c – 如何让方法在返回之前发送信号并等待插槽？

这是从最低级别到最高级别使用的类的层次结构.

/** Controls wireless network card by commanding a software component "connman" via DBus. */
class WifiController : QObject {
Q_OBJECT

public:

    void scan();
}

/** Low level interface to network interfaces. */
class NetworkController : QObject {
    Q_OBJECT

public:

    void scan_for_wifi() {
        wifi_controller.scan();
        // When scan is finished it sends the
        // NetworkTechnology::scanFinished signal.
    }

    // Gets info from cache. This cache is updated when a `scan()` happens.
    QList<AccessPointInfo> get_available_access_points;

private:
    WifiController wifi_controller;
}

/** High level interface to network interfaces. */
class ConnectionManager {
public:
    QList<QString> get_wifi_ssids() {
        netCtrlr.scan();
        // PROBLEM HERE: How do I wait for the `scanFinished` signal here,then
        // continue execution and return the SSIDs from the recently-updated
        // cache?

        QList<AccessPointInfo> APs { netCtrlr.get_available_access_points() };
        QList<QSitrng> ssids { parseAPInfo(APs) };
        return ssids;
    }

private:
    NetworkController netCtrlr;
}

我的整个应用程序都在一个线程中. “connman”是由WifiConroller通过DBus命令的,它是一个单独的进程,所以很明显在一个单独的线程中. GUI在一个单独的进程中运行,我的应用程序通过DBus与它通信.

根据this answer的评论,QEventLoop是一个糟糕的解决方案,因为它不打算在生产中使用,而且更像是黑客攻击.