timer.setFireOnlyOnce(true);
m_Timer.setActivity(this);
m_Timer.setActionListener(this);
m_Timer.setDelay(3000);
m_Timer.start();
}
Here is a simple reliable way...
Put the following code in your Activity, and the tick() method will be called every second in the UI thread while your activity is in the "resumed" state. Of course, you can change the tick() method to do what you want, or to be called more or less frequently.
#Override
public void onPause() {
_handler = null;
super.onPause();
}
private Handler _handler;
#Override
public void onResume() {
super.onResume();
_handler = new Handler();
Runnable r = new Runnable() {
public void run() {
if (_handler == _h0) {
tick();
_handler.postDelayed(this, 1000);
}
}
private final Handler _h0 = _handler;
};
r.run();
}
private void tick() {
System.out.println("Tick " + System.currentTimeMillis());
}
For those interested, the "_h0=_handler" code is necessary to avoid two timers running simultaneously if your activity is paused and resumed within the tick period.
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Timer;
import java.util.TimerTask;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.TextView;
import android.app.Activity;
public class MainActivity extends Activity {
CheckBox optSingleShot;
Button btnStart, btnCancel;
TextView textCounter;
Timer timer;
MyTimerTask myTimerTask;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
optSingleShot = (CheckBox)findViewById(R.id.singleshot);
btnStart = (Button)findViewById(R.id.start);
btnCancel = (Button)findViewById(R.id.cancel);
textCounter = (TextView)findViewById(R.id.counter);
btnStart.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View arg0) {
if(timer != null){
timer.cancel();
}
//re-schedule timer here
//otherwise, IllegalStateException of
//"TimerTask is scheduled already"
//will be thrown
timer = new Timer();
myTimerTask = new MyTimerTask();
if(optSingleShot.isChecked()){
//singleshot delay 1000 ms
timer.schedule(myTimerTask, 1000);
}else{
//delay 1000ms, repeat in 5000ms
timer.schedule(myTimerTask, 1000, 5000);
}
}});
btnCancel.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
if (timer!=null){
timer.cancel();
timer = null;
}
}
});
}
class MyTimerTask extends TimerTask {
#Override
public void run() {
Calendar calendar = Calendar.getInstance();
SimpleDateFormat simpleDateFormat =
new SimpleDateFormat("dd:MMMM:yyyy HH:mm:ss a");
final String strDate = simpleDateFormat.format(calendar.getTime());
runOnUiThread(new Runnable(){
#Override
public void run() {
textCounter.setText(strDate);
}});
}
}
}
.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context=".MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:autoLink="web"
android:text="http://android-er.blogspot.com/"
android:textStyle="bold" />
<CheckBox
android:id="#+id/singleshot"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Single Shot"/>
If you have delta time already.
public class Timer {
private float lastFrameChanged;
private float frameDuration;
private Runnable r;
public Timer(float frameDuration, Runnable r) {
this.frameDuration = frameDuration;
this.lastFrameChanged = 0;
this.r = r;
}
public void update(float dt) {
lastFrameChanged += dt;
if (lastFrameChanged > frameDuration) {
lastFrameChanged = 0;
r.run();
}
}
}
I Abstract Timer away and made it a separate class:
Timer.java
import android.os.Handler;
public class Timer {
IAction action;
Handler timerHandler = new Handler();
int delayMS = 1000;
public Timer(IAction action, int delayMS) {
this.action = action;
this.delayMS = delayMS;
}
public Timer(IAction action) {
this(action, 1000);
}
public Timer() {
this(null);
}
Runnable timerRunnable = new Runnable() {
#Override
public void run() {
if (action != null)
action.Task();
timerHandler.postDelayed(this, delayMS);
}
};
public void start() {
timerHandler.postDelayed(timerRunnable, 0);
}
public void stop() {
timerHandler.removeCallbacks(timerRunnable);
}
}
And Extract main action from Timer class out as
IAction.java
public interface IAction {
void Task();
}
And I used it just like this:
MainActivity.java
public class MainActivity extends Activity implements IAction{
...
Timer timerClass;
#Override
protected void onCreate(Bundle savedInstanceState) {
...
timerClass = new Timer(this,1000);
timerClass.start();
...
}
...
int i = 1;
#Override
public void Task() {
runOnUiThread(new Runnable() {
#Override
public void run() {
timer.setText(i + "");
i++;
}
});
}
...
}
I Hope This Helps 😊👌
I use this way:
String[] array={
"man","for","think"
}; int j;
then below the onCreate
TextView t = findViewById(R.id.textView);
new CountDownTimer(5000,1000) {
#Override
public void onTick(long millisUntilFinished) {}
#Override
public void onFinish() {
t.setText("I "+array[j] +" You");
j++;
if(j== array.length-1) j=0;
start();
}
}.start();
it's easy way to solve this problem.

How to set timer in android?

Can someone give a simple example of updating a textfield every second or so?
I want to make a flying ball and need to calculate/update the ball coordinates every second, that's why I need some sort of a timer.
I don't get anything from here.
ok since this isn't cleared up yet there are 3 simple ways to handle this.
Below is an example showing all 3 and at the bottom is an example showing just the method I believe is preferable. Also remember to clean up your tasks in onPause, saving state if necessary.
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.Handler.Callback;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class main extends Activity {
TextView text, text2, text3;
long starttime = 0;
//this posts a message to the main thread from our timertask
//and updates the textfield
final Handler h = new Handler(new Callback() {
#Override
public boolean handleMessage(Message msg) {
long millis = System.currentTimeMillis() - starttime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
text.setText(String.format("%d:%02d", minutes, seconds));
return false;
}
});
//runs without timer be reposting self
Handler h2 = new Handler();
Runnable run = new Runnable() {
#Override
public void run() {
long millis = System.currentTimeMillis() - starttime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
text3.setText(String.format("%d:%02d", minutes, seconds));
h2.postDelayed(this, 500);
}
};
//tells handler to send a message
class firstTask extends TimerTask {
#Override
public void run() {
h.sendEmptyMessage(0);
}
};
//tells activity to run on ui thread
class secondTask extends TimerTask {
#Override
public void run() {
main.this.runOnUiThread(new Runnable() {
#Override
public void run() {
long millis = System.currentTimeMillis() - starttime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
text2.setText(String.format("%d:%02d", minutes, seconds));
}
});
}
};
Timer timer = new Timer();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
text = (TextView)findViewById(R.id.text);
text2 = (TextView)findViewById(R.id.text2);
text3 = (TextView)findViewById(R.id.text3);
Button b = (Button)findViewById(R.id.button);
b.setText("start");
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Button b = (Button)v;
if(b.getText().equals("stop")){
timer.cancel();
timer.purge();
h2.removeCallbacks(run);
b.setText("start");
}else{
starttime = System.currentTimeMillis();
timer = new Timer();
timer.schedule(new firstTask(), 0,500);
timer.schedule(new secondTask(), 0,500);
h2.postDelayed(run, 0);
b.setText("stop");
}
}
});
}
#Override
public void onPause() {
super.onPause();
timer.cancel();
timer.purge();
h2.removeCallbacks(run);
Button b = (Button)findViewById(R.id.button);
b.setText("start");
}
}
the main thing to remember is that the UI can only be modified from the main ui thread so use a handler or activity.runOnUIThread(Runnable r);
Here is what I consider to be the preferred method.
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class TestActivity extends Activity {
TextView timerTextView;
long startTime = 0;
//runs without a timer by reposting this handler at the end of the runnable
Handler timerHandler = new Handler();
Runnable timerRunnable = new Runnable() {
#Override
public void run() {
long millis = System.currentTimeMillis() - startTime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
timerTextView.setText(String.format("%d:%02d", minutes, seconds));
timerHandler.postDelayed(this, 500);
}
};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test_activity);
timerTextView = (TextView) findViewById(R.id.timerTextView);
Button b = (Button) findViewById(R.id.button);
b.setText("start");
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Button b = (Button) v;
if (b.getText().equals("stop")) {
timerHandler.removeCallbacks(timerRunnable);
b.setText("start");
} else {
startTime = System.currentTimeMillis();
timerHandler.postDelayed(timerRunnable, 0);
b.setText("stop");
}
}
});
}
#Override
public void onPause() {
super.onPause();
timerHandler.removeCallbacks(timerRunnable);
Button b = (Button)findViewById(R.id.button);
b.setText("start");
}
}
It is simple!
You create new timer.
Timer timer = new Timer();
Then you extend the timer task
class UpdateBallTask extends TimerTask {
Ball myBall;
public void run() {
//calculate the new position of myBall
}
}
And then add the new task to the Timer with some update interval
final int FPS = 40;
TimerTask updateBall = new UpdateBallTask();
timer.scheduleAtFixedRate(updateBall, 0, 1000/FPS);
Disclaimer: This is not the ideal solution. This is solution using the Timer class (as asked by OP). In Android SDK, it is recommended to use the Handler class (there is example in the accepted answer).
If you also need to run your code on UI thread (and not on timer thread), take a look on the blog: http://steve.odyfamily.com/?p=12
public class myActivity extends Activity {
private Timer myTimer;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
myTimer = new Timer();
myTimer.schedule(new TimerTask() {
#Override
public void run() {
TimerMethod();
}
}, 0, 1000);
}
private void TimerMethod()
{
//This method is called directly by the timer
//and runs in the same thread as the timer.
//We call the method that will work with the UI
//through the runOnUiThread method.
this.runOnUiThread(Timer_Tick);
}
private Runnable Timer_Tick = new Runnable() {
public void run() {
//This method runs in the same thread as the UI.
//Do something to the UI thread here
}
};
}
If one just want to schedule a countdown until a time in the future with regular notifications on intervals along the way, you can use the CountDownTimer class that is available since API level 1.
new CountDownTimer(30000, 1000) {
public void onTick(long millisUntilFinished) {
editText.setText("Seconds remaining: " + millisUntilFinished / 1000);
}
public void onFinish() {
editText.setText("Done");
}
}.start();
This is some simple code for a timer:
Timer timer = new Timer();
TimerTask t = new TimerTask() {
#Override
public void run() {
System.out.println("1");
}
};
timer.scheduleAtFixedRate(t,1000,1000);
I think you can do it in Rx way like:
timerSubscribe = Observable.interval(1, TimeUnit.SECONDS)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<Long>() {
#Override
public void call(Long aLong) {
//TODO do your stuff
}
});
And cancel this like:
timerSubscribe.unsubscribe();
Rx Timer http://reactivex.io/documentation/operators/timer.html
I'm surprised that there is no answer that would mention solution with RxJava2. It is really simple and provides an easy way to setup timer in Android.
First you need to setup Gradle dependency, if you didn't do so already:
implementation "io.reactivex.rxjava2:rxjava:2.x.y"
(replace x and y with current version number)
Since we have just a simple, NON-REPEATING TASK, we can use Completable object:
Completable.timer(2, TimeUnit.SECONDS, Schedulers.computation())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(() -> {
// Timer finished, do something...
});
For REPEATING TASK, you can use Observable in a similar way:
Observable.interval(2, TimeUnit.SECONDS, Schedulers.computation())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(tick -> {
// called every 2 seconds, do something...
}, throwable -> {
// handle error
});
Schedulers.computation() ensures that our timer is running on background thread and .observeOn(AndroidSchedulers.mainThread()) means code we run after timer finishes will be done on main thread.
To avoid unwanted memory leaks, you should ensure to unsubscribe when Activity/Fragment is destroyed.
Because this question is still attracting a lot of users from google search(about Android timer) I would like to insert my two coins.
First of all, the Timer class will be deprecated in Java 9 (read the accepted answer).
The official suggested way is to use ScheduledThreadPoolExecutor which is more effective and features-rich that can additionally schedule commands to run after a given delay, or to execute periodically. Plus,it gives additional flexibility and capabilities of ThreadPoolExecutor.
Here is an example of using plain functionalities.
Create executor service:
final ScheduledExecutorService SCHEDULER = Executors.newScheduledThreadPool(1);
Just schedule you runnable:
final Future<?> future = SCHEDULER.schedule(Runnable task, long delay,TimeUnit unit);
You can now use future to cancel the task or check if it is done for example:
future.isDone();
Hope you will find this useful for creating a tasks in Android.
Complete example:
ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
Future<?> sampleFutureTimer = scheduler.schedule(new Runnable(), 120, TimeUnit.SECONDS);
if (sampleFutureTimer.isDone()){
// Do something which will save world.
}
for whom wants to do this in kotlin:
val timer = fixedRateTimer(period = 1000L) {
val currentTime: Date = Calendar.getInstance().time
runOnUiThread {
tvFOO.text = currentTime.toString()
}
}
for stopping the timer you can use this:
timer.cancel()
this function has many other options, give it a try
import kotlin.concurrent.fixedRateTimer
val timer = fixedRateTimer("Tag", false, 1000, 2500) { /* Your code here */ }
Pretty simple with Kotlin
You want your UI updates to happen in the already-existent UI thread.
The best way is to use a Handler that uses postDelayed to run a Runnable after a delay (each run schedules the next); clear the callback with removeCallbacks.
You're already looking in the right place, so look at it again, perhaps clarify why that code sample isn't what you want. (See also the identical article at Updating the UI from a Timer).
He're is simplier solution, works fine in my app.
public class MyActivity extends Acitivity {
TextView myTextView;
boolean someCondition=true;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_activity);
myTextView = (TextView) findViewById(R.id.refreshing_field);
//starting our task which update textview every 1000 ms
new RefreshTask().execute();
}
//class which updates our textview every second
class RefreshTask extends AsyncTask {
#Override
protected void onProgressUpdate(Object... values) {
super.onProgressUpdate(values);
String text = String.valueOf(System.currentTimeMillis());
myTextView.setText(text);
}
#Override
protected Object doInBackground(Object... params) {
while(someCondition) {
try {
//sleep for 1s in background...
Thread.sleep(1000);
//and update textview in ui thread
publishProgress();
} catch (InterruptedException e) {
e.printStackTrace();
};
return null;
}
}
}
You can also use an animator for it:
int secondsToRun = 999;
ValueAnimator timer = ValueAnimator.ofInt(secondsToRun);
timer.setDuration(secondsToRun * 1000).setInterpolator(new LinearInterpolator());
timer.addUpdateListener(new ValueAnimator.AnimatorUpdateListener()
{
#Override
public void onAnimationUpdate(ValueAnimator animation)
{
int elapsedSeconds = (int) animation.getAnimatedValue();
int minutes = elapsedSeconds / 60;
int seconds = elapsedSeconds % 60;
textView.setText(String.format("%d:%02d", minutes, seconds));
}
});
timer.start();
For those who can't rely on Chronometer, I made a utility class out of one of the suggestions:
public class TimerTextHelper implements Runnable {
private final Handler handler = new Handler();
private final TextView textView;
private volatile long startTime;
private volatile long elapsedTime;
public TimerTextHelper(TextView textView) {
this.textView = textView;
}
#Override
public void run() {
long millis = System.currentTimeMillis() - startTime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
textView.setText(String.format("%d:%02d", minutes, seconds));
if (elapsedTime == -1) {
handler.postDelayed(this, 500);
}
}
public void start() {
this.startTime = System.currentTimeMillis();
this.elapsedTime = -1;
handler.post(this);
}
public void stop() {
this.elapsedTime = System.currentTimeMillis() - startTime;
handler.removeCallbacks(this);
}
public long getElapsedTime() {
return elapsedTime;
}
}
to use..just do:
TimerTextHelper timerTextHelper = new TimerTextHelper(textView);
timerTextHelper.start();
.....
timerTextHelper.stop();
long elapsedTime = timerTextHelper.getElapsedTime();
enter code here
Thread th=new Thread(new Runnable() {
#Override
public void run() {
try { for(int i=0;i<5;i++) {
b1.setText(""+i);
Thread.sleep(5000);
runOnUiThread(new Runnable() {
#Override
public void run() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
pp();
}
}
});
}} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
th.start();
Here is the solution for this you need to add the following class in your code. And you can directly add a view to your XML file.
import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build;
import android.util.AttributeSet;
import android.view.View;
import android.widget.TextView;
import java.util.Locale;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.TimeUnit;
public class TimerTextView extends TextView {
private static final int DEFAULT_INTERVAL = 1000;
private Timer timer = new Timer();
private long endTime = 0;
private long interval = DEFAULT_INTERVAL;
private boolean isCanceled = false;
public TimerTextView(Context context) {
super(context);
}
public TimerTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public TimerTextView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#TargetApi(Build.VERSION_CODES.LOLLIPOP)
public TimerTextView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
}
#Override protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
stopTimer();
}
#Override protected void onVisibilityChanged(View changedView, int visibility) {
super.onVisibilityChanged(changedView, visibility);
if (VISIBLE == visibility) {
startTimer();
} else {
stopTimer();
}
}
public void setInterval(long interval) {
if (interval >= 0) {
this.interval = interval;
stopTimer();
startTimer();
}
}
public void setEndTime(long endTime) {
if (endTime >= 0) {
this.endTime = endTime;
stopTimer();
startTimer();
}
}
private void startTimer() {
if (endTime == 0) {
return;
}
if (isCanceled) {
timer = new Timer();
isCanceled = false;
}
timer.scheduleAtFixedRate(new TimerTask() {
#Override public void run() {
if (null == getHandler()) {
return;
}
getHandler().post(new Runnable() {
#Override public void run() {
setText(getDurationBreakdown(endTime - System.currentTimeMillis()));
}
});
}
}, 0, interval);
}
private void stopTimer() {
timer.cancel();
isCanceled = true;
}
private String getDurationBreakdown(long diff) {
long millis = diff;
if (millis < 0) {
return "00:00:00";
}
long hours = TimeUnit.MILLISECONDS.toHours(millis);
millis -= TimeUnit.HOURS.toMillis(hours);
long minutes = TimeUnit.MILLISECONDS.toMinutes(millis);
millis -= TimeUnit.MINUTES.toMillis(minutes);
long seconds = TimeUnit.MILLISECONDS.toSeconds(millis);
return String.format(Locale.ENGLISH, "%02d:%02d:%02d", hours, minutes, seconds);
//return "${getWithLeadZero(hours)}:${getWithLeadZero(minutes)}:${getWithLeadZero(seconds)}"
}
}
You need to create a thread to handle the update loop and use it to update the textarea. The tricky part though is that only the main thread can actually modify the ui so the update loop thread needs to signal the main thread to do the update. This is done using a Handler.
Check out this link: http://developer.android.com/guide/topics/ui/dialogs.html#
Click on the section titled "Example ProgressDialog with a second thread". It's an example of exactly what you need to do, except with a progress dialog instead of a textfield.
void method(boolean u,int max)
{
uu=u;
maxi=max;
if (uu==true)
{
CountDownTimer uy = new CountDownTimer(maxi, 1000)
{
public void onFinish()
{
text.setText("Finish");
}
#Override
public void onTick(long l) {
String currentTimeString=DateFormat.getTimeInstance().format(new Date());
text.setText(currentTimeString);
}
}.start();
}
else{text.setText("Stop ");
}
If anyone is interested, I started playing around with creating a standard object to run on an activities UI thread. Seems to work ok. Comments welcome. I'd love this to be available on the layout designer as a component to drag onto an Activity. Can't believe something like that doesn't already exist.
package com.example.util.timer;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
public class ActivityTimer {
private Activity m_Activity;
private boolean m_Enabled;
private Timer m_Timer;
private long m_Delay;
private long m_Period;
private ActivityTimerListener m_Listener;
private ActivityTimer _self;
private boolean m_FireOnce;
public ActivityTimer() {
m_Delay = 0;
m_Period = 100;
m_Listener = null;
m_FireOnce = false;
_self = this;
}
public boolean isEnabled() {
return m_Enabled;
}
public void setEnabled(boolean enabled) {
if (m_Enabled == enabled)
return;
// Disable any existing timer before we enable a new one
Disable();
if (enabled) {
Enable();
}
}
private void Enable() {
if (m_Enabled)
return;
m_Enabled = true;
m_Timer = new Timer();
if (m_FireOnce) {
m_Timer.schedule(new TimerTask() {
#Override
public void run() {
OnTick();
}
}, m_Delay);
} else {
m_Timer.schedule(new TimerTask() {
#Override
public void run() {
OnTick();
}
}, m_Delay, m_Period);
}
}
private void Disable() {
if (!m_Enabled)
return;
m_Enabled = false;
if (m_Timer == null)
return;
m_Timer.cancel();
m_Timer.purge();
m_Timer = null;
}
private void OnTick() {
if (m_Activity != null && m_Listener != null) {
m_Activity.runOnUiThread(new Runnable() {
#Override
public void run() {
m_Listener.OnTimerTick(m_Activity, _self);
}
});
}
if (m_FireOnce)
Disable();
}
public long getDelay() {
return m_Delay;
}
public void setDelay(long delay) {
m_Delay = delay;
}
public long getPeriod() {
return m_Period;
}
public void setPeriod(long period) {
if (m_Period == period)
return;
m_Period = period;
}
public Activity getActivity() {
return m_Activity;
}
public void setActivity(Activity activity) {
if (m_Activity == activity)
return;
m_Activity = activity;
}
public ActivityTimerListener getActionListener() {
return m_Listener;
}
public void setActionListener(ActivityTimerListener listener) {
m_Listener = listener;
}
public void start() {
if (m_Enabled)
return;
Enable();
}
public boolean isFireOnlyOnce() {
return m_FireOnce;
}
public void setFireOnlyOnce(boolean fireOnce) {
m_FireOnce = fireOnce;
}
}
In the activity, I have this onStart:
#Override
protected void onStart() {
super.onStart();
m_Timer = new ActivityTimer();
m_Timer.setFireOnlyOnce(true);
m_Timer.setActivity(this);
m_Timer.setActionListener(this);
m_Timer.setDelay(3000);
m_Timer.start();
}
Here is a simple reliable way...
Put the following code in your Activity, and the tick() method will be called every second in the UI thread while your activity is in the "resumed" state. Of course, you can change the tick() method to do what you want, or to be called more or less frequently.
#Override
public void onPause() {
_handler = null;
super.onPause();
}
private Handler _handler;
#Override
public void onResume() {
super.onResume();
_handler = new Handler();
Runnable r = new Runnable() {
public void run() {
if (_handler == _h0) {
tick();
_handler.postDelayed(this, 1000);
}
}
private final Handler _h0 = _handler;
};
r.run();
}
private void tick() {
System.out.println("Tick " + System.currentTimeMillis());
}
For those interested, the "_h0=_handler" code is necessary to avoid two timers running simultaneously if your activity is paused and resumed within the tick period.
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Timer;
import java.util.TimerTask;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.TextView;
import android.app.Activity;
public class MainActivity extends Activity {
CheckBox optSingleShot;
Button btnStart, btnCancel;
TextView textCounter;
Timer timer;
MyTimerTask myTimerTask;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
optSingleShot = (CheckBox)findViewById(R.id.singleshot);
btnStart = (Button)findViewById(R.id.start);
btnCancel = (Button)findViewById(R.id.cancel);
textCounter = (TextView)findViewById(R.id.counter);
btnStart.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View arg0) {
if(timer != null){
timer.cancel();
}
//re-schedule timer here
//otherwise, IllegalStateException of
//"TimerTask is scheduled already"
//will be thrown
timer = new Timer();
myTimerTask = new MyTimerTask();
if(optSingleShot.isChecked()){
//singleshot delay 1000 ms
timer.schedule(myTimerTask, 1000);
}else{
//delay 1000ms, repeat in 5000ms
timer.schedule(myTimerTask, 1000, 5000);
}
}});
btnCancel.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
if (timer!=null){
timer.cancel();
timer = null;
}
}
});
}
class MyTimerTask extends TimerTask {
#Override
public void run() {
Calendar calendar = Calendar.getInstance();
SimpleDateFormat simpleDateFormat =
new SimpleDateFormat("dd:MMMM:yyyy HH:mm:ss a");
final String strDate = simpleDateFormat.format(calendar.getTime());
runOnUiThread(new Runnable(){
#Override
public void run() {
textCounter.setText(strDate);
}});
}
}
}
.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context=".MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:autoLink="web"
android:text="http://android-er.blogspot.com/"
android:textStyle="bold" />
<CheckBox
android:id="#+id/singleshot"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Single Shot"/>
If you have delta time already.
public class Timer {
private float lastFrameChanged;
private float frameDuration;
private Runnable r;
public Timer(float frameDuration, Runnable r) {
this.frameDuration = frameDuration;
this.lastFrameChanged = 0;
this.r = r;
}
public void update(float dt) {
lastFrameChanged += dt;
if (lastFrameChanged > frameDuration) {
lastFrameChanged = 0;
r.run();
}
}
}
I Abstract Timer away and made it a separate class:
Timer.java
import android.os.Handler;
public class Timer {
IAction action;
Handler timerHandler = new Handler();
int delayMS = 1000;
public Timer(IAction action, int delayMS) {
this.action = action;
this.delayMS = delayMS;
}
public Timer(IAction action) {
this(action, 1000);
}
public Timer() {
this(null);
}
Runnable timerRunnable = new Runnable() {
#Override
public void run() {
if (action != null)
action.Task();
timerHandler.postDelayed(this, delayMS);
}
};
public void start() {
timerHandler.postDelayed(timerRunnable, 0);
}
public void stop() {
timerHandler.removeCallbacks(timerRunnable);
}
}
And Extract main action from Timer class out as
IAction.java
public interface IAction {
void Task();
}
And I used it just like this:
MainActivity.java
public class MainActivity extends Activity implements IAction{
...
Timer timerClass;
#Override
protected void onCreate(Bundle savedInstanceState) {
...
timerClass = new Timer(this,1000);
timerClass.start();
...
}
...
int i = 1;
#Override
public void Task() {
runOnUiThread(new Runnable() {
#Override
public void run() {
timer.setText(i + "");
i++;
}
});
}
...
}
I Hope This Helps 😊👌
I use this way:
String[] array={
"man","for","think"
}; int j;
then below the onCreate
TextView t = findViewById(R.id.textView);
new CountDownTimer(5000,1000) {
#Override
public void onTick(long millisUntilFinished) {}
#Override
public void onFinish() {
t.setText("I "+array[j] +" You");
j++;
if(j== array.length-1) j=0;
start();
}
}.start();
it's easy way to solve this problem.

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