examples-barmodelmapper.qdoc
57 lines
| 3.1 KiB
| text/plain
|
TextLexer
Marek Rosa
|
r1369 | /*! | ||
| \example examples/barmodelmapper | ||||
| \title BarModelMapper example | ||||
| \subtitle | ||||
| This example shows how to use QAbstractItemModel derived model as the data for the bar series. | ||||
|
Marek Rosa
|
r1393 | \image examples_barmodelmapper.png | ||
|
Marek Rosa
|
r1369 | Let's start by creating an instance of CustomTableModel class. | ||
| CustomTableModel class is derived from QAbstractTableModel and it was created for the purpose of this example. | ||||
| The constructor of this class populates the internal data store of the model with the data that is good for our chart example. | ||||
| \snippet ../examples/barmodelmapper/tablewidget.cpp 1 | ||||
| We now have a model with data that we would like to display both on the chart and in a QTableView. | ||||
|
Marek Rosa
|
r1393 | First, we create QTableView and tell it use the model as a data source. To have the data presented nicely the minimum width of the table view is set and its headers resize mode changed to stretch. | ||
|
Marek Rosa
|
r1369 | |||
| \snippet ../examples/barmodelmapper/tablewidget.cpp 2 | ||||
| Now we need QChart instance to display the same data on the chart. | ||||
| We also enable animations. It makes it easier to see how modifying the model's data affect the chart. | ||||
| \snippet ../examples/barmodelmapper/tablewidget.cpp 3 | ||||
sauimone
|
r1618 | First line of the code below creates new bar series. Variables firstRow and rowCount are used to define a custom model mapping. | ||
|
Marek Rosa
|
r1369 | Custom mapping allows to take only part of the data from the model. In this case data from 5 rows starting with the row with the index 3. | ||
|
Marek Rosa
|
r1406 | Following three lines create an instance of QVBarModelMapper class and specifie that data for the bar sets should be taken from the model's columns with indexes from 1 to 4(inclusive). | ||
|
Marek Rosa
|
r1369 | To create a connection between the series and the model we set both of those objects to QVBarModelMapper. | ||
| Finally the series is added to the chart. | ||||
| \snippet ../examples/barmodelmapper/tablewidget.cpp 4 | ||||
|
Marek Rosa
|
r1406 | To show in QTableView which data coresponds with which bar set this example uses table coloring. | ||
|
Marek Rosa
|
r1369 | When series is added to the chart it is assigned a color beased on the currently selected theme. | ||
| Code below extracts that color from the series and uses it to create colored QTableView. | ||||
| Coloring of the view is not a part of the QChart functionality. | ||||
| \snippet ../examples/barmodelmapper/tablewidget.cpp 5 | ||||
| We would like to have categories placed on the chart's axis that describe what the data means. | ||||
| Next snippet shows how to do that. | ||||
| \snippet ../examples/barmodelmapper/tablewidget.cpp 6 | ||||
| To avoid setting up the QGraphicsScene we use QChartView class that does it for us. QChart object pointer is used as a parameter of the QChartView constructor. | ||||
| To make the render look nicer Antialiasing is turned on and the minimum size of the chartView widget is set. | ||||
| \snippet ../examples/barmodelmapper/tablewidget.cpp 7 | ||||
| Finally we place both widgets in a layout and use the layout as the application layout. | ||||
| \snippet ../examples/barmodelmapper/tablewidget.cpp 8 | ||||
| Application is ready. Try modifying the data in the table view and see how it affects the chart. | ||||
| */ | ||||