将CountDownTimer取消功能转换为RxJava

import io.reactivex.Observable;
import io.reactivex.disposables.Disposable;
import io.reactivex.schedulers.Schedulers;

public class CountdownTimerRxJava {
    private Disposable disposable;

    public void startCountdown(long duration) {
        Observable<Long> observable = Observable.create(emitter -> {
            long count = duration;
            while (count >= 0 && !emitter.isDisposed()) {
                emitter.onNext(count);
                count--;
                Thread.sleep(1000); // 每隔1秒发射一个事件
            }
            emitter.onComplete();
        });

        disposable = observable
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(
                        count -> {
                            // 处理倒计时事件
                            // 更新UI等操作
                        },
                        throwable -> {
                            // 处理异常
                        },
                        () -> {
                            // 倒计时完成
                        }
                );
    }

    public void cancelCountdown() {
        if (disposable != null && !disposable.isDisposed()) {
            disposable.dispose();
        }
    }
}