How to create a button and place it where I want and then run a function when the button is clicked C++ QT

RuWex · 28 Sept 2022, 06:21

I'm new to qt c++:(
How to create a button and place it where I want and then run a function when the button is clicked?
I wrote this code but its not work...
///
QPushButton *m_button;
m_button = new QPushButton("My Button", this);
m_button->show();
m_button = new QPushButton("My Button", mainWind);
m_button->setGeometry(150, 150,150,150);
m_button->clicked();
///
can anyone help me??

jsulm · 28 Sept 2022, 10:18

@RuWex I answered this question in my first post in this thread: "You should use layouts to position widgets, see https://doc.qt.io/qt-6/layout.html"

jsulm · R RuWex 28 Sept 2022, 06:17

@RuWex said in How to create a button and place it where I want and then run a function when the button is clicked C++ QT:

qt c++

There is no such thing. Qt is simply a C++ framework.

Where did you write this code please? In constructor of your class.
You should use layouts to position widgets, see https://doc.qt.io/qt-6/layout.html
To trigger actions when a button is clicked use signals/slots: https://doc.qt.io/qt-6/signalsandslots.html

This makes no sense:

m_button->clicked();

clicked() is a signal and will be called by Qt as soon as user clickes then button. Connect a slot to this signal.

RuWex · 28 Sept 2022, 08:18

@jsulm
thank,
I wrote it in this function (if you know from application- example)

void MainWindow::open()
//! [7] //! [8]
{
    QPushButton *m_button;
    m_button = new QPushButton("My Button", this);
    m_button->show();
    m_button = new QPushButton("My Button", mainWind);
    m_button->setGeometry(150, 150,150,150);
    m_button->clicked();
    if (maybeSave()) {
        QString fileName = QFileDialog::getOpenFileName(this);
        if (!fileName.isEmpty())
            loadFile(fileName);

        QFile file(fileName);
         if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
             return;
        StartToSendCommand(fileName, textEdit);//Ruth
    }


}

jsulm · 28 Sept 2022, 08:40

@RuWex Please also read the rest of my previous reply...
I also don't understand why you're creating a button inside open(). What do you want to do with this button?

JonB · 28 Sept 2022, 08:50

@RuWex said in How to create a button and place it where I want and then run a function when the button is clicked C++ QT:

I wrote it in this function (if you know from application- example)

From what example? Please provide a link.
But also follow what @jsulm is asking/saying.

RuWex · 28 Sept 2022, 08:47

@jsulm I'm new in qt c++ and I dont so know, what can I do instaed of?
and i did it in open() because I want the button to appear when the option - open is choosen...

jsulm · 28 Sept 2022, 09:01

@RuWex said in How to create a button and place it where I want and then run a function when the button is clicked C++ QT:

what can I do instaed of?

First: explain CLEARLY what you want to do.
And please learn Qt basic stuff like signals/slots (read the links I posted).
"qt c++" - again, there is no such thing. Are you new to Qt, or also to C++?
If you need a button to pen a dialog then it should look like this:

MainWindow::MainWindow(...)
{
    m_button = new QPushButton("My Button", this);
    m_button->show();
    connect(m_button, &QPushButton::clicked, this, &MainWindow::open);
}

void MainWindow::open()
{
    if (maybeSave()) {
        QString fileName = QFileDialog::getOpenFileName(this);
        if (!fileName.isEmpty())
            loadFile(fileName);
    
        QFile file(fileName);
         if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
             return;
        StartToSendCommand(fileName, textEdit);//Ruth
}

RuWex · 28 Sept 2022, 08:59

@JonB
I took from the example that I got inside the software

JonB · R RuWex 28 Sept 2022, 08:50

@RuWex
If you cannot provide a link I can't look at it.

RuWex · 28 Sept 2022, 09:09

@jsulm said in How to create a button and place it where I want and then run a function when the button is clicked C++ QT:
thank you!!

I'll explain a little what I meant, I want to have the option of opening a file, and after opening the file a "start testing" button will appear, clicking on it will activate the function StartToSendCommand() which receives QString fileName, QPlainTextEdit *textEdit - which is a problem according to the option you gave me, it doesn't give in the function connect() to send parameters. Then I want the function to run on the file I opened... Is my question more understandable?

jsulm · R RuWex 28 Sept 2022, 09:01

@RuWex said in How to create a button and place it where I want and then run a function when the button is clicked C++ QT:

connect()

Connect is a method in QObject - all subclasses including QPlainTextEdit have it.
Modified version according your description (I don't understand why you're opening file without doing anything with its content, I also don't know what this textEdit is about and why it needs to be parameter, your code is really strange - I suggest you start from scratch step by step):

void MainWindow::open()
{
    if (maybeSave()) {
        QString fileName = QFileDialog::getOpenFileName(this);

        QPushButton *button = new QPushButton("Start", this);
        connect(button, &QPushButton::clicked, this, [=]() { sendCommand(fileName, textEdit); });
}

void MainWindow::sendCommand(QString fileName, QTextEdit textEdit)
{
    if (!fileName.isEmpty())
        loadFile(fileName);
        
    QFile file(fileName);
     if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
         return;
     StartToSendCommand(fileName, textEdit);//Ruth
}

RuWex · 28 Sept 2022, 10:00

I open a file and use its contents!
Basically, I open a txt file which is a file consisting of commands and I want that after the file is selected, it will be possible to click on "start testing" - then it will start running line by line from the file and the commands will be sent, so I actually need this whole process.
After what I've explained here, is the code understandable, or does it still not look professional (I'd appreciate comments, I'm new...)

and- @jsulm- I dont have link its in my software

RuWex · wrote on 28 Sept 2022, 09:27

wow it works!!!
Thank you!
I would appreciate an answer to my second question :)

jsulm · 28 Sept 2022, 10:06

@RuWex said in How to create a button and place it where I want and then run a function when the button is clicked C++ QT:

I open a file and use its contents!

Well, not here:

void MainWindow::open()
{
    QPushButton *m_button;
    m_button = new QPushButton("My Button", this);
    m_button->show();
    m_button = new QPushButton("My Button", mainWind);
    m_button->setGeometry(150, 150,150,150);
    m_button->clicked();
    if (maybeSave()) {
        QString fileName = QFileDialog::getOpenFileName(this);
        if (!fileName.isEmpty())
            loadFile(fileName);

        QFile file(fileName);
         if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) // You open the file here but DO NOT USE IT
             return;
        StartToSendCommand(fileName, textEdit);//Ruth
    }

What second question do you mean?

RuWex · 28 Sept 2022, 10:09

@jsulm

I have this code:

QPushButton *m_button= new QPushButton ("Start Testing", this) ;
QGridLayout *layout = new QGridLayout(this);
layout->addWidget(m_button,150,150, 100,140);
m_button->show();

how can I place the button, for example in the middle of the window? I use it:

QGridLayout *layout = new QGridLayout(this);
layout->addWidget(m_button,150,150, 100,140);
but its not help... and do nothing can anyone help me?

thanks!!!

jsulm · 28 Sept 2022, 10:18

@RuWex I answered this question in my first post in this thread: "You should use layouts to position widgets, see https://doc.qt.io/qt-6/layout.html"

RuWex · J jsulm 28 Sept 2022, 10:09

@jsulm ou! thank you!
you had helped me a lot!!