Android中两种实现倒计时的方法

1.rxjava

public static Observable countdown(int time) {
if (time < 0) time = 0;
final int countTime = time;
return Observable.interval(0, 1, TimeUnit.SECONDS)
.subscribeOn(AndroidSchedulers.mainThread())
.observeOn(AndroidSchedulers.mainThread())
.map(new Function() {
@Override
public Integer apply(@NonNull Long increaseTime) throws Exception {
Log.d("RxCountDown", "increaseTime.intValue():" + increaseTime.intValue());
return countTime - increaseTime.intValue();
}
})
.take(countTime + 1);
}
private void countdown2() {
RxCountDown.countdown(120)
.doOnSubscribe(new Consumer() {
@Override
public void accept(Disposable disposable) throws Exception {
Log.d("MainActivity", "即时开始");
startTime = System.currentTimeMillis();
}
})
.subscribe(new Observer() {
@Override
public void onSubscribe(@NonNull Disposable d) {
Log.d("MainActivity", "记时开始");
}
@Override
public void onNext(@NonNull Integer integer) {
Log.d("MainActivity", "当前时间"+integer);
}
@Override
public void onError(@NonNull Throwable e) {
}
@Override
public void onComplete() {
Log.d("MainActivity", "计时结束");
Log.d("MainActivity", "System.currentTimeMillis()-startTime:" + (System.currentTimeMillis() - startTime)/1000.0);
}
});
}

2、sdk25中的CountDownTimer

private void countDown() {
mStartTime = System.currentTimeMillis();
index = 120;
new CountDownTimer(120*1000,1000){
@Override
public void onTick(long millisUntilFinished) {
Log.d("MainActivity", "l:" + Math.round((millisUntilFinished/1000.0)));
Log.d("MainActivity", "index:" + (index--));
}
@Override
public void onFinish() {
Log.d("MainActivity", "index:" + 0);
long endTime = System.currentTimeMillis();
Log.d("MainActivity", "endTime-mStartTime:" + (endTime - mStartTime)/1000.0);
}
}.start();
}

以上两种倒计时的时间差都是毫秒级的，区别在于第二种不能取到最后一秒的，这个在onFinish处理就好
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