QTreeWidget & Drag Events

[Karl]

Dear All,

the default drag & drop behaviour of a QTreeWidget works fine.  But I did not manage to delegate the drag events to implement more specific features.

M->oTree:setDragEnabled( .t. )

M->oTree:connect( QEvent_DragEnter, {|p| execEvent( _dragEnterEvent__, p ) } )

M->oTree:connect( QEvent_DragMove , {|p| execEvent( _dragMoveEvent__ , p ) } )

M->oTree:connect( QEvent_Drop     , {|p| execEvent( _dropEvent__     , p ) } )

In my case the function execEvent() is never called?!

Please find a simple self contained example attached. It does work with other QWidgets e.g. QLineEdit or alike.  I also tried to connect to the model and/or to each QTreeWidgetItem.  No effect.  Yes I looked in hbIDE (e.g. in docks.prg) but I can't find the difference or what I am missing.

Thank you very much

 Karl

[Pritpal Bedi]

Hello Karl

the default drag & drop behaviour of a QTreeWidget works fine.  But I did not manage to delegate the drag events to implement more specific features.

M->oTree:setDragEnabled( .t. )

M->oTree:connect( QEvent_DragEnter, {|p| execEvent( _dragEnterEvent__, p ) } )

M->oTree:connect( QEvent_DragMove , {|p| execEvent( _dragMoveEvent__ , p ) } )

M->oTree:connect( QEvent_Drop     , {|p| execEvent( _dropEvent__     , p ) } )

In my case the function execEvent() is never called?!

Please look at hbide/projectwizard.prg.

This implements drag/drop of QTreeWidget to an extended level. 

QTreeWidget is implements drag/drop in different way than other widgets.

And let us know if you succeeded and in what way you implement 

in our application.

Pritpal Bedi

a student of software analysis & concepts

[Karl]

Dear Pritpal,

I also looked into projectWizard.prg.  What I don't understand is you enable the drag&drop in the QTreeWidget (:treeSrc):

      ::oUI:treeSrc:setDragEnabled( .t. )

      ::oUI:treeSrc:setDropIndicatorShown( .t. )

      ::oUI:treeSrc:setAcceptDrops( .t. )

Then you connect to the drag events in the parent QFrame (:frameSrc):

      ::oUI:frameSrc:setAcceptDrops( .t. )

      ::oUI:frameSrc:connect( QEvent_DragEnter, {|p| ::execEvent( __frameSrc_dragEnterEvent__, p ) } )

      ::oUI:frameSrc:connect( QEvent_DragMove , {|p| ::execEvent( __frameSrc_dragMoveEvent__ , p ) } )

      ::oUI:frameSrc:connect( QEvent_Drop     , {|p| ::execEvent( __frameSrc_dropEvent__     , p ) } )

This does not seem logical to me. But even if I try to use the same setup (adding a parent frame to my oTree) I do not get any events?!

 

And let us know if you succeeded and in what way you implement 

in our application.

Currently I am writing a tool to administrate my TODO items for internal use only.  Like this I learn hbqt which I plan on using to replace step by step the old GUI (gtwvt) of a harbour application of one of my customers.

Best regards

  Karl

 

[Pritpal Bedi]

Hi Karl

I also looked into projectWizard.prg.  What I don't understand is you enable the drag&drop in the QTreeWidget (:treeSrc):

      ::oUI:treeSrc:setDragEnabled( .t. )

      ::oUI:treeSrc:setDropIndicatorShown( .t. )

      ::oUI:treeSrc:setAcceptDrops( .t. )

Because QTreeWidget implements drag/drop in different wan than other QWidget(s).

Please read Qt documentation. The above code enables to accept drops and also enables

drag/drop from inside of QTreeWidgetItems. 

 

Then you connect to the drag events in the parent QFrame (:frameSrc):

      ::oUI:frameSrc:setAcceptDrops( .t. )

      ::oUI:frameSrc:connect( QEvent_DragEnter, {|p| ::execEvent( __frameSrc_dragEnterEvent__, p ) } )

      ::oUI:frameSrc:connect( QEvent_DragMove , {|p| ::execEvent( __frameSrc_dragMoveEvent__ , p ) } )

      ::oUI:frameSrc:connect( QEvent_Drop     , {|p| ::execEvent( __frameSrc_dropEvent__     , p ) } )

This does not seem logical to me. But even if I try to use the same setup (adding a parent frame to my oTree) I do not get any events?

Logical or Illogical depend upon the usage. This is perfectly logical in this context.

As told earlier, QTreeWidget does not accept drops from outside of QTreeWidget controls.

So I enabled the parent to accept the drops, which in turn populate the QTreeWidget.

For example, in above code, whenever user drags sources from explorer to this 

QTreeWidget, which are accpted by its parent frame, are parsed and populated to 

respective nodes, i.e., .prg under node "Prg Files", and so on.

Try to have a feel of it by playing with <Projects><New Project Wizard> opened dialog.

Do not open existing .hbp as this implementation is still work-in-progress.

Thanks for sharing your usage details.

Pritpal Bedi

PS: the drop events will be captured in the parent handellers. Parent has to be 

enabled for accepting the drops.