rxjava fromcallable

import io.reactivex.rxjava3.core.Observable;
import java.util.concurrent.Callable;

public class RxJavaExample {
    public static void main(String[] args) {
        // 创建一个 Callable 对象
        Callable<Integer> callable = () -> {
            Thread.sleep(1000); // 模拟耗时操作
            return 42;
        };

        // 使用 fromCallable 将 Callable 转换为 Observable
        Observable<Integer> observable = Observable.fromCallable(callable);

        // 订阅 Observable 并处理结果
        observable.subscribe(
            result -> System.out.println("Result: " + result), // onNext 回调
            error -> System.err.println("Error: " + error),     // onError 回调
            () -> System.out.println("Completed")               // onComplete 回调
        );

        // 为了让程序不立即退出，等待一段时间
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

observable.subscribe(
    result -> System.out.println("Result: " + result),
    error -> System.err.println("Error occurred: " + error.getMessage()),
    () -> System.out.println("Completed")
);

observable
    .subscribeOn(Schedulers.io()) // 在 IO 线程执行 Callable
    .observeOn(AndroidSchedulers.mainThread()) // 在主线程接收结果
    .subscribe(result -> System.out.println("Result: " + result));