Vector of QLabels

[jss193]

Hello everybody,

I am trying to create a QVector of QLabels to add dinamically labels such as:

QVector <QLabel*> labels;

but it does not run because theoretically it says use of undeclared identifier QLabel.

so, if I try to append a QLabel such as labels.append(new QLabel);

It does not work, why?

thanks!

[Gerhard]

#include <QLabel>

[jss193]

I did it, but It does not work...

[mrjj]

@jss193
Hi
it must work or the #include is not in the same file where you have
QVector <QLabel*> labels;
or where you have
labels.append(new QLabel);
Also,
make sure you have
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
or
QT += widgets
in your .pro file.

[JonB]

@jss193
What "does not work"?

"use of undeclared identifier QLabel" sounds like a compile-time (or just possibly link-time) error, so I don't know what you have in mind by "it does not run"....

[jss193]

@mrjj Now it works, and it is creating QLabels dynamically, in my h file I have:

private:
    Ui::MainWindow *ui;
    QAbstractItemModel *model;
    int columns = 7;
    int rows = 0;
    QVector<QLabel*> labels;
    int countLabels = 0;
private slots:
    void changeText();
};

And in .cpp:

void MainWindow::on_pushButton_clicked()
{
    model->insertRows(0,1);

    QSpacerItem *item = new QSpacerItem(1,1,QSizePolicy::Expanding,QSizePolicy::Fixed);
    ui->horizontalLayout_2->addSpacerItem(item);

    for(int i =0;i<1;i++){
        labels.append(new QLabel);

        ui->scrollArea->setWidgetResizable(true);
      
        ui->horizontalLayout_2->insertWidget(i,labels[countLabels]);
        countLabels =countLabels +1;
    }

}

But it does not add labels to my layout, before I had the following code and it added Qlabels when pushing the button:

void MainWindow::on_pushButton_clicked()
{
    model->insertRows(0,1);

    QSpacerItem *item = new QSpacerItem(1,1,QSizePolicy::Expanding,QSizePolicy::Fixed);
    ui->horizontalLayout_2->addSpacerItem(item);

    for(int i =0;i<1;i++){

        QLabel *label1 = new QLabel("aaaa");

        ui->scrollArea->setWidgetResizable(true);
        ui->horizontalLayout_2->insertWidget(i,label1);
        
    }

}

Why now it is not creating the QLabels??

[jss193]

Fixed, it was creating empty QLabels I just added the text:

labels.append(new QLabel("TEST"));

[JonB]

@jss193

I did it, but It does not work...

Now it works,

Amazing how these things just happen!

[Pl45m4]

@JonB

@JonB said in Vector of QLabels:

Amazing how these things just happen!

Reminds me of:

• "My code doesnt work, and I dont know why" -> "My code works, and I dont know why"

:)