CODEWITHSUNDEEP
qtqwidgetqwebview
Geore Shg
Geore Shg

Reputation: 1329

QWebView - QWidget: must construct a QApplication before a QPaintDevice error

Whenever I try to create a new QWebView, the post-build error is

QWidget: Must construct a QApplication before a QPaintDevice

why is this happening?

Yes, i did add QT += webkit to the pro file, and it says here

In qwtconfig.pri

CONFIG += QwtDll this line must be ->

#CONFIG += QwtDll

where is qtwconfig.pri?

FWI i'm on a static build

Here is main()

#include "MyWidget.h"
#include <QPlastiqueStyle>
#include <QtPlugin>
#include <QtWebKit/QWebView>
Q_IMPORT_PLUGIN(qico)


int main(int argc, char *argv[])
{

QApplication app(argc, argv);

app.setStyle(new QPlastiqueStyle);
app.setFont(QFont("Calibri"));
MyWidget widget;
widget.show();

QWebView w;
    w.show();

return app.exec();

}

Upvotes: 1

Views: 2983

Answers (4)

darklon
darklon

Reputation: 478

Another source of this error can be linking to the wrong version of a Qt library - a release version for a debug build or vice versa.

Upvotes: 0

Silas Parker
Silas Parker

Reputation: 8147

The documentation mentions Webkit may not work as a static library.

From the Platform and Compiler Notes page:

WebKit is only supported as a dynamically built library. Static linkage is not supported.

Try dynamic linking instead.

Upvotes: 1

Silas Parker
Silas Parker

Reputation: 8147

Assuming you are creating a QApplication, make sure you're not statically allocating the object.

Don't do this

QWebView w;
int main(int argc, char *argv[])
{
  QApplication a(argc, argv);
  w.show();
  return a.exec();
}

Upvotes: 0

Arnold Spence
Arnold Spence

Reputation: 22272

You need to instantiate a QApplication object in order to use any widget based class and it must be created first, so your main() should look something like this..

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QWebView w;
    w.show();    
    return a.exec();
}

Upvotes: 0

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