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I Want to create a timer which will run for 10 seconds. If the user have entered the correct answer the timer should restart. For that I have added cancel.countdowntimer(). But it's not working. The app crashes. Where should I use that countdowntimer.cancel() function? Should I use a method for countdowntimer.cancel()?
package com.example.vignesh.work;
import android.os.CountDownTimer;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.Random;
public class MainActivity extends AppCompatActivity {
Button b1;
int loc;
int total=0;
int mark=0;
Runnable run;
Handler handler;
CountDownTimer countDownTimer;
TextView textView4,textView2,textView1,textView3;
Button b11,b22,b33,b44;
Random random = new Random();
ArrayList<Integer> answers = new ArrayList<Integer>();
public void nextQuestion() {
new CountDownTimer(10000 + 100, 1000) {
#Override
public void onTick(long millisUntilFinished) {
textView3.setText(Long.toString(millisUntilFinished / 1000));
}
#Override
public void onFinish() {
textView3.setText("10");
}
}.start();
int a = random.nextInt(20) + 1;
int b = random.nextInt(20) + 1;
textView1.setText(Integer.toString(a) + "+" + Integer.toString(b));
loc = random.nextInt(4);
answers.clear();
for (int i = 0; i < 4; i++) {
if (i == loc) {
answers.add(a + b);
} else {
answers.add((a + b) + random.nextInt(10) + 1);
}
}
b11.setText(Integer.toString(answers.get(0)));
b22.setText(Integer.toString(answers.get(1)));
b33.setText(Integer.toString(answers.get(2)));
b44.setText(Integer.toString(answers.get(3)));
}
public void choose(View view)
{
if(view.getTag().toString().equals(Integer.toString(loc+1)))
{
textView4.setText("Correct");
mark++;
}
else
{
textView4.setText("Wrong");
}
total++;
try {
countDownTimer.cancel();
}
catch (Exception e)
{
Log.i("error",e.getMessage());
}
nextQuestion();
textView2.setText(Integer.toString(mark)+"/"+Integer.toString(total));
}
public void click(View view)
{
b1.setVisibility(view.INVISIBLE);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b1 = (Button)findViewById(R.id.buttongo);
b11 = (Button)findViewById(R.id.optiona);
b22 = (Button)findViewById(R.id.optionb);
b33 = (Button)findViewById(R.id.option3);
b44 = (Button)findViewById(R.id.option4);
textView1=(TextView)findViewById(R.id.textView1);
textView2=(TextView)findViewById(R.id.textView2);
textView3=(TextView)findViewById(R.id.textView3);
textView4=(TextView)findViewById(R.id.textView4);
nextQuestion();
}
}
**AFTER ADDING EXCEPTIONAL HANDLING THE ERROR WAS:Attempt to invoke virtual method 'void android.os.CountDownTimer.cancel()' on a null object reference**
Thanks.
You instantiate your CountDownTimer in nextQuestion() method, however you do not assign it in the countDownTimer variable defined in the top of your class: CountDownTimer countDownTimer;
Change the code inside nextQuestion() method to:
countDownTimer = new CountDownTimer(10000 + 100, 1000) {
#Override
public void onTick(long millisUntilFinished) {
textView3.setText(Long.toString(millisUntilFinished / 1000));
}
#Override
public void onFinish() {
textView3.setText("10");
}
};
countDownTimer.start();
Note that I am assigning the new CountDownTimer to countDownTimer variable and then start the timer by calling countDownTimer.start();.
Then check if countDownTimer is null before calling it to cancel:
if(countDownTimer != null) {
countDownTimer.cancel();
}
You are not initialising countDownTimer variable update your method like below and also check null before calling countDownTimer.cancel();
public void nextQuestion() {
countDownTimer = new CountDownTimer(10000 + 100, 1000) {
#Override
public void onTick(long millisUntilFinished) {
textView3.setText(Long.toString(millisUntilFinished / 1000));
}
#Override
public void onFinish() {
textView3.setText("10");
}
}.start();
int a = random.nextInt(20) + 1;
int b = random.nextInt(20) + 1;
textView1.setText(Integer.toString(a) + "+" + Integer.toString(b));
loc = random.nextInt(4);
answers.clear();
for (int i = 0; i < 4; i++) {
if (i == loc) {
answers.add(a + b);
} else {
answers.add((a + b) + random.nextInt(10) + 1);
}
}
b11.setText(Integer.toString(answers.get(0)));
b22.setText(Integer.toString(answers.get(1)));
b33.setText(Integer.toString(answers.get(2)));
b44.setText(Integer.toString(answers.get(3)));
}
I have a count down timer and if the user does not click this button on an even number I need to perform a certain method which will end my game. So basically if the user stops tapping I need the gameOver() method called.
import android.app.Activity;
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;
import android.widget.Toast;
public class GameScreen extends Activity {
private TextView time;
private Button start;
private Button cancel;
private Button gameButton;
private CountDownTimer countDownTimer;
public static int count = 0;
int foo = Integer.parseInt(time.getText().toString());
private View.OnClickListener btnClickListener = new View.OnClickListener(){
#Override
public void onClick(View v) {
switch(v.getId()){
case R.id.start_ID :
start();
break;
case R.id.cancel :
cancel();
break;
case R.id.gameButton_ID :
gameButton();
break;
}
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_game_screen);
start = (Button) findViewById(R.id.start_ID);
start.setOnClickListener(btnClickListener);
cancel = (Button) findViewById(R.id.cancel);
cancel.setOnClickListener(btnClickListener);
time = (TextView) findViewById(R.id.time);
gameButton = (Button) findViewById(R.id.gameButton_ID);
gameButton.setOnClickListener(btnClickListener);
}
public void start(){
time.setText("15");
countDownTimer = new CountDownTimer(15 * 1000, 1000) {
#Override
public void onTick(long millsUntilFinished){
time.setText("" + millsUntilFinished / 1000);
//this doesnt work and makes app crash when you hit start button
if((gameButton.isPressed() != true) && foo % 2 == 0){
gameOver();
}
}
public void onFinish(){
time.setText("Done !");
}
};
countDownTimer.start();
}
private void cancel(){
if(countDownTimer != null){
countDownTimer.cancel();
countDownTimer = null;
}
}
private void gameOver(){
Toast.makeText(getApplicationContext(), "You scored " + count, Toast.LENGTH_SHORT).show();
count = 0;
cancel();
}
private void gameButton(){
if(foo % 2 == 0 ) {
Toast.makeText(getApplicationContext(), "PASS", Toast.LENGTH_SHORT).show();
++count;
}
else{
gameOver();
}
}
}
What you can do is take one boolean called isClickedOnEvenNumber. Now when you press the button when even-number set isClickedOnEvenNumber as
isClickedOnEvenNumber = true;
Now check on every tick check that
if(isClickedOnEvenNumber)
//continue game
else
//end game
EDIT :
You can use a TimerTask that periodically verifies wether or not the Button was clicked. You do not need the counterBTnnotclicked variable any more.
So you can do something like this : (Am trying to write this quickly, so be aware of that)
class BtnClickIntegerHolder{
public int counterBtnClicked = 0;
}
class BtnClicksCheckerIntegerHolder{
public int btnClicks = 0;
}
final BtnClickIntegerHolder btnClickCounter = new BtnClickIntegerHolder();
yourButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
btnClickCounter.counterBtnClicked = btnClickCounter.counterBtnClicked + 1;
}
});
int period = 10000; // repeat every 10 secs.
final BtnClicksCheckerIntegerHolder btnClicksHolder = new BtnClicksCheckerIntegerHolder();
btnClicksHolder.btnClicks = btnClickCounter.counterBtnClicked;
Timer timer = new Timer();
timer.scheduleAtFixedRate(new TimerTask() {
public void run() {
if(btnClickCounter.counterBtnClicked == btnClicksHolder.btnClicks ){
//Button was not clicked
}
else{
//Button was clicked
}
btnClicksHolder.btnClicks = btnClickCounter.counterBtnClicked;
}
}, period, period);
So I designed an Android application about a year ago now in Android Studio to take care of some things at my college. However, I never "completely finished" it. The one thing that it is missing for me is when I click a button it starts a timer and outputs a string. However, if I press another button before that timer is up, it will say both at the same time. In looking online, I haven't found exactly what I was looking for so I thought I would open it up to the Stackoverflow community and maybe you can guide me in the right direction. Now for the code.
package com.example.james.texttospeech;
import android.os.Bundle;
import android.app.Activity;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.view.View;
import android.widget.EditText;
import android.speech.tts.TextToSpeech;
import android.speech.tts.TextToSpeech.OnInitListener;
import android.content.Intent;
import java.util.Locale;
import android.widget.Toast;
import android.os.CountDownTimer;
public class MainActivity extends Activity implements OnClickListener, OnInitListener {
//TTS object
private TextToSpeech myTTS;
//status check code
private int MY_DATA_CHECK_CODE = 0;
//create the Activity
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//get a reference to the button element listed in the XML layout
Button speakButton = (Button)findViewById(R.id.speak);
//listen for clicks
speakButton.setOnClickListener(this);
//check for TTS data
Intent checkTTSIntent = new Intent();
checkTTSIntent.setAction(TextToSpeech.Engine.ACTION_CHECK_TTS_DATA);
startActivityForResult(checkTTSIntent, MY_DATA_CHECK_CODE);
}
//respond to button clicks
public void onClick(View v) {
//get the text entered
EditText enteredText = (EditText)findViewById(R.id.enter);
String words = enteredText.getText().toString();
speakWords(words);
}
public void BRC (View view) {
new CountDownTimer(65000, 6000) {
public void onTick(long millisUntilFinished) {
String words1 = ("BRC will form up in" + millisUntilFinished / 6000 + " minutes");
speakWords(words1);
}
public void onFinish() {
String words2 = ("BRC will form up right away");
speakWords(words2);
}
}.start();
}
public void SRC (View view1) {
new CountDownTimer(65000, 6000) {
public void onTick(long millisUntilFinished) {
String words3 = ("SRC will form up in" + millisUntilFinished / 6000 +" minutes");
speakWords(words3);
}
public void onFinish() {
String words4=("SRC will form up right away");
speakWords(words4);
}
}.start();
}
public void Taps (View view2) {
new CountDownTimer(65000, 6000) {
public void onTick(long millisUntilFinished) {
String words5 = ("Taps will sound in" + millisUntilFinished / 6000 +" minutes");
speakWords(words5);
}
public void onFinish() {
String words6=("Attention inside and outside of barracks the status in barracks is now Taps C C Q at the beginning of this turnout there was a status check");
speakWords(words6);
}
}.start();
}
public void Penalty_Tours (View view3) {
new CountDownTimer(65000, 6000) {
public void onTick(long millisUntilFinished) {
String words7 = ("P Tees will form up in" + millisUntilFinished / 6000 +" minutes");
speakWords(words7);
}
public void onFinish() {
String words8=("P Tees will form up right away");
speakWords(words8);
}
}.start();
}
public void Colors (View view4) {
String words9 = ("Colors Colors Colors");
speakWords(words9);
}
public void PTT (View view5) {
new CountDownTimer(65000, 6000) {
public void onTick(long millisUntilFinished) {
String words10 = ("P T T will form up in" + millisUntilFinished / 6000 +" minutes");
speakWords(words10);
}
public void onFinish() {
String words11=("P T T will form up right away");
speakWords(words11);
}
}.start();
}
//speak the user text
private void speakWords(String speech) {
//speak straight away
myTTS.speak(speech, TextToSpeech.QUEUE_FLUSH, null);
}
//act on result of TTS data check
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == MY_DATA_CHECK_CODE) {
if (resultCode == TextToSpeech.Engine.CHECK_VOICE_DATA_PASS) {
//the user has the necessary data - create the TTS
myTTS = new TextToSpeech(this, this);
}
else {
//no data - install it now
Intent installTTSIntent = new Intent();
installTTSIntent.setAction(TextToSpeech.Engine.ACTION_INSTALL_TTS_DATA);
startActivity(installTTSIntent);
}
}
}
//setup TTS
public void onInit(int initStatus) {
//check for successful instantiation
if (initStatus == TextToSpeech.SUCCESS) {
if(myTTS.isLanguageAvailable(Locale.US)==TextToSpeech.LANG_AVAILABLE)
myTTS.setLanguage(Locale.US);
}
else if (initStatus == TextToSpeech.ERROR) {
Toast.makeText(this, "Sorry! Text To Speech failed...", Toast.LENGTH_LONG).show();
}
}
}
Any help would be greatly appreciated.
public void BRC(View view) {
int totaltime = 6500;
CountDownTimer mTimer = new CountDownTimer(totaltime, 6000) {
public void onTick(long millisUntilFinished) {
String words1 = ("BRC will form up in" + millisUntilFinished / 6000 + " minutes");
speakWords(words1);
}
public void onFinish() {
String words2 = ("BRC will form up right away");
speakWords(words2);
}
}.start();
void SRC() {
mTimer.cancel();
}
}
In MainActivity function ,declare a variable to define the status of each counter. In onTick() of all counters, make it check for the variable
Hope this help.
public class MainActivity extends Activity implements OnClickListener, OnInitListener {
//TTS object
private Boolean isBRCRunning = false;
private Boolean isPTTRunning = false;
private static CountDownTimer myBRC;
private static CountDownTimer myPTT;
//
//respond to button clicks
public void onClick(View v) {
// .....
// If BRC button
if(BRC button){
BRC();
isBRCRunning = true;
} else if (PTT button){
BRC();
isBRCRunning = true;
}
}
public void BRC () {
myBRC = new CountDownTimer(65000, 6000) {
public void onTick(long millisUntilFinished) {
String words1 = ("BRC will form up in" + millisUntilFinished / 6000 + " minutes");
MainActivity.logForDebug(MainActivity.TAG, words1);
// Control other timer
if(isPTTRunning){
myPTT.cancel();
isPTTRunning = false;
}
}
public void onFinish() {
String words2 = ("BRC will form up right away");
MainActivity.logForDebug(MainActivity.TAG, words2);
}
}.start();
}
public void PTT () {
myPTT = new CountDownTimer(65000, 6000) {
public void onTick(long millisUntilFinished) {
String words1 = ("BRC will form up in" + millisUntilFinished / 6000 + " minutes");
MainActivity.logForDebug(MainActivity.TAG, words1);
// Control other timers
if(isBRCRunning){
myBRC.cancel();
isBRCRunning = false;
}
}
public void onFinish() {
String words2 = ("BRC will form up right away");
MainActivity.logForDebug(MainActivity.TAG, words2);
}
}.start();
}
}
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.
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.