Qt Several tableWidgets share linked Items
Hi, in Qt I have a QMainWindow -> centralWidget (QWidget) -> QtabWidget -> then 10 Tabs (QWidgets) -> each with up to 26 QtableWidgets:
Sample 1
Sample 2
The idea is that instead of this:
void MainWindow::on_pushButton_Add_Player_clicked()
{
ui->tableWidget_Players->insertRow(ui->tableWidget_Players->rowCount());
ui->tableWidget_Defensive->insertRow(ui->tableWidget_Defensive->rowCount());
.
. [10 tableWidgets in Total]
.
ui->tableWidgetAll->insertRow(ui->tableWidget_Players->rowCount());
}
Is there a way so that I can add a column each time to every tableWidget with less code.
Of course that's not there is to it, in fact I want to know is there is a way to link some of the Items of each that are actually the same Item but it's repeated in each like for example the Player Name is the same per row in each tableWidget, so if the user edits the name in one, it should change it in the same row in every tableWidget.
Is there a way to link them somehow, or the only way it's checking for item changes as signals.
I would also like that if I sort by column in one tableWidget, the new arrangement of the rows should be the same in every tableWidget.
Can anyone point me in the correct direction, the only idea I have it's using signals for ItemChanged. Isn't there a better way?
Thanks a lot for your time.
If your tables are the same data, you should consider getting some nice model view controller action going (also say that phrase a lot when applying for jobs, they like that ;))
To do this you need to create a tablemodel. And a TableView widget. This way, the data is shared, so it exists in only one place. All your TableViews just show the data. You can have a look at QSortedFilterProxy to filter your data for a specific view(i have never used this, so don't know). That way you have your playerModel somewhere, and each view has a proxyModel that only shows for instance the active players.
INTRODUCTON:
I am working on a drag and drop feature of the listview. I am stuck at the last step -> rearranging multiple selected items after user finishes drag and drop.
QUESTION:
Can you explain me the algorithm that implements item rearrangment?
I have the index of the clicked item after user releases the mouse. I have indexes of dragged items and their count. Pseudo code is acceptable as well, but be warned that I might have follow up questions.
NOTE:
This post has been edited in response to the comments that claimed my original question did not seek user friendly implementation.
The point is to implement standard drag & drop behavior, and the reason I phrased my question poorly at the first place was my lack of experience with this topic.
If further clarifications are required I will update my post.
Regards.
Normal drag & drop reordering removes the selected items and reinserts them in the new spot. It would be pretty unintuitive for the existing items in the new spot to jump to where the old ones came from.
To implement "standard" reordering, basically you:
Remember the index of the item below where the user drags your items to. In your example above, this would be 5 (assuming the new items are to be inserted above Item 6)
Remove the dragged items from the list one at a time using LVM_DELETEITEM
If the dragged items were originally above the new position, subtract the total number of dragged items from the index you remembered in step 1. This would give us 2 using the examples above.
Finally, reinsert the dragged items at the remembered index (remembering to increment the new index for each additional item). For example, the first dragged item would be inserted at position 2, then the next at 3 and so on.
Also note you need special handling for the case where the items are dragged to the top of the list. In that case, you would start the insertion at 0, then 1 and so on.
I have a QTableView with 80+ columns displayed in it. The subclass i have created for QTableView allows has functionality for the standard table stuff i wanted e.g order by columns move columns and rows hide column and rows etc.
However the problem i have is the view's focus. lets say you have all the data in the table, you scroll all the way to the right so you are looking at columns 70-80 (assuming 10 columns fit on the screen at once) if i click the header of row 80 (to order by column 80) the table reorders (as expected) however it also jumps the view to the last focused cell (which as far as i can tell is the cell that was last clicked)
What i want to do is not necessarily refocus on the column that was clicked because this might still change the view what im looking for is to just keep the view's focus exactly as it is instead of having it jump back to where the last clicked cell was?
Is there some flag im missing for focus policy or will i need to get the current view and set the view back to that view after mouse clicks that reorder the table and if so how could this be done.
Im aware i have provided no code for this question but it doesnt seem there is any needed since its not a bug im looking to fix more of a feature im unaware of, if you want to see any just comment
EDIT:
Im using a QSortFilterPorxyModel, this seems to get set once (when i call this->setSortingEnabled(true); after the initial call to this on contruction my table model never calls sort again. I have a slot linked to the header clicked signal, and i set the scroll bars to scrollTo() to the index clicked, but i think the sort is happening after this so it does nothing, any idea of what signal are emitted after sorting so i can catch them and then set the view back maybe?
thanks
Before you do your sort, store the current values for where the scroll bars are with
int vPos = yourQTableView->verticalScrollBar()->sliderPosition();
int hPos = yourQTableView->horizontalScrollBar()->sliderPosition();
then after the sort, set it back
yourQTableView->verticalScrollBar()->setSliderPosition(vPos);
yourQTableView->horizontalScrollBar()->setSliderPosition(hPos);
The signals you are looking for are signals of QSortFilterProxyModel inherited from QAbstractItemModel:
layoutAboutToBeChanged()
layoutChanged()
I couldn't reproduce your symptoms by creating a QTableWidget, filling it up with random stuff, and then sorting a particular column. The selected cell stays selected, but does not become visible if it has scrolled off screen.
So the question is, what is causing the behavior you're seeing. It sounds as though scrollTo() is being called by some other function. Since that's a virtual function, I would override it with a pass-through function and see when it's getting called.
I want to delete a selected row from the table when I click on the delete button.
But I can't find anything regarding deleting rows in the Qt documentation. Any ideas?
You can use the bool QAbstractItemModel::removeRow(int row, const QModelIndex & parent = QModelIndex()) functionality for this.
Here you can find an example for all this.
Also, here is an inline quote from that documentation:
removeRows()
Used to remove rows and the items of data they contain
from all types of model. Implementations must call beginRemoveRows()
before inserting new columns into any underlying data structures, and
call endRemoveRows() immediately afterwards.
The second part of the task would be to connect the button's clicked signal to the slot executing the removal for you.
If you are removing multiple rows you can run into some complications using the removeRow() call. This operates on the row index, so you need to remove rows from the bottom up to keep the row indices from shifting as you remove them. This is how I did it in PyQt, don't know C++ but I imagine it is quite similar:
rows = set()
for index in self.table.selectedIndexes():
rows.add(index.row())
for row in sorted(rows, reverse=True):
self.table.removeRow(row)
Works perfectly for me! However one thing to know, in my case this function gets called when a user clicks on a specific cell (which has a pushbutton with an 'X'). Unfortunately when they click on that pushbutton it deselects the row, which then prevents it from getting removed. To fix this I just captured the row of the sender and appended it to the "remove_list" at the very beginning, before the "for loops". That looks like this:
rows.add(self.table.indexAt(self.sender().pos()).row())
You can use another way by deleting the row from database, then clear the model and fill it again, this solution is also safe when you are removing multiple rows.
I have a list of items as a part of a web application. The question is how user can manipulate the order of items in the list (not the list sort order). The typical way is to use arrow buttons to move items up or down. The other way is the drag-and-drop.
But are there any other ways for a user interface for list reordering?
There are two other sorting methods (besides those you mentioned) I've seen which work pretty well.
Click To Move
The method used for ordering items in the Gallery web photo album works pretty well for ordering photos, and it should work just as well for any set that can be represented as a sorted group of clickable elements:
Present your list of items as clickable elements.
Clicking an element "selects" it, it is highlighted to indicate it's selected.
Clicking another item moves the selected item to a position just before the clicked item.
Repeat until all items are in the desired order.
A dummy item is shown at the end of the list for moving items to the end.
This is slightly easier to use than drag-n-drop as it requires less dexterity, and you don't have to hold down the mouse button while you figure out where you want to "drop" the item.
The method could easily be extended to allow selection of multiple items (via shift-click or similar) which could then be placed in a new position in the same way.
Provide Order Numbers
Used by Netflix and some internal apps I've worked with. This works best if your users have a concrete idea of exactly what the numeric order should be (used when working with lists of instruction steps in our internal app).
Present your list of items one per line.
Provide a text entry box next to each item where the order number is displayed, starting with 1.
The user changes the order numbers in the text fields as desired.
If multiple items are given the same order number, they are placed next to each other.
Provide a button to "apply" the sort in JavaScript so that the user doesn't have to submit the entire page to see the re-arranged list. This makes it easy to work in increments.
Edit: A couple of additional thoughts on Drag-and-Drop. You might have used these before or not, but there are a few things that can make drag-and-drop more forgiving and easier to use:
Highlight the area where the item will appear when dropped. For example, show a prominent horizontal line between the two existing items where the item will be inserted if it is dropped.
Ghost the draggable item as it is dragged so that it's obvious what's being moved, rather than using a generic "dragging" cursor. This works best if the items being dragged are still legible if shown on top of one another with transparency.
Make sure the target areas where the draggable can be dropped are sufficiently large. Larger areas can be helpful for people who have trouble with the required coordination.
We've found that drag and drop can be counter intuitive for non-technical people. We have explored the Up Down Arrow which works but can also be cumbersome as you need to keep clicking up and down and it results in a lot of traffic.
Another paradigm we've explored is the Move button so each item in a list has a Move Item button when you click it new buttons are added before and after each item in the list to let you move the item to any location.
This works well when each item in the list takes a lot of space, if each list item is only a single row it can result in a cluttered interface. In our case each item was half a dozen lines of text or more. We also have add item here button before / after each item to allow insertion.
Survey Monkey uses this paradigm as well and inspired some of what we do.
Some thoughts - Very much on the ideas rather than implementation end though...
1 - Provide both up and down arrows and drag and drop, and monitor which is more popular, which type of users use which etc, then tailor from there once you have some data
2 - Add a "random" button which generates the order randomly - could be useless, could be fun depending on your app
3 - Add a "display order" field by the side of each item and allow the user to manipulate it (but make sure that you have some code to auto update the rest of the numbers when one changes) personally I think this could be very confusing, but for some users it might work
4 - Instead of drag and drop in place, have users drag to a new list
5 - For a very simple version, have a "favourite" check box, and then have the list just show the favourites first, (in alphabetical order or something)
6 - Have groups - you assign a group number to an item, all the group ones appear first, followed by group 2 etc
Hope this random rambling has been useful, if i think of anything more I'll come back...
1) A variation of Click to Move would involve having a separate target list, where the user selects the slot into which their item will move, then clicks on the original item to move it.
For example, in the following diagram, the user has already put 'E' at the head of the reordered list and has selected slot three for their next choice. Their next step would be to choose which item from the old list goes into slot three on the new list. (The row of asterisks is a feeble attempt to show that slot three is highlighted or selected.)
old new
----- -----
| A | | E |
| D | | |
| C | |*****|
| | | |
| B | | |
----- -----
Clicking on an item in the new list selects it and highlights its original slot in the old list, which is now a target. Clicking on the item a second time returns it to that original slot.
The new list should also display indicators of some sort to show that it has selectable regions, perhaps unobtrusive (low-opacity) numbered buttons in its slots or some other informative affordance.
2) Another approach would be to allow users to draw lines between the original and desired positions.
Whatever method is chosen, the process need not be chatty: there's no reason this couldn't all be done client side (with the option to save and commit changes to the server).
You can experiment with drag-and-drop using the examples of jQuery UI Sortables.
To make it obvious for the non-technical or new users you could use visual cues such as handles or arrows and maybe a tooltip on hover to suggest dragging the element.
You could even provide an animated gif demonstrating the gesture.
As soon as a user learns how to do this I think it's the easiest method of ordering a list.
Another way is to provide a small text input next to every item, so the user can enter a numerical ordering themselves; then they click a button to reorder it all at once. (I've only seen this used on sites that store the order of items, such as Netflix queue or Livejournal links.)
Sorting, by clicking on headers is very popular. Perhaps only considered as a reordering of the view of the actual list, though.
Implement a copy/paste style function? This would mean you can take an item out of the list, and then select another item, and click "paste" or CTRL+V. This is quite intuitive and would allow large lists to be manipulated easily.
You could implement multi-selection easily to move a large block of adjacent items.
Network traffic would be low (only one or two requests).
You need to make sure the "paste" is consistent. I.e. pasting always inserts above the selected item.
Take a look at Checkvist for more inspiration.
You could also use arrow keys to move up and down.
I actually think the iphone / itouch does this really well when moving application icons.
If you haven't seen it look here: http://www.youtube.com/watch?v=qnXoGnUU6uI
The 'shaking' icons are a very good visual cue that something is moveable/draggable.
So I would suggest this approach with drag an drop. Clicking and holding on an item could put it in 'moveable-mode' and this would be indicated by it shaking (or some easier to code visual cue). Then drag and drop would work in the normal way.
Implementing this in javascript is of course the challenge...
Also another thing to think about - most people make the mistake of conflating usability with learnability. Think who the users of this app are (will they use it regularly and be taught how to use it, or are they public web users who may use it infrequently and not be taught how to use it) - it might give you a different answer to what the solution should be.
To me, performing a drag and drop of list elements in place (i.e. within the list itself) is the best approach.
Not only you can give to your users the immediate idea of what their list will look like (the list is reorganizing before their eyes), but it's also very easy for them to understand the moving mechanism.
And this is the briefest way to have your users ordering the list in the shortest number of moves.
By the way, foreseeing that a list could be longer than few elements, alongside the DnD method you could provide an asynchronous way to order the list: give the user the ability to attribute an ordering number to each entry, and then click on the "Order" button.
Handling in a smart and correct way user's input, this could result in a speed up for longer lists editing.
I was thinking of "Move selected to here":
Let all items be selectable by checkboxes
Let all items have a button or icon meaning "Move selected to here"
When "Move selected to here" is clicked, all selected items are moved to this item in existing order
The edge-cases here are when the items should be moved to either end of the list. One way to solve that, is to move all selected items before the target, and reserve a special button/icon at the end to move the selection there.
I've found the following to be the quickest way to allow specifying item order regardless of list size:
1) If user wants to set the order of list/grid items, they click a "Reorder" button.
2) This opens the reordering dialog which can be used with any list or grid.
3) In the dialog, all of the items are shown in their current order in a list on the left. There is an empty list on the right.
4) The user clicks the items in the left list in the desired order. When an item is clicked, it is removed from the left list and placed in the right list in the next position. In a worst case reordering where every item needs a new order, this allows ordering a list of N items with N clicks.
5) The user can then apply the new order or cancel. Applying the order results in the "display order" field in the data being set to the final order of the items in the right list. You can decide if the "Apply" button is only enabled when the left list is empty.
6) Also available in the ordering dialog are the following controls:
a) A button to move all of the items from the left list to the right list maintaining whatever order they are in
b) A button to start over by reloading the left list in its original order and clearing the right list.
c) A button to sort the right list alphabetically (or by date or numerically depending on what the key field is)
d) Drag and drop capability in the right list to manually drag items into order.
e) An index number column in the right list which, if edited, moves the item to that position.
This provides the best of all worlds. If you have a huge list where only a few items need to be moved, move all items over, then drag the few items where desired or enter the desired index. If you have a small-ish list that needs to be completely reordered, just click the items in the desired order. And so on.
I've used this approach for many years and it has been very effective.
You can show 'Up' and 'Delete' buttons just the way Google does for SearchWiki. Most of the people have at least some experience with it now. Most people bother only with 'Upping' their choice. If they do not like a thing, and want to downvote it, removing from the list with help of the abovementioned 'Delete' button will be easier for them
You could show an overlay when hovering over an element. This overlay shows you 4 arrows (n/e/s/w) and u can click and move the element accordingly.
If you are trying to oder items across a grid like facebook's and picasaweb's photo grouping features, then that is about the only way to handle that
if you had 3 columns each with a list of items, clicking on any of the items would move the item either to the left or right, middle column could show option for left or right. you could still allow for dragging and dropping or sorting using the typical functionality for that.