CODEWITHSUNDEEP
c++qt
DragonautX
DragonautX

Reputation: 880

How do I access the QLineEdit widget I added to this Qt example?

I followed this Qt tutorial on signals and slots, including the part where you delete the connection you can automatically make in Qt Designer and instead type in the connect function by hand in mainwindow.cpp. I wanted to make my own slot where moving the tutorial's QSlider changed a QLineEdit I added, so I did this:

  1. I added a QLineEdit widget named lineEdit to my mainwindow.ui in Qt Designer.

  2. In the MainWindow class definition in mainwindow.h, I added this at the bottom of the class.

    public slots:
  void changeLineEdit() {
  ui->lineEdit->setText("Value was changed");
}

  3. In the MainWindow constructor in mainwindow.cpp, I added this: (ui->horizontalSlider was the QSlider made in the tutorial.)

    connect(ui->horizontalSlider, SIGNAL(valueChanged(int)), SLOT(changeLineEdit()));

When I tried to build the project, I got 9 errors, one of them being "use of undefined type Ui::MainWindow". What did I do wrong in this edit?
The MainWindow class definition has a private pointer Ui::Mainwindow *ui, so I thought the slot definition would access the ui pointer and therefore the lineEdit widget included there.

Upvotes: 1

Views: 837

Answers (1)

drescherjm
drescherjm

Reputation: 10827

If you implement your slot in your header make sure you include the header for UI::MainWindow in your header for your class as well. Normally I would implement my slots in the cpp file instead however that is not a requirement.

Upvotes: 1

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