Question

有没有办法使用Qt检查电缆是否未拔下？

我知道我要联系的Ip adress，起初我想在ping request上做Ip Adress，但对于这个简单的任务来说似乎太复杂了。

所以我想也许，有一个简单的功能可以在QNetwork library中执行此操作。

我在互联网上搜索，但所有解决方案都没有测试一个特定的IP。

感谢您的帮助。

Answer 1

有没有办法检查是否使用Qt拔掉了电缆？

您可以使用QNetworkSession：

为指定的界面实现此目的

QNetworkConfigurationManager nwManager (this);
for (;;QThread::sleep (1) ) {
    bool isConfigurationFound {false};
    for (auto & configuration : nwManager.allConfigurations (/*QNetworkConfiguration::Active*/) ) {
        // Name depends on the environment: "Wired connection 1", "McDonaldsFreeWiFi", "Home", "eth0", "eth1", etc...
        if (isConfigurationFound = (configuration.name () == "eth0") ) {
            QNetworkSession session (configuration, this);
            session.open ();
            session.waitForOpened (/*timeout*/);

            qDebug () << "Session info:";
            qDebug () << "- usage: " << (session.isOpen () ? "Opened" : "Closed");
            qDebug () << "- state: " << (session.state  () == QNetworkSession::Connected ? "Connected" : "Not connected");

            break;
        }
    }
    qDebug () << (isConfigurationFound ? "" : "Configuration not found.");
}

如果您使用连接电缆启动此代码，则会获得：

"Session info:" 
"- usage: Opened;" 
"- state: Connected;"

如果拔下电缆，你会得到：

"Session info:" 
"- usage: Closed" 
"- state: Not connected"

以下是完整示例（也可在GitLab处获得）：

CMakeLists.txt

cmake_minimum_required (VERSION 2.8.8)
project (NaQt)
find_package (Qt5Network)
set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

set (NaQt_SOURCES ${PROJECT_SOURCE_DIR}/main.cpp)
set (NaQt_HEADERS ${PROJECT_SOURCE_DIR}/NetworkAnalyzer.h)
qt5_wrap_cpp (NaQt_HEADERS_MOC ${NaQt_HEADERS})

add_executable (
    naqt
    ${NaQt_SOURCES}
    ${NaQt_HEADERS_MOC}
)
target_link_libraries (
    naqt
    Qt5::Core
    Qt5::Network
)

main.cpp

#include <QtCore>
#include "NetworkAnalyzer.h"

int main (int argc, char * argv [])
{
    QCoreApplication application (argc, argv);
    NetworkAnalyzer networkAnalyzer (& application);
    return application.exec ();
}

NetworkAnalyzer.h

#ifndef QT_NETWORK_ANALYZER_H
#define QT_NETWORK_ANALYZER_H

#include <QThread>
#include <QNetworkConfigurationManager>
#include <QNetworkSession>
#include <QDebug>

class NetworkAnalyzer : public QObject
{
Q_OBJECT

public:
    NetworkAnalyzer (QObject * parent = nullptr)
    {
        QNetworkConfigurationManager nwManager (this);
        for (;;QThread::sleep (1) ) {
            bool isConfigurationFound {false};
            for (auto & configuration : nwManager.allConfigurations (/*QNetworkConfiguration::Active*/) ) {
                // Name depends on the environment: "Wired connection 1", "McDonaldsFreeWiFi", "Home", "eth0", "eth1", etc...
                if (isConfigurationFound = (configuration.name () == "eth0") ) {
                    QNetworkSession session (configuration, this);
                    session.open ();
                    session.waitForOpened (/*timeout*/);

                    qDebug () << "Session info:";
                    qDebug () << "- usage: " << (session.isOpen () ? "Opened" : "Closed");
                    qDebug () << "- state: " << (session.state  () == QNetworkSession::Connected ? "Connected" : "Not connected");

                    break;
                }
            }
            qDebug () << (isConfigurationFound ? "" : "Configuration not found.");
        }
    }
};

#endif//QT_NETWORK_ANALYZER_H

Answer 2

尝试在预定义端口上打开指定IP地址的套接字：

QTcpSocket tester;

tester.connectToHost(address, port);

if(tester.waitForConnected(3000)) {
    //Remote host is online
} else {
    //Remote host is offline
}

Answer 3

使用QT的QNetworkAccessManager类，该类提供networkAccessibleChanged信号并连接一个插槽

connect(&networkAccessManager, SIGNAL(networkAccessibleChanged(QNetworkAccessManager::NetworkAccessibility)), this, SLOT(onNetworkAccessibilityChanged(QNetworkAccessManager::NetworkAccessibility)));

它会在断开以太网电缆时发出信号，告诉您

使用Qt测试本地连接

3 个答案: