I have two QTreeViews side by side and I want to implement dragging one item from one table into the other table. What I would like to do however is that when the item to be dropped reaches the destination table, that the two rows sort of "make space for it" and separate to really show the user exactly where the item would be dropped. Could someone point me in the right direction as to how to do this as I have no idea really where to start.
Thanks,
Stephen
http://doc.trolltech.com/latest/dnd.html should lead you to pretty much anything you want to do re drag and drop.
As for your specific goal, you need to implement QWidget::dragMoveEvent(QDragMoveEvent* event), which will get called every time the mouse moves within the destination tree while dragging an item. Then get the position of the cursor with QDragMoveEvent::pos(). After that, while in dragMoveEvent, use QTreeView::indexAt(pos()) to get the item under the mouse. Now, I don't know how to get the items to separate in a smooth animated way, which would be ideal. But what you can do is (temporarily) add a blank item to the list, which will have the almost identical effect. Then implement QWidget::dropEvent() to handle the drop event, and when this happens delete the blank item and insert the dragged item in the location where it was.
Related
I use two different QGraphicView's and do drag'n'drop between them. The dragdrop does work very well so far. In one of my QGraphicView's I have items that receive hover events so that they are lighted when the mouse moves on them. The problem is that during drops and also during moves on items, the hover events won't get called. Is it possible to overcome this behaviour somehow? The hover events mark the places the drop can occur in my view and the items then have to be dropped at the right places accordingly (they can only be inserted at specific places and the user should get some feedback).
I hope I could describe my problem...I posted no code for now, because I do not know if this is even possible.
Thanks!
I'm not too familiar with the graphics view framework yet, but you'll probably need to subclass QGraphicsView (if you haven't already) and override QWidget::DragEnterEvent. Depending on how you coded your objects, they might also have a DragEnterEvent that you can use.
In either case you'd accept the QDragEnterEvent and have it trigger the hover event. Hope that points you in the right direction.
When I use treetable in Vaadin, it is working fine drag and drop the whole row when click the left and right blank ereas. but that is not user friendly, I wanna create a draggable layout inside the row, let's say the 1st component of the each row, that when clicking it, the whole row is selected and can be draged and dropped to reorder.
The thing is I can create a vertical layout with wrapper doing that, but drag mode is only for its component or the wrapper itself, and when doing the drag action, it doesn't actually showing the whole row is moving, which may confuse the clients. What can I do to make it looking like I am dragging the whole row, similar with the one you drag the blank area of each row? Thanks.
I'm afraid there currently is no way for adding a wrapper that would extend the entire row instead of just one cell. To do this you'd need to extend the client-side implementation of Table (VScrollTable) and this is not something I would recommend as it is quite complex.
I do think that what you describe should be possible in core Vaadin (without using drag & drop wrappers), so could you please file a ticket at dev.vaadin.com? And please attach a small application showing the problem to make it easier for us to see the problem and fix it.
Anyways, in order for you to get it working today I'd suggest that you change your UI design a bit and for example borrow drag handles from iOS. By this I mean that you could add an icon that suggests "draggable" as a background-image in the first cell (or in the row header cell of each row) that encourages the user to grab the row there, where it is "empty" and dragging works. This way the user might not be too confused if dragging only works reliably in some parts of the rows.
I'm having a QTableWidget with 10,000 records. I need to show only 30 rows at a time and hide the remaining rows. While dragining/clicking vertical scrollbar it should show corresponding rows and hide the other rows.
ie, if one clicks on upper scroll button it should show one more upper item and hide one lower item and vice versa. It should happen while scrolling as well.
Can anyone help me in doing this?
I think you can trap the events of up/down buttons as Nicholas said, for the tracking of slider/scroll bar u need use 'setTracking(true)'followed by the handling of signal either 'valueChanged(int)' or 'sliderMoved(int)'.
Thanks,
Pradeep
Qt unfortunately won't make this easy for you, there is ways and means of doing it however. Depending on how you're populating your widget I'd recommend setting it up so you initially populate your 30 rows, you then need to trap the signals coming from the scroll buttons being clicked and tell the table widget to remove the upper/lower item and add the next one, there's trade off's to this method, but it'll make it easier than trying to maintain a large list of hidden rows.
I don't know if explicitly showing/hiding things is the way you want to go. Instead, take a look at Qt's model and view classes. If you are using a database, have a look at QSqlTableModel, which should handle these things for you. Otherwise, have a look at the Model-View programming document, their related examples, and especially the portion about optimizing for performance (although in a model, 10,000 records isn't really all that many for most uses).
There is a way to change table scrolling from pixels to items. In Designer Property Editor for the table, in the QAbstractItemView section, there is a VerticalScrollMode selection. This can either be ScrollPerPixel or what you probably want, ScrollPerItem.
That may change the behavior of the signal from pixels to items which would make your calculations easier.
I'm using 4.4.3.
Hai,
I am trying to create a chess board. Here I want to do a operation like when ever a coin is clicked and dragged, at that time that picture should be copied and be placed in that old position. I don't know in which function I have to do it. When I made it on mouse pressed, then tyhe copy is coming above the original(layer wise). So somebody please help me
When I made it on mouse pressed, then tyhe copy is coming above the original(layer wise).
When you got this far, simply adding a call to myItemCopy->setZValue( -1 ) would place the copy "behind" the original item.
A different approach, and possibly "cleaner", would be to use QDrag and tell Qt how to paint your item during the Drag operation. See Qt's "Drag and Drop Robot" example for reference: http://doc.qt.io/qt-5/qtwidgets-graphicsview-dragdroprobot-example.html
Happy coding!
Robin
Simplest way to do this will be to put 2 identical QGraphicsItems for each coin/piece at the same location. The top one will be dragged and moved while the bottom one will stay for the visual cue you want.
Once the top one is dropped to the new location, move the bottom one there too.
I searched but couldn't find my answer, I'm sure it's easy for anyone with a little experience. I have multiple datagrids on a page, each one I want sortable with drag and drop, but I don't want items drug from one control to the other. How can I prevent a user from dragging an item out of a conrol. I would prefer to have it just stop moving with the mouse, but I am prepared to just completely cancel out of the dragging if need be.
I was trying to do something like this
dragExit="dragEvent.CANCEL"
This is obviously wrong, but I can't find the correct way to do it.
Thanks in advance.
~Mike
Ok, so you have an app with multiple drag/drop datagrids, and you only want items dragged within a datagrid, and not from 1 to the other, is how I understand this.
What you need to do is create a custom dragDrop event handler for each datagrid which has the following command: event.preventDefault(). This in effect will stop a datagrid from receiving items from another .
This does not prohibit the dragging an item outside its host's borders, but it will prohibit the item being dropped into a different datagrid.
HTH.