We would like to do a TableView that allows complex content in its cells.
The TableView should be as generic that I can do simple stuff like in picture 1. The left image is a simple example, where I fill a simple TableModel, set it for the TableView and display it.
But what if I want to add more complex content to one cell? Please again look at the first picture. The right part is more complex, for every cell we want to display an image, a description, and more description, so three items in one cell.
I understand, that I can put widgets to the cells of a TableView.
But, if I want to have a proper TableModel in the background, how would I store the data?
On top, the view should automatically resize when I make the widget of the TableView smaller the content should adapt
So if I use TableView and want to resize, I would have to shovel the content from one colum to another.
From what I understand, the columns also define the layout.
Would I be better of if I used a QGridLayout for this purpose?
Do I have to define a completely new model for QGridLayout?
Thanks for any help!
I am a newbie to QT and would appreciate your input a lot!
Qt's proposed solution to having a complex view in each cell of a table view is to use a custom delegate. Take a look at Star Delegate example, it demonstrates exactly this technique.
There are basically two options to proceed with a custom delegate: either you subclass QStyledItemDelegate (or its base class QItemDelegate if you need to draw the items of Qt's datatypes somewhat specially) or subclass QAbstractItemDelegate to have the full control over the delegate's appearance and behaviour.
However, your second requirement of automatic layout rearrangement on widget resizing suggests that your view doesn't really has to follow the underlying table's schema. Qt has a flow layout example which implements a layout with exactly this rearrange-on-resize property and I suppose the simplest approach would be just using this layout along with custom widgets representing the table model's cells. To make it happen you could implement a custom view class listening to the model's signals and creating/deleting widgets and updating the flow layout as necessary. This book, even though a little outdated nowadays as it covers Qt4, contains a chapter (#6) on implementing a custom view which is not a subclass of QAbstractItemView but is just a widget updating itself as its underlying model updates. To me it feels the right approach to your problem.
Related
I'm totally new to Qt, so I'd be glad to have a wide answer.
Here I drew up some model:
We have a kind of table that contains:
an integer value with a spinbox.
a cell with three(not specifically) grouped radio buttons
Editbox
A button that interacts with this particular editbox.
Also we have 2 buttons to add and remove items from the table.
I did some google search and found out that it can be done via QTableView.
Is there any way to put such complex structures into a cell? Must it be a separate class inherited from QTableView?
If you're going to have up to a hundred or maybe a few hundreds of elements in the table, then use QTableWidget.
If you're going to have too many elements (about thousands), then go for QTableView, and learn model-view programming.
The reason why I recommend QTableWidget is because you're a beginner. All you have to do there is create a widget, and use setCellWidget() and you're done.
If you have thousands of rows, then you're gonna have to draw the widgets yourself using QStyledItemDelegate, which will paint the widgets inside your QTableView. This is a very painful thing to do, but there's no way around it. The reasons you can find here.
I see at least three options to implement that in Qt:
Use a QtableView or QTableWidget and insert some custom controls in it. See comments made be other persons to your post
Use a QGridLayout and fill it with your controls by line and column
Make your own QWidget to store and manage the line elements (the spinbox, edit field, radio button) using a QHBoxLayout. You can design this in QtCreator, it can have it's own .ui. This could make it easy to handle the interaction between each QWidget of a line (directly handled by your QWidget class). Later, you can put an instance of it for every line you need in a QVBoxLayout.
Personnaly, I would go with the last option, but it may not work smartly if the controls of each line have different content/size (see comments), then first options should be prefered.
I want to implement my own Widgets for a QListView. Like this:
If i click on this widget i want to do something.
In time, I only have experience with the QML-Version of the ListView.
Can someone explain how to insert this widget to the a QListView?
Greetings
UPDATE
In my Project i want a GUI like this:
In my first ListView I want to show items, that has a ListView, too. The text of each item can to be update.
There are 2 ways:
Set custom widget for each index: QAbstractItemView::setIndexWidget. Note: there may be problems with interaction with widgets. This way is typically used only for displaying static content.
Create custom QStyledItemDelegate and override editorEvent method. See model-view programming for details.
Update:
I propose you next design:
Create widget with image list + "dynamic content" + labels
Create ScrollArea with vertical layout and add there widgets (1.)
(2.) is prefferable than simple listview, because listview doesn't design for such cases. Listview designed for showing some data, but not to be a container for other complex widgets.
Pros: you will have fully interactable widgets.
Cons: you need to code a bit ;)
I've been toying around with Qt and ran into a small issue.
I want to display a list of pictures as a table of icons. Right now, I'm doing this by subclassing QAbstractTableModel, and plugging it into a subclass of QTableView.
This, in my opinion, overly complicates the code, the model and the view (especially when trying to edit/append items). When trying to implement the model as a QAbstractListModel, the items are displayed as table rows.
Is there a way to make QTableView display items as columns, instead?
Edit: Such that the items are rendered in a single row from left to right, and wrapped to a new row.
Or is it preferable to use the table model for table views in any case and work around the issues?
It's worth mentioning I'm using C# bindings for Qt based on Qt Jambi.
The QListView has exactly the functionality you are talking about.
If you don't need any functionality specific to QTableView, then I would suggest switching.
If you set "isWrapping", then the list will start from the top, go down to the bottom, then wrap to a new column.
Set "flow" to LeftToRight to display the list in rows instead of columns
You might also need to set "resizeMode", instead of Fixed, to Adjust. Which will automatically move things around when the list is resized.
Hope that helps.
Just as a side note, here is FlowLayout example. So if you just want to display a set of images in a self-adjusting grid, this would do it for you without all the overhead of a list/table. However, it doesn't give you any selection/editing capabilities or anything just layout.
I don't understand something here. You implement TableModel, so you can prepare data for view in the most desirable way. Suppose you have data A,B,C,D, then you can return A(00),B(01),C(10),D(11), or for example A(00),C(01),B(10),D(11). Is it what you want to do?
I'm trying to display some cards into a QListView but I'm really having trouble understanding how to use Qt's model/view pattern, and I can't find any simple examples.
Basically, I have two classes:
Card - my "model" which contains the name of the card, id, etc.
CardWidget - can load and render a Card object (display the card name and other info)
So how can I use Card and CardWidget to display a list of cards into a ListView? Do I need to change something to my classes, or should QListView be able to display them directly?
If someone could show me the basic steps or point me in the right direction that would be perfect.
See the documentation of QAbstractItemDelegate, which has an example of rendering items in a QTableView.
Its not obvious what you are trying to do here - in a list view, you can render a view of an item which is not the same as having a widget in every cell.
An item delegate can provide a widget as an editor and also how to render a cell's contents.
If you actually want fixed widgets in the view, you could use QListView::openPersistentEditor on all the cells you want a fixed widget for. The item delegate should outline how to create an editor for the cell in question.
I've got a QTableView for which I want to display the last column always in edit mode. (It's a QComboBox where the user should be able to always change the value.)
I think I've seen the solution in the Qt documentation, but I can't find it anymore. Is there a simple way of doing it?
I think I could archive this effect by using openPersistentEditor() for every cell, but I'm looking for a better way. (Like specifying it only one time for the whole column.)
One way to get the automatic editing behaviour is to call the view's setEditTriggers() function with the QAbstractItemView::AllEditTriggers value.
To display the contents of a given column in a certain way, take a look at QAbstractItemView::setItemDelegateForColumn(). This will let you specify a custom delegate just for those items that need it. However, it won't automatically create an editor widget for each of them (there could in principle be thousands of them), but you could use the delegate to render each item in a way that makes it look like an editor widget.
There are two possibilities:
Using setIndexWidget, but Trolltech writes:
This function should only be used to
display static content within the
visible area corresponding to an item
of data. If you want to display custom
dynamic content or implement a custom
editor widget, subclass QItemDelegate
instead.
(And it breaks the Model/View pattern…)
Or using a delegate's paint method. But here you have to implement everything like enabled/disabled elements yourself.
The QAbstractItemModel::flags virtual function is called to test if an item is editable (see Qt::ItemIsEditable). Take a look at Making the Model Editable in the Model/View Programming documentation.
I can't see an easy way to do this, but you might be able to manage by using a delegate. I honestly don't know exactly how it would work, but you should be able to get something working if you try hard enough. If you get a proper delegate, you should be able to set it on a whole view, one cell of a view, or just a column or row.