使用未声明的标识符'connect'

Question

又是我!: - [

我正在尝试在qt中编写一个简单的下载程序.它基于这个例子:http://www.ggkf.com/qt/qnetworkrequest-to-download-an-image

downloader.cpp:

void Downloader::GetImage( QString _url, QNetworkAccessManager *qnam ) {
    connect( qnam, SIGNAL( finished( QNetworkReply *) ), this, SLOT( replyFinished(   QNetworkReply * ) ) );

    QUrl url = QUrl( _url );
    QNetworkRequest request( url );

    qnam->get( request );
}

但我收到以下错误:

/Users/name/ssl/downloader.cpp:19: error: use of undeclared identifier 'connect'
connect( qnam, SIGNAL( finished( QNetworkReply *) ), this, SLOT( replyFinished( QNetworkReply * ) ) );

你能有人向我解释这个错误吗？:-)

提前致谢

Answer 1

请确保Downloader继承自QObject.

class Downloader : public QObject{

}