QObject::connect: No such signal QThread::ThreadsMiniature::drowMiniature(QImage)

haifisch

What am I doing wrong ?
threadsminiature.h

#ifndef THREADSMINIATURE_H
#define THREADSMINIATURE_H

#include <QThread>
#include <QImageReader>
#include "mainwindow.h"

class ThreadsMiniature : public QThread
{
public:
    explicit ThreadsMiniature(QObject *parent=0, QString Path="");

    void run();
    QString _Path;
signals:
    QImage drowMiniature(QImage image) {return image;}

private:
    QString name; 
};

threadsminiature.cpp

#include "threadsminiature.h"

ThreadsMiniature::ThreadsMiniature(QObject *parent, QString Path) :
    QThread(parent),
    _Path(Path)
{

}

void ThreadsMiniature::run()
{
    int icoWidth    = 200;
    int icoHeight    = 200;

    QImageReader imageReader(_Path);

    QSize size;
    int image_width;
    int image_height;

    if (imageReader.supportsOption(QImageIOHandler::Size))
    {
        size = imageReader.size();
        image_width = size.width();
        image_height = size.height();
    }

    double ratio = (double)image_width / (double)image_height;
    if (ratio >= 1)
    {
        image_width = icoWidth;
        image_height = image_width / ratio;
    } else {
        image_height = icoHeight;
        image_width = image_height * ratio;
    }

    imageReader.setScaledSize(QSize(image_width, image_height));

    emit drowMiniature(imageReader.read());

}

mainwindow.cpp

ThreadsMiniature *threadB = new ThreadsMiniature(this,imagePathListCopy.at(i));
                connect(threadB, SIGNAL(ThreadsMiniature::drowMiniature(QImage)),this,SLOT(MainWindow::Miniature(QImage)));
                threadB->start();

void MainWindow::Miniature (QImage image) {
    qDebug()<<image<<"_+___+";
        item_one = new QStandardItem();
        item_one->setData(QVariant(QPixmap::fromImage(image)), Qt::DecorationRole);
        model->setItem(rowTableDisk, 2, item_one);
}

I receive:

QObject::connect: No such signal QThread::ThreadsMiniature::drowMiniature(QImage)
QObject::connect: (receiver name: 'MainWindow')
QObject::connect: No such signal QThread::ThreadsMiniature::drowMiniature(QImage)
QObject::connect: (receiver name: 'MainWindow')

kshegunov

You have forgotten the Q_OBJECT macro.

haifisch

@kshegunov said in QObject::connect: No such signal QThread::ThreadsMiniature::drowMiniature(QImage):

Q_OBJECT

Yes, I forgot Q_OBJECT. Thank you so much.
Now Errors:

threadsminiature.obj:-1: ошибка: LNK2001: unresolved external symbol "public: virtual struct QMetaObject const * __cdecl ThreadsMiniature::metaObject(void)const " (?metaObject@ThreadsMiniature@@UEBAPEBUQMetaObject@@XZ)

threadsminiature.obj:-1: ошибка: LNK2001: unresolved external symbol "public: virtual void * __cdecl ThreadsMiniature::qt_metacast(char const *)" (?qt_metacast@ThreadsMiniature@@UEAAPEAXPEBD@Z)

threadsminiature.obj:-1: ошибка: LNK2001: unresolved external symbol "public: virtual int __cdecl ThreadsMiniature::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@ThreadsMiniature@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z)

threadsminiature.obj:-1: ошибка: LNK2019: unresolved external symbol "public: void __cdecl ThreadsMiniature::drowMiniature(class QImage)" (?drowMiniature@ThreadsMiniature@@QEAAXVQImage@@@Z) referenced in function "public: virtual void __cdecl ThreadsMiniature::run(void)" (?run@ThreadsMiniature@@UEAAXXZ)

debug\ObservationLog.exe:-1: ошибка: LNK1120: 4 unresolved externals

haifisch

@kshegunov All right. Many thanks.

SGaist

Hi,

You signal definition is wrong. See Qt's documentation about them. Basically, their return type is void and you don't implement them yourself.