QT ping网络通断

其中 -n 为请求数，-w 为请求超时时间。为了更快获取网络状态结果，调整这两个参数即可。例如：

ping www.baidu.com -n 2 -w 500

其含义为向www.baidu.com请求两包数据，每包数据超时时间为500ms。系统调用这个命令，就能在1s内获取网络状态了。但是如果在主线程中直接调用该指令，会存在阻塞，导致界面卡顿。所以，建议通过线程来调用ping指令。
如下为示例，供参考，
networkThread.h

#ifndef NETWORKTHREAD_H
#define NETWORKTHREAD_H
 
#include <QProcess>
#include <QThread>
class networkThread: public QThread
{
    Q_OBJECT            //一定要加这个
public:
    networkThread();
    virtual void run();
    void stop();
signals:
    void signalsNetwork_States(bool state);
 
private:
    bool flagRunning;   //线程运行标志
    QProcess *network_process;
};
 
#endif // NETWORKTHREAD_H

#include "networkThread.h"
 
networkThread::networkThread()
{
    flagRunning = true;
}
 
void networkThread::run()
{
    QString network_cmd = "ping www.baidu.com -n 2 -w 500";
    QString result;
    network_process = new QProcess();    //不要加this
    while(flagRunning)
    {
        network_process->start(network_cmd);   //调用ping 指令
        network_process->waitForFinished();    //等待指令执行完毕
        result = network_process->readAll();   //获取指令执行结果
        if(result.contains(QString("TTL=")))   //若包含TTL=字符串则认为网络在线
        {
            emit signalsNetwork_States(1);  //在线
        }
        else
        {
            emit signalsNetwork_States(0); //离线
        }
        sleep(1);  //加sleep降低CPU占用率
    }
}
void networkThread::stop()
{
    flagRunning = false;
}

#ifndef WIDGET_H
#define WIDGET_H
 
#include <QWidget>
#include "networkThread.h"    //包含头文件
namespace Ui {
class Widget;
}
 
class Widget : public QWidget
{
    Q_OBJECT
public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
public slots:
    void slot_updateNetwork(bool state); //更新网络状态
 
private:
    Ui::Widget *ui;
    networkThread *netWork_thread;
};
 
#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
 
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    netWork_thread= new networkThread();
    connect(netWork_thread, SIGNAL(signalsNetwork_States(bool)), this, SLOT(slot_updateNetwork(bool)));
    netWork_thread->start(); //开启网络检测线程
}
 
Widget::~Widget()
{
    delete ui;
}
 
void Widget::slot_updateNetwork(bool state)
{
    if(state)
        ui->label->setText("在线");
    else
        ui->label->setText("离线");
}