Qt：如何獲得來自GET的響應？

Question

我在收集來自網絡請求的響應時遇到問題。 （因爲我是Qt新手）。

爲什麼我有麻煩？

我有一個請求類，它發送請求並接收響應。但是我不能得到對請求對象的父對象的響應，因爲我必須等待來自處理響應的NetworkAccessMaanager的「完成」信號。

所以我處理「完成」插槽中的響應，但我無法將信息返回到持有請求對象的父主窗口。我怎樣才能做到這一點？

下面的代碼：

主要window.cpp：

MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) 
{ 
    ui->setupUi(this); 
} 

MainWindow::~MainWindow() 
{ 
    delete ui; 
} 

void MainWindow::on_buttonLogin_clicked() 
{ 
    request->sendRequest("www.request.com"); 
} 

Request.cpp：

Request::Request() 
{ 
    oNetworkAccessManager = new QNetworkAccessManager(this); 
    QObject::connect(oNetworkAccessManager,SIGNAL(finished(QNetworkReply*)),this,SLOT(finishedSlot(QNetworkReply*))); 
} 

/* 
* Sends a request 
*/ 
QNetworkReply* Request::sendRequest(QString url) 
{ 
    QUrl httpRequest(url); 
    QNetworkRequest request; 
    request.setSslConfiguration(QSslConfiguration::defaultConfiguration()); // Set default ssl config 
    request.setUrl(httpRequest); // Set the url 
    QNetworkReply *reply = oNetworkAccessManager->get(QNetworkRequest(httpRequest)); 

    return reply; 
} 

/* 
* Runs when the request is finished and has received a response 
*/ 
void Request::finishedSlot(QNetworkReply *reply) 
{ 
     // Reading attributes of the reply 
     // e.g. the HTTP status code 
     QVariant statusCodeV = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute); 
     // Or the target URL if it was a redirect: 
     QVariant redirectionTargetUrl = 
     reply->attribute(QNetworkRequest::RedirectionTargetAttribute); 
     // see CS001432 on how to handle this 

     // no error received? 
     if (reply->error() == QNetworkReply::NoError) 
     { 
      // Reading the data from the response 
      QByteArray bytes = reply->readAll(); 
      QString jsonString(bytes); // string 

      bool ok; 
      QVariantMap jsonResult = Json::parse(jsonString,ok).toMap(); 
      if(!ok) 
      { 
       qFatal("An error occured during parsing"); 
       exit(1); 
      } 


      // Set the jsonResult 
      setJsonResult(jsonResult); 


     } 
     // Some http error received 
     else 
     { 
      // handle errors here 
     } 

     // We receive ownership of the reply object 
     // and therefore need to handle deletion. 
     delete reply; 
} 

/* 
* Set the json result so that other functions can get it 
*/ 
void Request::setJsonResult(QVariantMap jsonResult) 
{ 
    m_jsonResult = jsonResult; 
} 

/* 
* Get the json result 
* Return null if there is no result 
*/ 
QVariantMap Request::getJsonResult() 
{ 
    return m_jsonResult; 
} 

的我怎麼能做到這一點任何想法？

在此先感謝！

Answer 1

每個QNetworkReply發出finished()信號，所以你應該從request->sendRequest("www.request.com");回到了MainWindow插槽QNetworkReply*連接信號。

例：

void MainWindow::on_buttonLogin_clicked() 
{ 
    QNetworkReply *reply = request->sendRequest("www.request.com"); 
    connect(reply, SIGNAL(finished()), this, SLOT(newslot())); 
} 

void MainWindow::newslot() 
{ 
    QNetworkReply* reply = qobject_cast<QNetworkReply*>(sender()); 
    // there you can handle reply as you wish 
}