ui detect mouse event on objects

[Pfanne]

[WIN10] [MVS2019] [QtV6.3.1]

Hi,

in my code I got a lot of checkboxes.

    QCheckBox *IO_1;
    QCheckBox *IO_2;
    QCheckBox *IO_3;
    ... 
    ...
    QCheckBox *IO_46;
    QCheckBox *IO_47;
    QCheckBox *IO_48;

To check them by code I use a simple loop and select the checkboxes by searching for the object pointer by object name.

        for (int i = 0; i < 48; i++) {
            QString cbName = "IO_";
            cbName.append(QString::number(i + 1));
            QCheckBox* cb = ui->SITIPEMaster->findChild<QCheckBox*>(cbName);

            cb->setChecked(sitipe_master.ptm.id[id].io[i].value);
        }

instead of setting each cb separately...

        ui->IO_1->setChecked(sitipe_master.ptm.id[id].io[0].value);
        ui->IO_2->setChecked(sitipe_master.ptm.id[id].io[1].value);
        ui->IO_3->setChecked(sitipe_master.ptm.id[id].io[2].value);
        ui->IO_4->setChecked(sitipe_master.ptm.id[id].io[3].value);
        ui->IO_5->setChecked(sitipe_master.ptm.id[id].io[4].value);
        ...
        ...

that works fine....

now I want to detect a a cklick event on one of these checkboxes in a easy way.
I don´t want to check them alle in a own function/event...

    void on_IO_1_clicked();
    void on_IO_2_clicked();
    void on_IO_3_clicked();
    void on_IO_4_clicked();
    void on_IO_5_clicked();
    ...
    ...

I tryed it with :

protected:
    void mousePressEvent(QMouseEvent* event);

--------------

void MainWindow::mousePressEvent(QMouseEvent* event) {
    QWidget* const widget = childAt(event->pos());
    qDebug() << "child widget" << widget;
}

I got the following error:

"childAt(event->pos());"
ebent, type of pointer not alowed...

What is the correct way to detect mouse event on objects?

[medyakovvit]

@Pfanne

for (int i = 0; i < 48; i++) 
{
    QString cbName = "IO_";
    cbName.append(QString::number(i + 1));
     QCheckBox* cb = ui->SITIPEMaster->findChild<QCheckBox*>(cbName);

    cb->setChecked(sitipe_master.ptm.id[id].io[i].value);
    // you can use toggled() or clicked()
    connect(cb, &QCheckBox::toggled, cb, [id, i](bool checked)) {
        // here you have 'i' 
    });
}

[mpergand]

@Pfanne
You may have a look at QButtonGroup or QGroupBox

[Pfanne]

@medyakovvit

 // you can use toggled() or clicked()
    connect(cb, &QCheckBox::toggled, cb, [id, i](bool checked)) {
        // here you have 'i' 

what exactly happend here?
you connect the checkbox toggled/clicked event to ???
Where can I catch this event for further use?

[mpergand]

@Pfanne said in ui detect mouse event on objects:

what exactly happend here?

It is a lambda expression, see HERE

[JonB]

@Pfanne
It's a C++ lambda, like an "anonymous function". Search for lambda on https://wiki.qt.io/New_Signal_Slot_Syntax. @mpergand uses it here to pass the i value from the for loop for you to use in the lambda code, which identifies which checkbox has been toggled.

[Pfanne]

@mpergand

I take a look at QButtonGroup, this look like the right object for my usecase.
I tryed this:

*.h

private slots:
    void on_ioGroup_clicked(int id);

MainWindow::MainWindow(QWidget* parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)

{
    ui->setupUi(this);
    QButtonGroup* ioGroup = new QButtonGroup(this);
    ioGroup->addButton(ui->IO_1, 1;
    ioGroup->addButton(ui->IO_2, 2);
    
    connect(ioGroup, SIGNAL(buttonClicked(int)), this, SLOT(on_ioGroup_clicked(int)));
}

----

void MainWindow::on_ioGroup_clicked(int id) {
    qDebug() << "id clicked" << id;
}
    ```

but "on_ioGroup-clicked" will not be executed by clicking on  IO_1 or IO_2.

[JonB]

@Pfanne
Use the "modern" syntax for yourconnect()s and you would see there is no buttonClicked(int) with int parameter signal. OTOH there is a QButtonGroup::idClicked(int id) signal.

[Pfanne]

@JonB

yes, I also saw that "buttonClicked(int)" is not up to date!

this worked:

connect(ioGroup, &QButtonGroup::idClicked, this, MainWindow::on_ioGroup_clicked);

this not:

    connect(ioGroup, &QButtonGroup::idClicked(int id), this, MainWindow::on_ioGroup_clicked(int id));

[Pfanne]

@Pfanne

finaly this worked:

    connect(ioGroup, SIGNAL(idClicked(int)), this, SLOT(on_ioGroup_clicked(int)));

void MainWindow::on_ioGroup_clicked(int id) {
    qDebug() << "id clicked" << id;
    QAbstractButton* cb = ioGroup->button(id);
    qDebug() << "Object" << cb->objectName();
}

[JonB]

@Pfanne said in ui detect mouse event on objects:

this worked:
connect(ioGroup, &QButtonGroup::idClicked, this, MainWindow::on_ioGroup_clicked);

Correct.

finaly this worked:
connect(ioGroup, SIGNAL(idClicked(int)), this, SLOT(on_ioGroup_clicked(int)));

Since you had it correct first why change it?

[mpergand]

@Pfanne said in ui detect mouse event on objects:

connect(ioGroup, &QButtonGroup::idClicked, this, MainWindow::on_ioGroup_clicked);

You must specify an adress (&) here:
&MainWindow::on_ioGroup_clicked);

[JonB]

@mpergand said in ui detect mouse event on objects:

&MainWindow::on_ioGroup_clicked);

OIC I missed that when OP said it was correct.

[mpergand]

Hi @JonB

Off topic question :
How to set text color as you do in red in your posts ?

[Pl45m4]

@mpergand said in ui detect mouse event on objects:

How to set text color as you do in red in your posts ?

` Text ` = Text

[JonB]

@mpergand said in ui detect mouse event on objects:

How to set text color as you do in red in your posts ?

Interesting. I don't know and have never set a text color in any of my posts! :) @Pl45m4 post above with red text for Text is the first time I have seen any color.

Oh, hang on! Like buttonClicked()? LMAO, until today's forum update that was in green, no wonder I didn't know about red! The "color" is just up to the forum style. The important thing is that code is in monospace font. Use the Code icon (</>) when you are typing in. Or

`in-line codecharacters`

```

multiline code
multiline code

```
First one is single-backtick inline, second one is triple-backtick above and below block.

[Pl45m4]

@JonB said in ui detect mouse event on objects:

Interesting. I don't know and have never set a text color in any of my posts! :) @Pl45m4 post above with red text for Text is the first time I have seen any color.

I use this text format every time I mention some Qt term or class. QPushButton, QObject, Q_OBJECT.
So did/do you ;-)
I don't know what exactly you did when writing these posts, but I used single backticks (don't know how they are called)
` QPushButton ` (now escaped to make them visible)

LMAO, until today's forum update that was in green, no wonder I didn't know about red

I could swear it was red before, with some kind of red-ish background.
At least when used outside of a code section in regular paragraphs.

[JonB]

@Pl45m4 Maybe. Whatever I thought the original question was how to write in red, rather than in monospace which happens to show as red!

[mpergand]

@Pl45m4
Thanks for the tip :)

I finally found the Help button I was looking for yesterday that describes the markdown syntax.

[Pfanne]

@JonB
the first version:

connect(ioGroup, &QButtonGroup::idClicked, this, MainWindow::on_ioGroup_clicked);

is without the object ID, implementing the ID in this version a error occurse.