CountdownTimer完成时如何通知Observable

我有一个自定义的Android TextView，通过CountDownTimer显示游戏中剩余的时间

class CountdownTextView(context: Context, attrs: AttributeSet) : TextView(context, attrs) { private lateinit var countDownTimer: CountDownTimer private lateinit var onFinishObservable: Observable<Unit> fun setTime(initTime: Int) { this.text = "$initTime:00" countDownTimer = object : CountDownTimer((initTime *1000).toLong(), 1000) { override fun onTick(millisUntilFinished: Long) { val minutes = millisUntilFinished / 60000 val seconds = (millisUntilFinished % 60000) / 1000 if (seconds / 10 > 0) { text = "$minutes:${(millisUntilFinished % 60000) / 1000}" } else { text = "$minutes:0${(millisUntilFinished % 60000) / 1000}" } } override fun onFinish() { } } fun startCountdown() { countDownTimer.start() } } 

如何在调用countDownTimer的onFinish（）方法时设置一个发出值的observable？ 我需要这样做，以便在主要的活动中，我可以订阅这个可观察的，并在倒数计时器到期时执行必要的操作。

Answer 1

你可以提供一个主题 。

 val onFinishObservable = CompletableSubject.create() override fun onFinish() { onFinishObservable.onComplete() } 

或者你可以使用Rx来代替CountDownTimer 。

 fun countDownTimer( time: Long, timeUnit: TimeUnit = TimeUnit.MILLISECONDS, tick: Long = 1, tickUnit: TimeUnit = TimeUnit.MILLISECONDS ): Observable<Long> { val timeNanos = timeUnit.toNanos(time).also { require(it >= 0) } val tickNanos = tickUnit.toNanos(tick).also { require(it > 0) } val ticks = timeNanos / tickNanos return Observable .intervalRange( 1L, ticks, timeNanos % tickNanos, tickNanos, TimeUnit.NANOSECONDS) .map { ticks - it } .startWith(ticks) } fun start(time: Long, timeUnit: TimeUnit = TimeUnit.SECONDS): Completable { timerSubscription?.dispose() val timer = countDownTimer(time, timeUnit, tickUnit = TimeUnit.SECONDS) timerSubscription = timer.subscribe { text = String.format("%d:%02d", it / 60, it % 60) } return timer.ignoreElements() } 

无论哪种方式，来电者可以订阅该Completable 。