How to Make a Countdown Timer in Android

How to make a countdown timer in Android?

As shown in the documentation for CountDownTimer:

new CountDownTimer(30000, 1000) {

    public void onTick(long millisUntilFinished) {
        mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
        // logic to set the EditText could go here
    }

    public void onFinish() {
        mTextField.setText("done!");
    }

}.start();

How to create a simple countdown timer in Kotlin?

You can use Kotlin objects:

val timer = object: CountDownTimer(20000, 1000) {
    override fun onTick(millisUntilFinished: Long) {...}

    override fun onFinish() {...}
}
timer.start()

How to make Countdown timer to show same time in all Activities

Use the single instance of your CounterClass throughout all the Activities/Fragments

Use static method to initialize getInstance and retrieve values getFormatedTime().

public class CounterClass  extends CountDownTimer{

private static String hms;
private static CounterClass instance;

private CounterClass(long millisInFuture, long countDownInterval){
    super(millisInFuture,countDownInterval);
}

public static CounterClass  initInstance(long millisInFuture, long countDownInterval){
    if(instance==null){
        instance =  new CounterClass(millisInFuture,countDownInterval);
    }
    return instance;
}

public static CounterClass  getInstance() throws Exception{
    if(instance==null){
        throw new Exception("Parameters not initialized. Initiate with initInstance");
    }else{
        return instance;
    }
}

public static String getFormatedTime(){
    return hms;
}
@Override
public void onTick(long l) {

    long millis= l;
    hms= String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(millis),
            TimeUnit.MILLISECONDS.toMinutes(millis) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)),
            TimeUnit.MILLISECONDS.toSeconds(millis) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis))
    );
}
@Override
public void onFinish() {

}
}

I have modified the code.

Inorder to initiate the CounterClass, do the following.

CounterClass counterClass = CounterClass.initInstance(180000, 1000);
counterClass.start();

For accessing the previous value

try {
      CounterClass counterClass = CounterClass.getInstance();
      Log.i("TAG 222", counterClass.getFormatedTime());
     } catch (Exception e) {
       e.printStackTrace();
       // counter class is not initiated , access initInstance
     }

As android.os.CountDownTimer does not have default constructor, this is the way we can achieve your requirement

How to Countdown to a day using Android CountDownTimer

This is exactly how you do it

UPDATE 3

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.your_layout);

    TextView tv_countdown = (TextView) findViewById(R.id.your_textview_id);

    Calendar start_calendar = Calendar.getInstance();
    Calendar end_calendar = Calendar.getInstance();

    long start_millis = start_calendar.getTimeInMillis(); //get the start time in milliseconds
    long end_millis = end_calendar.getTimeInMillis(); //get the end time in milliseconds
    long total_millis = (end_millis - start_millis); //total time in milliseconds
    end_calendar.set(2015, 10, 6); // 10 = November, month start at 0 = January

    //1000 = 1 second interval
    CountDownTimer cdt = new CountDownTimer(total_millis, 1000) {
        @Override
        public void onTick(long millisUntilFinished) {
            long days = TimeUnit.MILLISECONDS.toDays(millisUntilFinished);
            millisUntilFinished -= TimeUnit.DAYS.toMillis(days);

            long hours = TimeUnit.MILLISECONDS.toHours(millisUntilFinished);
            millisUntilFinished -= TimeUnit.HOURS.toMillis(hours);

            long minutes = TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished);
            millisUntilFinished -= TimeUnit.MINUTES.toMillis(minutes);

            long seconds = TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished);

            tv_countdown.setText(days + ":" + hours + ":" + minutes + ":" + seconds); //You can compute the millisUntilFinished on hours/minutes/seconds
        }

        @Override
        public void onFinish() {
            tv_countdown.setText("Finish!");
        }
    };
    cdt.start();
}

Timers in Android Studio using CountDownTimer

I have some source code similar to your questions just implement your project.

Init Variables

private static final long START_TIME_IN_MILLIS = 600000;
private TextView mTextViewCountDown;
private Button mButtonStartPause;
private Button mButtonReset;
private CountDownTimer mCountDownTimer;
private boolean mTimerRunning;
private long mTimeLeftInMillis = START_TIME_IN_MILLIS;

onCreate

//Init
    mTextViewCountDown = findViewById(R.id.text_view_countdown);
    mButtonStartPause = findViewById(R.id.button_start_pause);
    mButtonReset = findViewById(R.id.button_reset);
    mButtonStartPause.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (mTimerRunning) {
                pauseTimer();       //pauseFunction
            } else {
                startTimer();       //StartFunction
            }
        }
    });



mButtonReset.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                resetTimer();       // resetFunction
            }
        });
        updateCountDownText();      //updateEverySecond

startTimer()

mCountDownTimer = new CountDownTimer(mTimeLeftInMillis, 1000) {
        @Override
        public void onTick(long millisUntilFinished) {
            mTimeLeftInMillis = millisUntilFinished;
            updateCountDownText();
        }
        @Override
        public void onFinish() {
            mTimerRunning = false;
            mButtonStartPause.setText("Start");
            mButtonStartPause.setVisibility(View.INVISIBLE);
            mButtonReset.setVisibility(View.VISIBLE);
        }
    }.start();
    mTimerRunning = true;
    mButtonStartPause.setText("pause");
    mButtonReset.setVisibility(View.INVISIBLE);

pauseTimer()

    mCountDownTimer.cancel();
    mTimerRunning = false;
    mButtonStartPause.setText("Start");
    mButtonReset.setVisibility(View.VISIBLE);

resetTimer()

    mTimeLeftInMillis = START_TIME_IN_MILLIS;
    updateCountDownText();
    mButtonReset.setVisibility(View.INVISIBLE);
    mButtonStartPause.setVisibility(View.VISIBLE);

updateCountDownText()

    int minutes = (int) (mTimeLeftInMillis / 1000) / 60;
    int seconds = (int) (mTimeLeftInMillis / 1000) % 60;
    String timeLeftFormatted = String.format(Locale.getDefault(), "%02d:%02d", minutes, seconds);
    mTextViewCountDown.setText(timeLeftFormatted);

and Finally XML

    android:id="@+id/text_view_countdown"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:text="00:00"
    android:textColor="@android:color/black"
    android:textSize="60sp" />
    android:id="@+id/button_start_pause"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/text_view_countdown"
    android:layout_centerHorizontal="true"
    android:text="start" />
    android:id="@+id/button_reset"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/text_view_countdown"
    android:layout_marginStart="11dp"
    android:layout_toEndOf="@+id/button_start_pause"
    android:text="reset"
    android:visibility="invisible"
    tools:visibility="visible" />

How to Show Countdown timer in HH:MM:SS (Hours : Minutes : Seconds)

It's helpful for you

 private void startTimer(int noOfMinutes) {
        CountDownTimer  countDownTimer = new CountDownTimer(noOfMinutes, 1000) {
        public void onTick(long millisUntilFinished) {
            long millis = millisUntilFinished;
            //Convert milliseconds into hour,minute and seconds
            String hms = String.format("%02d:%02d:%02d", 
            TimeUnit.MILLISECONDS.toHours(millis), 
            TimeUnit.MILLISECONDS.toMinutes(millis) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)), TimeUnit.MILLISECONDS.toSeconds(millis) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis)));
            countdownTimerText.setText(hms);//set text
        }
        public void onFinish() {
            countdownTimerText.setText("TIME'S UP!!"); //On finish change timer text
        }
    }.start();

Edited

//1584700200 is timestamp in milii seconds (Friday, March 20, 2020 10:30:00 AM) 
  //1000(1sec) is time interval to call onTick method

  new CountDownTimer(1584700200, 1000){

        @Override

        public void onTick(long millisUntilFinished) {
            long millis = millisUntilFinished;
            String hms = String.format("%02d:%02d:%02d:%02d",
            TimeUnit.HOURS.toDays(TimeUnit.MILLISECONDS.toHours(millis)),
            (TimeUnit.MILLISECONDS.toHours(millis) - 
            TimeUnit.DAYS.toHours(TimeUnit.MILLISECONDS.toDays(millis))), 
            (TimeUnit.MILLISECONDS.toMinutes(millis) - 
            TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis))), (TimeUnit.MILLISECONDS.toSeconds(millis) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis))));
            countdownTimerText.setText(hms);//set text 
        }

        @Override

        public void onFinish() {
            /*clearing all fields and displaying countdown finished message          */

            countdownTimerText.setText("Count down completed");
        }
    }.start();
}

Kotlin

private fun countDown() {
    val countDownTimer = object : CountDownTimer(1584700200, 1000) {
        override fun onTick(p0: Long) {
            val millis: Long = p0
            val hms = String.format(
                "%02d:%02d:%02d:%02d",
                TimeUnit.HOURS.toDays(TimeUnit.MILLISECONDS.toDays(millis)),
                (TimeUnit.MILLISECONDS.toHours(millis) - TimeUnit.DAYS.toHours(
                    TimeUnit.MILLISECONDS.toDays(
                        millis
                    )
                )),
                (TimeUnit.MILLISECONDS.toMinutes(millis) -
                        TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis))),
                (TimeUnit.MILLISECONDS.toSeconds(millis) - TimeUnit.MINUTES.toSeconds(
                    TimeUnit.MILLISECONDS.toMinutes(millis)
                ))
            )

            System.out.println("Time : " + hms)
            countdownTimerText.setText(hms);//set text
        }

        override fun onFinish() {
            /*clearing all fields and displaying countdown finished message          */
            countdownTimerText.setText("Count down completed");
            System.out.println("Time up")
        }
    }
    countDownTimer.start()
}

Count down timer showing negative number error android

I think the problem might be that startTimer() could be called multiple times. mTimer will be overwritten with a new timer. And the old timer will keep running forever, because even if the old timer reaches 0 that old timer will then cancel the new timer by calling stopTimer(). A solution might be to call mTimer.cancel() (or stopTimer()) at the start of startTimer()

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