Signal and slot problem

SGaist

@jsulm you forgot to also make instancePtr static. However, I don't think the singleton pattern should be applied here.

jsulm

@SGaist Yes, I forgot, thanks for pointing :-)

azravian

@mrjj @SGaist
Now it's all working now but i cannot use ui memeber like label, lineEdit etc. For example

void MainWindow::inserted()
{
    qDebug()<<"Inserted...";
    ui->label->setText("Inserted");
}

i do get "Inserted..." but the label does not change Text :(

SGaist

Silly question but are you user the label is visible ? Do you have something on it before you call inserted ?

azravian

@SGaist yes for instance it has the default text "textLabel" and that's visible on GUI

SGaist

Then do you have something else that modifies that label ?

Things would be a bit easier if there was a possibility to see your code.

azravian

@SGaist
Sure Sir, it's the same code except i added just one line

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "gpio.h"
#include <QDebug>

bool firstTime=true;
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    if(firstTime)
    {
        gpio::Initialize();
        firstTime=false;
    }
    gpio* GPIO=new gpio;
    connect(GPIO,SIGNAL(RisingEdge()),this,SLOT(inserted()));
    connect(GPIO,SIGNAL(FallingEdge()),this,SLOT(Removed()));
    delete GPIO;
    ui->setupUi(this);
}

MainWindow::~MainWindow()
{
    delete ui;
}
void MainWindow::inserted()
{
    qDebug()<<"Inserted...";
    ui->label->setText("Inserted");
}

void MainWindow::Removed()
{
    ui->label->setText("Inserted");
    qDebug()<<"Removed...";
}

SGaist

If I may, you really should first cleanup your gpio class. It looks wrongly implemented and is wrongly used.

Make it a normal object i.e. don't use any static in it and don't make it a singleton. Once you have that sorted, it will be easier to integrate it in your GUI.

azravian

@SGaist
if i don't use ISR() and Initialize() as static i get error with wiringPiISR()
as
wiringPiISR (BUTTON, INT_EDGE_BOTH,&ISR);
it gives an error
error: cannot convert 'void (gpio::)()' to 'void ()()' for argument '3' to 'int wiringPiISR(int, int, void (*)())'
wiringPiISR (BUTTON, INT_EDGE_BOTH,&ISR);
^

SGaist

Ok, and there's no way to pass any parameter so here is an implementation example using a singleton:
WARNING : not tested on a Pi.

rpigpio.h

#ifndef RPIGPIO_H
#define RPIGPIO_H

#include <QObject>

class RpiGPIO : public QObject
{
    Q_OBJECT

public:
    static RpiGPIO *instance();
    static void destroy();

    static void initialize(int buttonNumber);

signals:
    void edgeRaised();
    void edgeFalled();

private:
    RpiGPIO();

    static void raisingEdgeCallback();
    static void fallingEdgeCallback();

    void onRaisingEdge();
    void onFallingEdge();

private:
    static RpiGPIO *_gpio;
};

#endif

rpigpio.cpp


#include "gpio.h"

RpiGPIO *RpiGPIO::_gpio = nullptr;

RpiGPIO::RpiGPIO()
   : QObject(nullptr)
{}

RpiGPIO *RpiGPIO::instance()
{
    if (!_gpio) {
        _gpio = new RpiGPIO;
    }

    return _gpio;
}

void RpiGPIO::destroy()
{
    delete _gpio;
}

void RpiGPIO::initialize(int buttonNumber)
{
    wiringPiISR(buttonNumber, INT_EDGE_RAISING, RpiGPIO::raisingEdgeCallback);
    wiringPiISR(buttonNumber, INT_EDGE_FALLING, RpiGPIO::fallingEdgeCallback);
}

void RpiGPIO::raisingEdgeCallback()
{
    RpiGPIO::instance()->onRaisingEdge();
}

void RpiGPIO::fallingEdgeCallback()
{
    RpiGPIO::instance()->onFallingEdge();
}

void RpiGPIO::onRaisingEdge()
{
    emit edgeRaised();
}

void RpiGPIO::onFallingEdge()
{
    emit edgeFalled();
}

Then you can do in your MainWindow:

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    RpiGPIO::initialize(numberOfTheButtonYouWantToMonitor);
    connect(RpiGPIO::instance(), &RpiGPIO::edgeRaised, [](){ qDebug("raising");});
    connect(RpiGPIO::instance(), &RpiGPIO::edgeFalled, [](){ qDebug("falling");});
}

MainWindow::~MainWindow()
{
    RpiGPIO::destroy();
}

If you want to be even cleaner, move the calls to initialize and destroy in your main.cpp:

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    RpiGPIO::initialize(buttonYouWantToMonitor);
    MainWindow mw;
    mw.show();
    int ret = app.exec();
    RpiGPIO::destroy();
    return ret;
}