Signal and slot problem

azravian

i am trying to connect my signals and slots but it's not working codes are below

void gpio::ISR()
{
    gpio GPIO;
    if(gpio::isHIGH())
    {
        qDebug()<<"RISING Interrupt called";
        GPIO.emit_RisingSignal();
    }

    else if(gpio::isLOW())
    {

        qDebug() <<"FALLING edge";
        GPIO.emit_FallingSignal();
    }
}

void gpio::emit_RisingSignal()
{
    qDebug()<<"In Rising Function.";
    emit RisingEdge();
}

void gpio::emit_FallingSignal()
{
    qDebug()<<"In Falling Function";
    emit FallingEdge();
}

and in Header file

#include <QObject>
class gpio : public QObject
{
    Q_OBJECT
public:
    gpio();
    void static Initialize();
    void static ISR();
    bool static isHIGH();
    bool static isLOW();
    void emit_RisingSignal();
    void emit_FallingSignal();
private:

    static const int POWER=21;
    static const int BUTTON=20;
signals:
    void RisingEdge(void);
    void FallingEdge(void);

};

And in MainWindow.cpp

gpio* GPIO=new gpio();
connect(GPIO,SIGNAL(RisingEdge()),this,SLOT(inserted()));
connect(GPIO,SIGNAL(FallingEdge()),this,SLOT(Removed()));

void MainWindow::inserted()
{
    qDebug()<<"Inserted...";
}

void MainWindow::Removed()
{
    qDebug()<<"Removed...";
}

and in MainWindow.h

public slots:
void inserted();
void Removed();

When i Run this program i Get
RISING Interrupt called
In Rising Function.
FALLING edge
In Falling Function

but it should be
RISING Interrupt called
In Rising Function.
Inserted....
FALLING edge
In Falling Function
Removed...

So clearly the slots are not being called i can't figure out the problem and Help is badly needed.

mrjj

@azravian said:
hi
first thing to do is to use

qDebug() <<"con1" << connect(xxx

for all your connect and check they all return true;

azravian

@mrjj

qDebug()<<"Connection Rising edge: "<<connect(GPIO,SIGNAL(RisingEdge()),this,SLOT(inserted()));
    qDebug()<<"Connection falling edge:"<<connect(GPIO,SIGNAL(FallingEdge()),this,SLOT(Removed()));

gives the output

Connection Rising edge: true
Connection falling edge: true

mrjj

@azravian said:
ok super so they accept the connect.

your error is here

void gpio::ISR()
{
gpio GPIO; <<<<<<<<<<<<<< that is not the one u connect !?

That is not the
gpio* GPIO=new gpio();
one :)

Update:
So when you do
GPIO.emit_FallingSignal();
with your local copy, no signal is sent to mainwin as
its an other instance than the one you new in main.

azravian

@mrjj that's seems to be a problem but if i change my ISR()

void gpio::ISR()
{
    gpio* GPIO=new gpio;
    if(gpio::isHIGH())
    {
        qDebug()<<"RISING Interrupt called";
        GPIO->emit_RisingSignal();
    }

    else if(gpio::isLOW())
    {

        qDebug() <<"FALLING edge";
        GPIO->emit_FallingSignal();
    }
}
i have the same problem, it didn't solve the problem/

mrjj

but why are u creating a new Object???
Use the one in/from main.

That is the one you have connect to mains slots so making a new one
in that function will not send any signals to main as you do not connect it
like the other one.

So just newing the local copy instead, will not make any difference :)

mrjj

@mrjj

wait, i just saw
you create a gpio INSIDE gpio ????

why?

mrjj

I would expect

void gpio::ISR()
{

if(gpio::isHIGH())
{
    qDebug()<<"RISING Interrupt called";
    emit_RisingSignal();
}

No local object of same type! ?

azravian

@mrjj Sir, ISR() is a static function. So to access other functions of the class i need to create an object :) thats why i have defined two other function emit_RisingEdge() and emit_FallingEdge() so i can emit my signals independent of any object.

mrjj

Ok, if u create a instance for use with signals, then its fine.
You just need to connect this new object to the slots again.

azravian

@mrjj thanks but i'm pretty much beginner with signals and slots,where do i need to change my code

mrjj

@azravian
Hi,
void gpio::ISR()
{
gpio* GPIO=new gpio;
// here u need to connect again
// since its not pr type, but pr instance
// so the connect u made in main, are not on GPIO here

azravian

@mrjj thank you it worked thank you so much Sir :)

mrjj

@azravian
Super, np :)
sorry I missed ur static function. The scroll area is so tiny .)

azravian

@mrjj
Oh it's Ok sir, thanks Again for your input and help :) I've surely learned a lot

SGaist

Hi,

Just one thing, you have now a memory leak.

But in any case, I must say I don't see any reason for making all these methods static.

mrjj

@SGaist
Thank champ. In the static heat, i completely missed that.

@azravian
You should have a
delete GPIO in the end of the function or even better
just go back to using the stack again. (so it cleans it self)
void gpio::ISR()
{
gpio GPIO;

azravian

@mrjj @SGaist
Yes i noticed it later and have deleted it. thanks again sir

azravian

@SGaist thank you for it :) and the point od making these methods statics is that i am using wiringPi library which need a function as a parameter so i need make it static.

jsulm

@azravian In this case you could add a public static method to get the pointer to the gpio instance (basically you create a singleton):

class gpio : public QObject
{
    Q_OBJECT
public:
    gpio(): instancePtr(nullptr) {}
    static gpio* instance()
    {
        if (!instancePtr) instancePtr = new gpio();
        return instancePtr;
    }
private:
    gpio* instancePtr;

You can use this method in main to setup the connection and in static methods in gpio to get the pointer to the instance. Don't forget to delete the instance later.