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.
Related
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.
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 have a requirement in the TreeView where I have to show down arrow image when tree is collapsed and up arrow image when tree is expanded and this is applicable for each parent item in the tree.
My UI will have only 1 column and this arrow images i have to show at the end of the row.
I am using QTreeView and I can see expand and collapse signals.But it does have only index arguement.But I need item rectanlge details to show the image at the end of the row.Could you pls suggest is there any way to achieve this?
Thanks,
The simplest way would be to use QTreeView::setIndexWidget (inherited from QAbstractItemView). With this method, you can set your own widget to render the nodes.
If you have more sophisticated requirements, you need to implement a custom delegate. Please have a look at the QAbstractItemDelegate Class Reference and Designing Delegates. By the use of delegates, you have complete rendering control over your items.
I am creating my first app in QT and wanted to design a list. The listitem has two texts and one icon.
The problem is, i cant find any example or helping material, Only helping link i found is : Customize QListWidgetItem but i dont understand it. Although i have the same problem which this links points to...
What i understand is, i have two options:
1- Customize QListWidgetItem to use with QListWidget
2- Make some delegate to use with QListView
I was hoping to get started with option 1. Now in the link, some reply talks about "myItem" which is taking 2 texts as input. I want to know the implementation of "myItem".
In the link you posted, MyItem is just a normal QWidget. This means that you can create a widget in Qt Designer and then set that new widget you created as the widget that the QListWidgetItem should use for display. In the above example, MyItem takes two strings because there is a vertical layout with two labels in it (that's my assumption at least).
You should also note, and is discussed in the above link, that taking the approach of setting an item widget to use for every item in the list is an expensive thing to do in terms of performance and memory consumption. Because a QListWidget is a QListView, you can set an item delegate on it just like any other view and come out with a lighter weight solution (one instantiation of class vs. one instantiation for every item in your list)
Qt 4.5 (PyQt 4.6.1)
I'm looking for a widget similar to a QComboBox that automatically filters its entries to the ones starting with the input in the text field. There are around 300 items in the combo box.
I've tried two approaches:
QLineEdit with QCompleter
Advantages
Filtering the items works.
Disadvantages
Doesn't show a popup if the text field is empty.
Doesn't do inline completion.
Allows to insert items not in the list.
Editable QComboBox with insertion set to no
Advantages
Nice popup
Completes inline in the text field.
Disadvantages
No filtering
Input is only possible in either the text field or the popup. Clicking on the popup doesn't select the best-matching item in the popup.
What I need
A popup to select the items.
Slow tippers should be able to start tipping the name of an item and the popup switches to the best matching one.
Preferably I should filter the items so that only partially-matching items are shown.
Concerning you first try with QLineEdit, you can set the completionMode to do it inline.
For your second try, you can add a QCompleter object to you QCombBox in order to filter your items as you want.The QCompleter member of the QComboBox is to offer an easy way to use QCompleter.
Anyway, if you are not satisfied with this method, you can manage a QCompleter object by yourself. This allows you to choose how item list is display (using any views) and to define items order in the list. See basic QCompleter details.