[SOLVED][Drag'n Drop] QMainWindow and linking error

Max13

Hi everybody !

I'm new to Qt, and I'm a little, very little confused with the Qt-Classes tree.

I wrote an app, which will crypt (with QCA) the dragged desktop files, dropped in my app (opened).
The thing is my main "window" is a QMainWindow inherited by my custom class.

I know that CustomClass -> QMainWindow -> QWidget, so the drag'n drop features should work directely on my class, isn't it? (according to: "F.A.Q":http://developer.qt.nokia.com/faq/answer/how_can_i_do_drag_and_drop_in_a_widget)

But, when I add the protected definitions in my class Custom {}, it fails compilling:
@Undefined symbols:
"MainWindow::dragMoveEvent(QDragMoveEvent*)", referenced from:
vtable for MainWindowin moc_mainwindow.o
"MainWindow::dragEnterEvent(QDragEnterEvent*)", referenced from:
vtable for MainWindowin moc_mainwindow.o
"MainWindow::makeDrag()", referenced from:
MainWindow::qt_metacall(QMetaObject::Call, int, void**)in moc_mainwindow.o
"MainWindow::dropEvent(QDropEvent*)", referenced from:
vtable for MainWindowin moc_mainwindow.o
ld: symbol(s) not found@

Any Idea :/ ?
And... At least, is it supposed to work T_T ?

PS: Here is my .h: http://pastebin.com/MgMH2GKX

Thanks for you help.

giesbert

Hi Max13,

can you please also show your cpp file?
I think you perhaps have forgotten the implementation?

Max13

Hi,
I've let the implementation away, I was testing.
Because I've noticed that GCC can complain about missing definition, but not for missing implementation.

Isn't it? =P

giesbert

You must at least have empty functions.
They needn't be filled but the function body is a must.

Max13

Ok, I'll do it.
BTW, do you know if the implementation explained in the FAQ, if I Want to be able to drag-n-drop from the desktop to my app? (since it's not a part of my app =/ )

?
Thanks for tour help!

giesbert

Hi,

I did that once and could dig a bit for it, but that takes time.
In general, you have to do it like in the docs, I never used this faq, only the online docs.

You can start at the "examples for drag'n'drop":http://doc.qt.nokia.com/4.7/examples-draganddrop.html

giesbert

Hi,

I created a small wiki article on how to open files from drag operations inside a QMainWindow:

"wiki article":http://developer.qt.nokia.com/wiki/Drag_and_Drop_of_files

On windows, I would connect that with the "assignment of file types":http://developer.qt.nokia.com/wiki/Assigning_a_file_type_to_an_Application_on_Windows

Hope that helps a bit.

Have fun.

Max13

Hi,

Thank you a lot !
I've added empty functions, and it worked (:/).

Thank, I saw your Wiki, GREAT !
But something wrong (perhaps from me, perhaps from Qt)

@void MainWindow::dropEvent(QDropEvent *de)
{
const QMimeData * mimeData = de->mimeData();

if (mimeData->hasUrls())
{
qDebug() << mimeData->urls(); // Line 10
}
}@

I have tons of errors :/
Line 10 above is line 10 here: http://pastebin.com/89k8G0aq

Thank you for your help anyway :)

giesbert

Hi Max,

I'm not sure, whether QList<QUrls> is able to be streamed to qDebug.
If you read the wiki, you will find I use the local paths of the urls, so like this:

@
void DocumentWindow::dropEvent(QDropEvent* event)
{
const QMimeData* mimeData = event->mimeData();

// check for our needed mime type, here a file or a list of files
if (mimeData->hasUrls())
{
    QList<QUrl> urlList = mimeData->urls();

    // extract the local paths of the files
    for (int i = 0; i < urlList.size() && i < 32; ++i)
    {
        qDebug() << urlList.at(i).toLocalFile&#40;&#41;;
    }
}

}
@

Max13

Sorry...

Usually, i'm less dumb ^^

I have the same errors with this line: @QList<QUrl> urlList = mimeData->urls();@

So:
@void MainWindow::dropEvent(QDropEvent *de)
{
const QMimeData * mimeData = de->mimeData();

if (mimeData->hasUrls())
{
QList<QUrl> urlList = mimeData->urls();
}
}@

Is the error between my chair and my computer ? =P

giesbert

[quote author="Max13" date="1302617263"]Is the error between my chair and my computer ? =P[/quote]

Perhaps :-)

I saw you are using Qt 4.7.3?
I only tried with 4.7.2... on windows
There I had no problems.

Are you missing some includes? The error talks about forward declarations...

@
#include <QtCore/QUrl>
#include <QtCore/QList>

@

Max13

Hi !
Sorry for having made the dead.

I've reinstalled the libs, did everything you explained, and...

IT WORKS GREAT !!

Thank you a lot for you patience.
I'm done now :)