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The QItemDelegate class provides display and editing facilities for data items from a model. QItemDelegate can be used to provide custom display features and editor widgets for item views based on QAbstractItemView subclasses.

Using a delegate for this purpose allows the display and editing mechanisms to be customized and developed independently from the model and view. We recommend the use of QStyledItemDelegate when creating new delegates.

When displaying items from a custom model in a standard view, it is often sufficient to simply ensure that the model returns appropriate data for each of the roles that determine the appearance of items in views. The default delegate used by Qt's standard views uses this role information to display items in most of the common forms expected by users. However, it is sometimes necessary to have even more control over the appearance of items than the default delegate can provide. Looks good.

We're on track! When a new instance of MyDelegate created, it does not have the methods to use to make it functiioning i. As we can see from the table below, we need to re-implement couple of virtual methods inherited from QItemDelegate class. So, the prototypes for the inherited virtual member functions are done. Now, let our dialog know we now have a new delegate class:. Most of the things seem to work. However, note that the SpinBox we see is not properly located.

That's because we haven't finished the Geometry for Editor. Let's do that now. Also, after we changed the value in the SpinBox, it's not put that value back to the Model.

Here is the file used in this tutorial: DelegateTableView. Toggle navigation BogoToBogo. Sponsor Open Source development activities and free contents for everyone. Thank you.A QTableView implements a table view that displays items from a model. You can navigate the cells in the table by clicking on a cell with the mouse, or by using the arrow keys. The table has a vertical header that can be obtained using the verticalHeader function, and a horizontal header that is available through the horizontalHeader function.

The height of each row in the table can be found by using rowHeight ; similarly, the width of columns can be found using columnWidth. Since both of these are plain widgets, you can hide either of them using their hide functions.

Rows and columns can be hidden and shown with hideRowhideColumnshowRowand showColumn. They can be selected with selectRow and selectColumn.

Model/View Tutorial

The table will show a grid depending on the showGrid property. The items shown in a table view, like those in the other item views, are rendered and edited using standard delegates. However, for some tasks it is sometimes useful to be able to insert widgets in a table instead.

Widgets are set for particular indexes with the setIndexWidget function, and later retrieved with indexWidget. You can make the cells fill the available space by stretching the last header section. Access the relevant header using horizontalHeader or verticalHeader and set the header's stretchLastSection property. To distribute the available space according to the space requirement of each column or row, call the view's resizeColumnsToContents or resizeRowsToContents functions.

For some specialized forms of tables it is useful to be able to convert between row and column indexes and widget coordinates. The rowAt function provides the y-coordinate within the view of the specified row; the row index can be used to obtain a corresponding y-coordinate with rowViewportPosition. The columnAt and columnViewportPosition functions provide the equivalent conversion operations between x-coordinates and column indexes.

If this property is true then button in the top-left corner of the table view is enabled. Clicking on this button will select all the cells in the table view. This property holds the style used when drawing the grid see showGrid. If this property is true a grid is drawn for the table; if the property is falseno grid is drawn. The default value is true. If this property is truesorting is enabled for the table. If this property is falsesorting is not enabled. The default value is false. Setting the property to true with setSortingEnabled immediately triggers a call to sortByColumn with the current sort section and order.

If this property is true then the item text is wrapped where necessary at word-breaks; otherwise it is not wrapped at all. This property is true by default. Note that even of wrapping is enabled, the cell will not be expanded to fit all text.

Ellipsis will be inserted according to the current textElideMode. This slot is called whenever columns are added or deleted. The previous number of columns is specified by oldCountand the new number of columns is specified by newCount. This slot is called to change the index of the given column in the table view. The old index is specified by oldIndexand the new index by newIndex.

This slot is called to change the width of the given column. The old width is specified by oldWidthand the new width by newWidth. See also showColumn and hideRow. See also showRow and hideColumn. Resizes the given column based on the size hints of the delegate used to render each item in the column.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here.

Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. The model also has a timer attached to it, which upon expiring, gets the number of rows and columns, constructs an index for it, and emits dataChanged signal, to update the dynamic contents of the table.

In that case, even though I obtain a new index with the changed no. I've identified why, perhaps. Let's say I have 2 rows in the beginning, and next, 5 rows are supposed to be displayed.

In the timer expiration logic, I've asked it to construct a new index, with new row count… but dataChanged signal, will only change the data for the rows which had already been inserted in the first. The new rows are not displayed. Just because you create a QModelIndex to the element at row, coldoesn't mean you created data for that element and also not for the elements between the current end and that element.

You have to use setData Learn more. Asked 7 years, 1 month ago. Active 2 years ago. Viewed 4k times. The model starts out with a number of rows and displays the data properly. The problem is when the number of rows it is supposed to display, changes. This is my code for the model. Active Oldest Votes.

PrisonMonkeys PrisonMonkeys 7 7 silver badges 18 18 bronze badges. In this case, I'd wish to remove all the rows and insert new ones If a reset is to be done, where should I do it? So in the timerHit slot, if I store the number of rows, and then if the new row count is different from the old, should I call beginResetModel.

Is this correct? Else, where should I have it? I don't completely understand what you are trying to do. If you really want to erase everything from the model, then I think you have to remove all the rows separately.

And after that you can start inserting rows againg. If you just want your view to do a complete update based on the data in the model, just use QAbstractTableModel::modelReset.Every UI developer should know about ModelView programming and the goal of this tutorial is to provide you with an easily understandable introduction to this topic.

Table, list and tree widgets are components frequently used in GUIs. There are 2 different ways how these widgets can access their data. The traditional way involves widgets which include internal containers for storing data. This approach is very intuitive, however, in many non-trivial applications, it leads to data synchronization issues. They access external data through a standardized interface and therefore avoid data duplication.

This tutorial includes example code for you to edit and integrate into your project. For more detailed information you may also want to look at the reference documentation.

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If you are completely new to Qt, please read How to Learn Qt if you have not already done so. Standard widgets are not designed for separating data from views and this is why Qt 4 has two different types of widgets. Both types of widgets look the same, but they interact with data differently. Let's have a closer look at a standard table widget. A table widget is a 2D array of the data elements that the user can change.

The table widget can be integrated into a program flow by reading and writing the data elements that the table widget provides. This method is very intuitive and useful in many applications, but displaying and editing a database table with a standard table widget can be problematic. Two copies of the data have to be coordinated: one outside the widget; one inside the widget. The developer is responsible for synchronizing both versions. Besides this, the tight coupling of presentation and data makes it harder to write unit tests.

In fact, they operate directly from your data. Since view classes do not know your data's structure, you need to provide a wrapper to make your data conform to the QAbstractItemModel interface. A view uses this interface to read from and write to your data.

Any instance of a class that implements QAbstractItemModel is said to be a model.

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Once the view receives a pointer to a model, it will read and display its content and be its editor. We can edit data stored in tables directly from within the table itself, but it's much more comfortable to edit data in text fields. QDataWidgetMapper is a great solution because it maps form widgets to a table row and makes it very easy to build forms for database tables. Another example of an adapter is QCompleter. QCompleter uses a model as its data source. We recommend starting with a simple example and extending it step-by-step.

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This makes understanding the architecture a lot easier. Give it a try! Simply replace the data in the examples below with your own. We start with an application that uses a QTableView to show data. We will add editing capabilities later. Here is the interesting part: We create an instance of MyModel and use tableView.

QAbstractTableModel requires the implementation of three abstract methods. When the view has to know what the cell's text is, it calls the method MyModel::data.Chapter 3 - Create an empty QMainWindow. Chapter 5 - Add a chart view. Now that you have a QMainWindow, you can include a centralWidget to your interface. Usually, a QWidget is used to display data in most data-driven applications. Use a table view to display your data.

The first step is to add a horizontal layout with just a QTableView. Remember that a QTableView needs a model to display information. In this case, you can use a QAbstractTableModel instance. You could also use the default item model that comes with a QTableWidget instead. Implementing the model for your QTableView, allows you to: - set the headers, - manipulate the formats of the cell values remember we have UTC time and float numbers- set style properties like text alignment, - and even set color properties for the cell or its content.

To subclass the QAbstractTable, you must reimplement its virtual methods, rowCountcolumnCountand data. This way, you can ensure that the data is handled properly. In addition, reimplement the headerData method to provide the header information to the view. Documentation contributions included herein are the copyrights of their respective owners.

Qt and respective logos are trademarks of The Qt Company Ltd. All other trademarks are property of their respective owners. Qt for Python 5. Note You could also use the default item model that comes with a QTableWidget instead. BackgroundRole : return QColor Qt. TextAlignmentRole : return Qt. AlignRight return None. ResizeToContents self. PreferredQSizePolicy. Preferred Left layout size.

ArgumentParser options.More …. Inherited by: QTableWidget. A QTableView implements a table view that displays items from a model. You can navigate the cells in the table by clicking on a cell with the mouse, or by using the arrow keys.

The table has a vertical header that can be obtained using the verticalHeader function, and a horizontal header that is available through the horizontalHeader function. The height of each row in the table can be found by using rowHeight ; similarly, the width of columns can be found using columnWidth.

Since both of these are plain widgets, you can hide either of them using their hide functions. Rows and columns can be hidden and shown with hideRowhideColumnshowRowand showColumn. They can be selected with selectRow and selectColumn. The table will show a grid depending on the showGrid property. The items shown in a table view, like those in the other item views, are rendered and edited using standard delegates.

However, for some tasks it is sometimes useful to be able to insert widgets in a table instead. Widgets are set for particular indexes with the setIndexWidget function, and later retrieved with indexWidget.

You can make the cells fill the available space by stretching the last header section. For some specialized forms of tables it is useful to be able to convert between row and column indexes and widget coordinates. The rowAt function provides the y-coordinate within the view of the specified row; the row index can be used to obtain a corresponding y-coordinate with rowViewportPosition. The columnAt and columnViewportPosition functions provide the equivalent conversion operations between x-coordinates and column indexes.

Constructs a table view with a parent to represent the data. Returns the column in which the given x-coordinate, xin contents coordinates is located. This slot is called whenever columns are added or deleted. The previous number of columns is specified by oldCountand the new number of columns is specified by newCount.

This slot is called to change the index of the given column in the table view. The old index is specified by oldIndexand the new index by newIndex. This slot is called to change the width of the given column. The old width is specified by oldWidthand the new width by newWidth.

Returns the column span of the table element at rowcolumn. The default is 1. Returns the x-coordinate in contents coordinates of the given column. Returns the width of the given column. Hide the given column. Returns true if the given column is hidden; otherwise returns false. Returns true if the given row is hidden; otherwise returns false. Resizes the given column based on the size hints of the delegate used to render each item in the column.

Only visible columns will be resized. Reimplement sizeHintForColumn to resize hidden columns as well. Resizes all columns based on the size hints of the delegate used to render each item in the columns. Resizes the given row based on the size hints of the delegate used to render each item in the row. Returns the row in which the given y-coordinate, yin contents coordinates is located.

This slot is called whenever rows are added or deleted. The previous number of rows is specified by oldCountand the new number of rows is specified by newCount.Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you may not be able to execute some actions. Please download a browser that supports JavaScript, or enable it if it's disabled i.

The model also has a timer attached to it, which upon expiring, gets the number of rows and columns, constructs an index for it, and emits dataChanged signal, to update the dynamic contents of the table. In that case, even though I obtain a new index with the changed no. I've identified why, perhaps. Let's say I have 2 rows in the beginning, and next, 5 rows are supposed to be displayed.

In the timer expiration logic, I've asked it to ocnstruct a new index, with new row count The new rows are not displayed. This is my code for the model. Reset on the other hand will also reset any proxy model selection stuff. Just curious, but why don't you use ItemList as a QList? Deriving a QList is tricky though, so be carefull to do so. Then in rowCount etc you simple return the number of items in QList. After the endInsertRows the View will update the changed cells automatic.

One more thing. If you want remove some rows then add some new better use: beginResetModel ; No, you don't. It is better to really indicate which rows you are going to remove, and which ones you are adding instead of doing a model reset.

If possible at all, avoid model resets. They are very annoying for the user, as they cause large visual disruptions and loss of selections. Sure, if you need to completely rebuild your data, then a reset makes sense. But not if you only need to replace 10 rows out of or more.

Qt Documentation

Yes i agree with you : to starbearer: please read my older post as: One more thing. If you want remove all rows then add some new better use: beginResetModel ; In your case yes. But i don't understand something. Can you tell me why do you call data Ind1 row 26 in timerHit? And Data Ind1 was just something I'd been trying out, thinking it'd force the new rows to come up.

You need to inform any connected view that your data structure has changed. At the same time, the QAbstractItemModel knows nothing of your actual data, so it can't automatically do it. But i am pretty sure there are reasons for remove and add rows, between starting and resetting the model.

Maybe somebody with deep knowledge write the reasons :. This seems to work just fine. I'm not adding any rows or deleting any. When I get the information that the number of rows has changed, I merely reset the model and so on.

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It did the trick. This is weird code. Why do you say you are resetting the model when you actually don't do any resetting between your calls?