qt异步通信

在Qt与Http通信的时候，会根据不同的情况使用同步或者异步的方式进行数据请求。

同步，即发送Http请求之后，会一直等待服务器返回的数据，接收到数据之前，程序一直阻塞。

异步，即发送Http请求之后，程序可以继续往下执行，接收到服务器返回的数据时自动调用其对应的槽函数处理数据。

Tcp异步编程的核心就是Qt的信号槽机制，通过关联对应的信号，等信号来了之后在做出相应的响应。显然，异步操作是可以主线程(GUI)中使用，因为它不会阻塞主线程,这也是与同步根本的区别。下面展示tcp异步编程的基本步骤，包含客户端和服务端。

头文件：

public slots:
    void slotCoreTcpReceiveAll(const QString &ip, const QString &sCD, const QVariant &jsonData, int number, bool isError, const QVariantMap &map) override;

 源文件（注意绑定槽函数中的操作）：

    ui->toolbar->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);//样式：文本在图标下面
    //toolBar
    QAction * ac = Q_NULLPTR;
    {
        ac = new  QAction(QIcon(StyleObject::init()->getCurrentSkinDirPath()+"/images/upload"),tr("Upload"),this);
        ui->toolbar->addAction(ac);
//绑定槽函数！！！！！！！！！！！！！！！！
        connect(ac,&QAction::triggered,this,[=](bool checked){
            uploadAudioFile();
        });

        ac = new  QAction(QIcon(StyleObject::init()->getCurrentSkinDirPath()+"/images/refresh_normal"),tr("Refresh"),this);
        ui->toolbar->addAction(ac);
        connect(ac,&QAction::triggered,this,[=](bool checked){
            UiClass::init()->showWaittingWidget(tr("refresh..."),this);
            refreshAudioList();
        });

        ui->toolbar->addSeparator();

        ac = new  QAction(QIcon(StyleObject::init()->getCurrentSkinDirPath()+"/images/delete_hover"),tr("Delete"),this);
        ui->toolbar->addAction(ac);
        connect(ac,&QAction::triggered,this,[this](){
            deleteAudioFile();
        });
    }

uploadAudioFile中发送请求

void AudioManagementView::uploadAudioFile()
{
    QString filePath = QFileDialog::getOpenFileName(this,tr("Audio file"),PublicClass::init()->getSoundsPath(),"*.wav");

    if(filePath.isEmpty()){
        return;
    }
    QFileInfo fileInfo(filePath);
//    SCDebug<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~filePath:"<<filePath;
    QString sCompleteBaseName = fileInfo.completeBaseName();
    if(PublicClass::init()->isChinese(sCompleteBaseName)){
        slotMessage(QString(tr("Chinese filename is not supported")),SCToastr::E_Warning);
        return;
    }
    if(sCompleteBaseName.toLocal8Bit().size()>20){
        slotMessage(QString(tr("File name's length larger than 20 bytes are not supported")),SCToastr::E_Warning);
        return;
    }
    QFile file(fileInfo.filePath());
    if(!file.open(QIODevice::ReadOnly)){
        slotMessage(QString(tr("Failed to open audio file:")).arg(file.errorString()),SCToastr::E_Warning);
        return;
    }
    QByteArray b = file.readAll();
    file.close();

    QVariantMap jsonMap;
    jsonMap.insert("type","uploadFile");
    jsonMap.insert("filePath", AdvancedViewCommon::init()->_audioPath + "/" + fileInfo.fileName());
//    SCDebug<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~jsonMap"<<jsonMap;
    //发送请求
    RobotManager::init()->sendData(RobotInterface::E_CoreTcp,jsonMap,b,"robot_core_operate_req","",E_AudioManagement);

    UiClass::init()->releaseWaittingWidget(this);
    refreshAudioList();
}

与请求对应的函数（接收了所有数据）

void AudioManagementView::slotCoreTcpReceiveAll(const QString &ip, const QString &sCD, const QVariant &jsonData , int number, bool isError,const QVariantMap &map)
{
    Q_UNUSED(ip)
    if(number != E_AudioManagement) return;
    if(isError){
        UiClass::init()->releaseWaittingWidget(this);
        UiClass::init()->showToastr(QString(("%1")).arg(jsonData.toString()),SCToastr::E_Warning,this);
        return;
    }
    auto type = map.value("jsonData").toMap().value("type").toString();
    if(sCD == "robot_core_operate_req"){
        if("uploadFile"==type){
            refreshAudioList();
        }else if("getFileList"==type){
            QString jsonString = jsonData.toString();
            QJsonDocument jsonDoc = QJsonDocument::fromJson(jsonString.toUtf8());
            QVariant revData = jsonDoc.toVariant();
            getFileList_var=revData.toList();
            refreshTable(revData.toList());
            UiClass::init()->releaseWaittingWidget(this);
        }else if("downloadFile"==type){
            downloadFile_var = jsonData.toByteArray();
        }
    }else if(sCD == "robot_core_audiodriverlist_req"){
//        QJsonDocument jsonDoc = QJsonDocument::fromJson(jsonData.toByteArray());
//        QJsonObject nobj = QJsonObject(jsonDoc.object());
//        QVariantMap var = nobj.toVariantMap();
//        SCDebug<<"~~~~~~~~~~~~~~~~~~~~~~~~~jsondata::"<<jsonData;
    }

}