[solved]How to add a widget to window, when it is generated by method

Lord of Noob

Hi there,

I want in my app to generate some default Wifdget arrangements by a method.
For example:

//adds a label and a QTextEdit field to my window.
createItem(Name, InputType::Text);

My problem is that this is not working. If I try to return the objects from the Method, I run into an error which I do not understand as noob.

/usr/include/qt/QtWidgets/qlabel.h:142: Fehler: 'QLabel::QLabel(const QLabel&)' is private Q_DISABLE_COPY(QLabel)

If I define the naked pointers in the class as private variables the application Crashes.
Mainwindow.h

class MainWindow : public QMainWindow
{
   Q_OBJECT

public:
   MainWindow(QWidget *parent, std::string appname);
   ~MainWindow();
   void createCharItem(QString name, QString txtContent);
 private:
  //variables
  QVBoxLayout *section; //Stacks all items below each other
  QLabel *title;  // one Item to add
  //functions
  void createTitle(QString name);

}

implementation of void createTitle(QString name);

void MainWindow::createTitle(QString name)
{
     QLabel *title = new QLabel;
     title->setText(name);
     title->setLineWidth(40);
     int height = title->height();
     title->resize(this->width(),height);
     section->addWidget(title);
}

What do I miss?
Or how to do this?

mcosta

Hi and welcome to devnet,

can you show the implementation of createCharItem()?
QObject (or inherited classes) instances cannot be created on the stack (you have to use pointers)

Lord of Noob

@mcosta
Thanks the Welcome,

Ohh, I am sorry i was tired. The

 createTitle();

is a reduced version of

 createItem();

I do not have the createItem yet. It will look similar only it will consinst of a 1xQHBoxLayout,1xQLabel and 1xQTestEdit or 1xQSpinBox.

My Constructer of QMainWindow looks like:

MainWindow::MainWindow(QWidget *parent,std::string appname) :QMainWindow(parent)
{
   QTabWidget *charsheet = new QTabWidget;
   this->setCentralWidget(charsheet);
   QWidget *titlepage = new QWidget(this);
   QWidget *combatpage = new QWidget;
   charsheet->addTab(titlepage,"Heerosheeet");
   charsheet->addTab(combatpage,"combatsheet");
   QVBoxLayout *section = new QVBoxLayout(titlepage);
   createTitle(QString::fromStdString(appname));
/* If I do it this way it works ...
    QLabel *title = new QLabel;
    title->setText(QString::fromStdString(appname));
    title->setLineWidth(40);
    int height = title->height();
    title->resize(this->width(),height);
   section->addWidget(title);
   */
}

Ohh I just have seen if I move the

 section->addWidget(title);

to main, it works. But why I can not use the add Widget Method in my own method?

Edit:

Ok, fixed one Bug: QLabel was wrong. But the program is still crashing this way.

void MainWindow::createTitle(QString name)
{
     title = new QLabel;
     title->setText(name);
     title->setLineWidth(40);
     int height = title->height();
     title->resize(this->width(),height);
     section->addWidget(title);
}

Lord of Noob

Okay, I now found 2 Exceptions:
QXcbWindow: Unhandled client message: "_E_COMP_FLUSH"
QXcbWindow: Unhandled client message: "_E_COMP_DUMP"

I think I can catch them, but I do not know what to do with these Errors...

Google is not makeing any sense.
Marking the Handler and press F1 is not doing something :-D

Any hints where to look?

alex_malyu

My problem is that this is not working. If I try to return the objects from the Method, I run into an error which I do not understand as noob.
/usr/include/qt/QtWidgets/qlabel.h:142: Fehler: 'QLabel::QLabel(const QLabel&)' is private Q_DISABLE_COPY(QLabel)

There is an attempt to copy QObject derived object, probably cause you return object not the pointer.

If You need to create object of QWidget (QObject) derived class in a function, function should look like:

QWidget* createWidget();

not a
QWidget createWidget (), cause in such case object will have to be copied and it is forbidden.

Lord of Noob

Cool, this works.
I return now a Pointer, and add it in one line to the screen.

I mark this solved. Even I still have no Idea why the one way does not work.

great thanks.

SGaist

Hi,

Because QObject is not a copyable class. See here for more information