Countdown to Android verification code and countdown to Android Verification Code

Countdown to Android verification code and countdown to Android Verification Code

Android provides a convenient android. OS. CountDownTimer class for the verification code countdown.

Usage:

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

OnTick interval callback onfinish countdown completion callback

From the source code, we can see that its implementation is mainly implemented through sendMessageDelayed. Its main logic is as follows:

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 if (millisLeft < mCountdownInterval) {                    // no tick, just delay until done                    sendMessageDelayed(obtainMessage(MSG), millisLeft);                } else {                    long lastTickStart = SystemClock.elapsedRealtime();                    onTick(millisLeft);                    // take into account user's onTick taking time to execute                    long delay = lastTickStart + mCountdownInterval - SystemClock.elapsedRealtime();                    // special case: user's onTick took more than interval to                    // complete, skip to next interval                    while (delay < 0) delay += mCountdownInterval;                    sendMessageDelayed(obtainMessage(MSG), delay);                }            }        }    };

You can perform related logic when you perform some scheduled operations in the future.