[英]slot error using QNetworkAccessManager
I am trying to implement a basic http connection http://developer.nokia.com/community/wiki/Creating_an_HTTP_network_request_in_Qt into Qt but I have difficultly implementing the slot. 我正在尝试将基本的http连接http://developer.nokia.com/community/wiki/Creating_an_HTTP_network_request_in_Qt实现到Qt中,但是我很难实现该插槽。 I am a Qt novice. 我是Qt新手。
C:\\Qt5\\Tools\\QtCreator\\bin\\miniHTTP\\main.cpp:10: error: request for member 'Test' in 'mTest', which is of non-class type 'coreEng()' mTest.Test(); C:\\ Qt5 \\ Tools \\ QtCreator \\ bin \\ miniHTTP \\ main.cpp:10:错误:请求'mTest'中的成员'Test',该成员是非类类型的'coreEng()'mTest.Test();
//main.cpp //main.cpp
#include <QCoreApplication>
#include <coreeng.h>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
coreEng mTest;
mTest.Test();
return a.exec();
}
//coreeng.h //coreeng.h
#ifndef COREENG_H
#define COREENG_H
#include <QDebug>
#include <QObject>
#include <QNetworkAccessManager>
class coreEng : public QObject
{
Q_OBJECT
public:
explicit coreEng(QObject *parent = 0);
void Test();
private slots:
public slots:
void connect();
void url();
void finishedSlot();
private:
QNetworkAccessManager* nam;
};
#endif // COREENG_H
//coreeng.cpp //coreeng.cpp
#include "coreeng.h"
#include <QNetworkAccessManager>
#include <QUrl>
#include <QNetworkRequest>
#include <QNetworkReply>
#include <QImageReader>
coreEng::coreEng(QNetworkReply* parent) :
QObject(parent)
{
}
void coreEng::Test();
void coreEng::connect(){
QObject::connect(nam, SIGNAL(finished(QNetworkReply*)),
this, SLOT(finishedSlot(QNetworkReply*)));
}
void coreEng::url(){
QUrl url("http://www.forum.nokia.wiki");
QNetworkReply* reply = nam->get(QNetworkRequest(url));
}
void coreEng::finishedSlot(QNetworkReply* reply){
QVariant statusCodeV = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
QVariant redirectionTargetUrl = reply->attribute(QNetworkRequest::RedirectionTargetAttribute);
if (reply->error() == QNetworkReply::NoError)
{
QImageReader imageReader(reply);
QImage pic = imageReader.read();
QByteArray bytes = reply->readAll(); // bytes
QString string(bytes); // string
}
else
{
}
delete reply;
}
You have declared void Test();
您已声明void Test();
as a member function in the header file and have not implemented it in the cpp file. 作为头文件中的成员函数,而尚未在cpp文件中实现。 You should implement it : 您应该实现它:
void coreEng::Test()
{
...
}
In addition to other problems already described, your implementation of finished slot doesn't have the same signature of as the function definition. 除了已经描述的其他问题之外,您完成的插槽实现与函数定义的签名不同。 In your .h file you have: 在您的.h文件中,您具有:
void finishedSlot();
Whereas your .cpp has: 而您的.cpp具有:
void finishedSlot(QNetworkReply *reply) {
/*code here*/
}
So to summarise: 总结一下:
Add an implementation of your test function: 添加测试功能的实现:
void coreEng::Test() { / code here / } 无效coreEng :: Test(){/ 代码在这里 /}
Fix the signature of your constructor so that .cpp and .h files agree: 修复构造函数的签名,以使.cpp和.h文件一致:
coreEng::coreEng(QObject* parent) : QObject(parent) { / code here / } coreEng :: coreEng(QObject * parent):QObject(parent){/ 代码在这里 /}
Fix the signature of your finishedSlot so that .cpp and .h files agree: 修复您的finishSlot的签名,以使.cpp和.h文件一致:
void finishedSlot(QNetworkReply *reply); 无效finishSlot(QNetworkReply * reply);
These changes will at least get you to the stage that you're compiling successfully. 这些更改至少将使您进入编译成功的阶段。
One problem is you are running into the most vexing parse: http://en.wikipedia.org/wiki/Most_vexing_parse 一个问题是您遇到了最烦人的解析: http : //en.wikipedia.org/wiki/Most_vexing_parse
Change 更改
coreEng mTest();
to 至
coreEng mTest;
A second problem is your constructor in coreeng.cpp has the wrong signature 第二个问题是您在coreeng.cpp中的构造函数签名错误
Change: 更改:
coreEng::coreEng(QNetworkReply*) :
QObject(parent)
to 至
coreEng::coreEng(QObject* parent) :
QObject(parent)
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