QObject::connect: No such slot MainWindow::getThing(ctx)

grepAns

I am trying to create a GUI that interfaces with a redis server to get key values and display them in the GUI. When I build and run the code, I get an error:
QObject::connect: No such slot MainWindow::getThing(ctx).

After looking at the stack overflow answers, I still don't understand why my GUI can't recognize the slot that I created.

Main.cpp

#include "mainwindow.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}

MainWindow.cpp

include "mainwindow.h"
#include "ui_mainwindow.h"
#include "hiredis/hiredis.h"
#include <string>
#include <iostream>
#include <QString>
#include <QTimer>
#include <QVector>
#include <QListWidget>
#include <QDateTime>
#include <QFileDialog>
#include <pthread.h>
#include <QtConcurrent>

QString getRedisValue(redisContext *ctx, QString cmdPrefix, QString keyName);
void getThing(redisContext *ctx);



MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    setWindowTitle(tr("Vorrina"));
    //Establish redis connection
    redisContext *ctx = redisConnect("127.0.0.1", 6379);
    if (ctx != NULL && ctx->err){
            printf("Error: %s\n", ctx->errstr);
            // handle error
    }
    //ui->label->setText("Hello");

    timer = new QTimer(this);
    connect(timer, SIGNAL(timeout()), this, SLOT(getThing(ctx)));
    timer->start(1000);

}

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

QString MainWindow::getRedisValue(redisContext *ctx, QString cmdPrefix, QString keyName){
    QString cmd= cmdPrefix + keyName;
    QByteArray cmdBytes = cmd.toLocal8Bit();
    redisReply *reply;
    void *pointer = NULL;
    pointer = redisCommand(ctx, cmdBytes.constData());
    reply = (redisReply*)pointer;
    QString keyValue = QString(reply->str);
    freeReplyObject(reply);
    return keyValue;
}


void MainWindow::getThing(redisContext *ctx){
    QString label = getRedisValue(ctx, "GET ", "answer");
    if(QString::compare(label, "ITS_HERE") == 0){
        ui->label->setText("ITS HERE");
        ui->label->setStyleSheet("QLabel { background-color : red; }");
    }
    else if(QString::compare(label, "NOT_HERE") == 0){
        ui->label->setText("NOT HERE");
        ui->label->setStyleSheet("QLabel { background-color : #90ee90; }");
    }
    else{
        ui->label->setText("LOOKING FOR IT");
        ui->label->setStyleSheet("QLabel { background-color : yellow; }");
    }
}

Mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <string.h>
#include <hiredis/hiredis.h>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();
    QString getRedisValue(redisContext *ctx, QString cmdPrefix, QString keyName);

public slots:
    void getThing(redisContext *ctx);

private:
    Ui::MainWindow *ui;
    QTimer *timer;

};
#endif // MAINWINDOW_H

SGaist

Hi,

You can't pass parameters values in your connect calls. Even more you can't do a connection from a signal with no parameters with a slot that has parameters unless they have all default values.