Display the remaining time of the handler

Question

I would like to know how to display the time remaining in my handler. When I click a button, I run my handler for x seconds, and I want to display a countdown on the screen before the end of the handler.

create a countdown timer and set the same time as the one in your handler. Here's a thread to help you create a countdown timer : https://stackoverflow.com/a/36713370/10300673 — Nikos Hidalgo, Feb 27 '19 at 16:05

score 0 · Answer 1 · answered Feb 27 '19 at 16:05

Try this:

    int time = 60;  // seconds
    final Handler handler = new Handler();
    Runnable runnable = new Runnable() {
        public void run() {
            time--;
            mTextView.setText(time + " seconds");
        }
    };
    handler.postDelayed(runnable, 1000);

score 0 · Accepted Answer · answered Feb 27 '19 at 16:51

0

official documentation

Example of showing a 30 second countdown in a text field:

new CountDownTimer(30000, 1000) {
     public void onTick(long millisUntilFinished) {
         mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
     }

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

answered Feb 27 '19 at 16:51

Thomas Mary

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It works fine thank you, last detail, if I put 5 seconds, it shows: 5, 4, 3, 2, 1 and 0. In the end it's 6 seconds. How to remove the 0 at the end? – MaximeG31 Feb 27 '19 at 17:24

score 0 · Answer 3 · answered Mar 13 '19 at 12:56

It works fine thank you, last detail, if I put 5 seconds, it shows: 5, 4, 3, 2, 1 and 0. In the end it's 6 seconds.

Maxime, as I read in your comment to Thomas Mary's answer, you want to avoid getting an extra call to onTick().

You're seeing this because the original implementation of CountDownTimer calls onTick() for the first time as soon as (without delay) the timer is started.

How to remove the 0 at the end?

For this you can use this modified CountDownTimer :

public abstract class CountDownTimer {

private final long mMillisInFuture;
private final long mCountdownInterval;
private long mStopTimeInFuture;

private boolean mCancelled = false;

public CountDownTimer(long millisInFuture, long countDownInterval) {
    mMillisInFuture = millisInFuture;
    mCountdownInterval = countDownInterval;
}

public synchronized final void cancel() {
    mCancelled = true;
    mHandler.removeMessages(MSG);
}

public synchronized final CountDownTimer start() {
    mCancelled = false;
    if (mMillisInFuture <= 0) {
        onFinish();
        return this;
    }
    mStopTimeInFuture = SystemClock.elapsedRealtime() + mMillisInFuture;
    onTick(mMillisInFuture);
    mHandler.sendMessageDelayed(mHandler.obtainMessage(MSG), mCountdownInterval);
    return this;
}

public abstract void onTick(long millisUntilFinished);

public abstract void onFinish();

private static final int MSG = 1;

private Handler mHandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
        synchronized (CountDownTimer.this) {
            if (mCancelled)
                return;
            final long millisLeft = mStopTimeInFuture - SystemClock.elapsedRealtime();
            if (millisLeft <= 0) {
                onFinish();
            } else {
                onTick(millisLeft);
                sendMessageDelayed(obtainMessage(MSG), mCountdownInterval);
            }
        }
    }
};
}

Note that you might need to adjust your implementation in onTick() method accordingly.

Display the remaining time of the handler

3 Answers3