My first own Qt app

[tomy]

@raven-worx
Thank you for your reply but I want to use the widgets in my code, and as I said, by clicking the button named Show , its value to be shown in lineEdit .
Show is in line show_sl = new QPushButton(tr("Show")); in employee.cpp .

I later develop the code and add some function to be able to set the salary.

[VRonin]

at the bottom of the constructor add
connect(show_sl,&QPushButton::clicked,[this]()->void{my_Salary->setText( QString::number(mySalary ));});

[tomy]

What are these??!!
I'm new in Qt and you write things like &QPushButton::clicked,[this]()->void .... I don't understand these, sorry.

I think I need a signal and a slot like this:
I added these to the employee.h

signals:
    void show_salary();
private slots:
    void show_salary_in_lineEdit();

And a connect and the definition of show_salary_in_lineEdit() to the employee.cpp this way

connect(show_sl, SIGNAL(show_salary()), lineEdit,
            SLOT(show_salary_in_lineEdit()));
.
.
.

void Employee::show_salary_in_lineEdit()
{
   lineEdit -> setText(QString::number(mySalary));
}

Now the code runs but clicking the Show button doesn't do anything!

[mrjj]

Hi
When you use SIGNAL and SLOT macros, you can check if connect works with
qDebug() << "conn:" << connect ( xxx );
should return true;

[VRonin]

@tomy said in My first own Qt app:

What are these??!!

That's the Qt5 connection syntax with a lambda

I think I need a signal and a slot

You just need a slot

connect(show_sl, SIGNAL(show_salary())

show_sl has no signal show_salary hence @mrjj remark warning you that the connect won't work

---

this is correct

void Employee::show_salary_in_lineEdit()
{
   lineEdit -> setText(QString::number(mySalary));
}

now the connect:

connect(
show_sl //who sends the signal
, &QPushButton::clicked // what signal do you want to react to (in this case when the button is clicked)
,this // who should catch the signal
,&Employee::show_salary_in_lineEdit //what slot should be called
);

[mlago]

Hi,
Your connect code not is correc, what you need is connect de Button signal clicked with your Show function,Something like that:

 connect(show_sl, SIGNAL(clicked(bool)), this, SLOT(show_salary_in_lineEdit()));

How to Use QPushButton

If you allow me a question, would not it be easier for you to use the graphic editor instead of creating the graphic objects by code?

EDIT: I am sorry, I was responding when the @VRonin had already done so.

[calebhalvy]

@mlago,
@VRonin is using the new Qt5 Signal/Slot connection syntax, as he linked to here.

[tomy]

@mlago said in My first own Qt app:

Hi,
Your connect code not is correc, what you need is connect de Button signal clicked with your Show function,Something like that:

 connect(show_sl, SIGNAL(clicked(bool)), this, SLOT(show_salary_in_lineEdit()));

How to Use QPushButton

Thank you. I changed the connect the way you showed and the code ran as expected. Thanks again.

If you allow me a question, would not it be easier for you to use the graphic editor instead of creating the graphic objects by code?

I'm learning Qt using a book and it walks me this way. I will be taught the Designer mode shortly. :)

EDIT: I am sorry, I was responding when the @VRonin had already done so.

[tomy]

@mrjj said in My first own Qt app:

Hi
When you use SIGNAL and SLOT macros, you can check if connect works with
qDebug() << "conn:" << connect ( xxx );
should return true;

Thanks. Although the code runs fine now, let me ask how to use that code for example in my code? (instructions)

[mrjj]

@tomy
Hi
You can use qDebug() for many nice things :)

1: #include <QDebug>

2: use it

qDebug() << "text" << variable << "more text" << some_other_variable ;

[tomy]

Thank you.