如何将异步任务的结果返回给android中调用它的方法的结果？

public interface AsyncTaskCallback {
    void onTaskComplete(String result);
}

public class MyAsyncTask extends AsyncTask<Void, Void, String> {
    private AsyncTaskCallback callback;

    public MyAsyncTask(AsyncTaskCallback callback) {
        this.callback = callback;
    }

    @Override
    protected String doInBackground(Void... params) {
        // 执行异步任务，返回结果
        return "异步任务结果";
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        // 执行完毕后调用回调方法
        callback.onTaskComplete(result);
    }
}

// 调用异步任务
MyAsyncTask task = new MyAsyncTask(new AsyncTaskCallback() {
    @Override
    public void onTaskComplete(String result) {
        // 处理异步任务的结果
    }
});
task.execute();

public class MyAsyncTask extends AsyncTask<Void, Void, String> {
    private Handler handler;

    public MyAsyncTask(Handler handler) {
        this.handler = handler;
    }

    @Override
    protected String doInBackground(Void... params) {
        // 执行异步任务，返回结果
        return "异步任务结果";
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);
        // 发送结果到主线程
        Message message = Message.obtain();
        message.obj = result;
        handler.sendMessage(message);
    }
}

// 在主线程中创建Handler并处理结果
Handler handler = new Handler(Looper.getMainLooper()) {
    @Override
    public void handleMessage(Message msg) {
        String result = (String) msg.obj;
        // 处理异步任务的结果
    }
};

// 调用异步任务
MyAsyncTask task = new MyAsyncTask(handler);
task.execute();

Observable<String> observable = Observable.create(new Observable.OnSubscribe<String>() {
    @Override
    public void call(Subscriber<? super String> subscriber) {
        // 执行异步任务，调用subscriber.onNext(result)发送结果
        subscriber.onNext("异步任务结果");
        subscriber.onCompleted();
    }
});

Subscriber<String> subscriber = new Subscriber<String>() {
    @Override
    public void onNext(String result) {
        // 处理异步任务的结果
    }

    @Override
    public void onCompleted() {}

    @Override
    public void onError(Throwable e) {}
};

// 调用异步任务
observable.subscribeOn(Schedulers.io())
    .observeOn(AndroidSchedulers.mainThread())
    .subscribe(subscriber);