Qt PushButton exec widgets

Question

I have a checkable pushbutton set to exec/close a dialog widget that I have created.

My idea is when the pushbutton is checked, it will close the dialog widget. If it's not checked, it should open the dialog widget. But I am unable to get it to work. It keeps on opening instances of the dialog widget. I wanted to open one instance of the dialog widget only. Could anyone please help?

MainDlg::MainDlg()
{
    connect(dialogButton, SIGNAL(clicked()), this, SLOT(setDialog()));
}

void MainDlg::setDialog()
{
   SetDialogDlg setDlg;
   if(dialogButton->isChecked())
   {
      setDlg.close();
   }
   else
   {
      setDlg.exec();
   }
}

Answer 1

There are a few things that are wrong in your code. First thing is, your SetDialogDlg object will only exist inside your MainDlg::setDialog() function. Once this function finishes your SetDialogDlg object will be destroyed.

Then you are creating a new instance of SetDialogDlg every time MainDlg::setDialog() function is called. And you are trying to close a dialog that hasn't been shown yet.

Then there is a problem with setDlg.exec(). This is a blocking function. So you shouldn't even be able to push your dialogButton once the dialog has been shown.

To solve these problems you should have a member variable in your MainDlg class.

//maindlg.h
...
public:
   SetDialogDlg *myDialog;
...

 

//maindlg.cpp
MainDlg::MainDlg()
{
   ...
   myDialog = new SetDialogDlg(this);
   ...
}

  Then inside your MainDlg::setDialog() function, call QWidget::show() instead of QDialog::exec().

void MainDlg::setDialog()
{
   if(dialogButton->isChecked())
   {
      myDialog->close();
   }
   else
   {
      myDialog->show();
   }
}