版权声明:本文为luoyong原创文章,转载请注明出处!https://blog.csdn.net/luoyong_blog https://blog.csdn.net/luoyong_blog/article/details/84256446
这是项目中用到的倒计时工具类,记录于此。
/**
* @Author: luoyong
* 2018/2/28 14:35
* @Description:倒计时工具类
*/
import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;
/* The calls to {@link #onTick(long)} are synchronized to this object so that
* one call to {@link #onTick(long)} won't ever occur before the previous
* callback is complete. This is only relevant when the implementation of
* {@link #onTick(long)} takes an amount of time to execute that is significant
* compared to the countdown interval.
*/
public abstract class CountDownTimerUtil {
/**
* Millis since epoch when alarm should stop.
*/
private long mMillisInFuture;
/**
* The interval in millis that the user receives callbacks
*/
private long mCountdownInterval;
private long mStopTimeInFuture;
private boolean mCancelled = false;
/**
* @param millisInFuture The number of millis in the future from the call
* to {@link #start()} until the countdown is done and {@link #onFinish()}
* is called.
* @param countDownInterval The interval along the way to receive
* {@link #onTick(long)} callbacks.
*/
public CountDownTimerUtil(long millisInFuture, long countDownInterval) {
mMillisInFuture = millisInFuture;
mCountdownInterval = countDownInterval;
}
public final void setCountdownInterval(long countdownInterval) {
mCountdownInterval = countdownInterval;
}
public final void setMillisInFuture(long millisInFuture) {
mHandler.removeMessages(MSG);
mMillisInFuture = millisInFuture;
}
/**
* Cancel the countdown.
*
* Do not call it from inside CountDownTimer threads
*/
public final void cancel() {
mHandler.removeMessages(MSG);
mCancelled = true;
}
/**
* Start the countdown.
*/
public synchronized final CountDownTimerUtil start() {
if (mMillisInFuture <= 0) {
onFinish();
return this;
}
mStopTimeInFuture = SystemClock.elapsedRealtime() + mMillisInFuture;
mHandler.sendMessage(mHandler.obtainMessage(MSG));
mCancelled = false;
return this;
}
/**
* Callback fired on regular interval.
* @param millisUntilFinished The amount of time until finished.
*/
public abstract void onTick(long millisUntilFinished);
/**
* Callback fired when the time is up.
*/
public abstract void onFinish();
private static final int MSG = 1;
// handles counting down
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
synchronized (CountDownTimerUtil.this) {
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;
if (!mCancelled) {
sendMessageDelayed(obtainMessage(MSG), delay);
}
}
}
}
};
}
项目中我主要用在了音乐播放器的定时关闭功能上。