QItemModelBarDataProxy Class

// By defining row and column categories, you tell the mapping which row and column each item
// belongs to. The categories must match the data stored in the model in the roles you define
// for row and column mapping. In this example we expect "year" role to return four digit year
// and "month" to return three letter designation for the month.
//
// An example of an item in model would be:
// Requested role -> Returned data
// "year" -> "2016" // Matches the first row category, so this item is added to the first row.
// "month" -> "jan" // Matches the first column category, so this item is added as first item in the row.
// "income" -> "12.1"
// "expenses" -> "9.2"
QStringList years;
QStringList months;
years << "2016" << "2017" << "2018" << "2019" << "2020" << "2021" << "2022";
months << "jan" << "feb" << "mar" << "apr" << "may" << "jun" << "jul" << "aug" << "sep" << "oct" << "nov" << "dec";

QItemModelBarDataProxy *proxy = new QItemModelBarDataProxy(customModel,
                                                           QStringLiteral("year"), // Row role
                                                           QStringLiteral("month"), // Column role
                                                           QStringLiteral("income"), // Value role
                                                           years, // Row categories
                                                           months); // Column categories

//...

// To display different data later, you can simply change the mapping.
proxy->setValueRole(QStringLiteral("expenses"));

Property Documentation

autoColumnCategories : bool

This property holds whether column categories are generated automatically.

When set to true, the mapping ignores any explicitly set column categories and overwrites them with automatically generated ones whenever the data from model is resolved. Defaults to true.

Access functions:

Notifier signal:

autoRowCategories : bool

This property holds whether row categories are generated automatically.

When set to true, the mapping ignores any explicitly set row categories and overwrites them with automatically generated ones whenever the data from model is resolved. Defaults to true.

Access functions:

Notifier signal:

columnCategories : QStringList

This property holds the column categories for the mapping.

Access functions:

Notifier signal:

columnRole : QString

This property holds the column role for the mapping.

Access functions:

Notifier signal:

columnRolePattern : QRegularExpression

This property holds whether a search and replace is done on the value mapped by column role before it is used as a column category.

This property specifies the regular expression to find the portion of the mapped value to replace and columnRoleReplace property contains the replacement string. This is useful for example in parsing row and column categories from a single timestamp field in the item model.

Access functions:

Notifier signal:

See also columnRole and columnRoleReplace.

columnRoleReplace : QString

This property holds the replacement content to be used in conjunction with columnRolePattern.

Defaults to empty string. For more information on how the search and replace using regular expressions works, see QString::replace(const QRegularExpression &rx, const QString &after) function documentation.

Access functions:

Notifier signal:

See also columnRole and columnRolePattern.

itemModel : QAbstractItemModel*

This property holds the item model.

Access functions:

Notifier signal:

multiMatchBehavior : QItemModelBarDataProxy::MultiMatchBehavior

How multiple matches for each row/column combination are handled.

Defaults to QItemModelBarDataProxy::MultiMatchBehavior::Last. The chosen behavior affects both bar value and rotation.

For example, you might have an item model with timestamped data taken at irregular intervals and you want to visualize total value of data items on each day with a bar graph. This can be done by specifying row and column categories so that each bar represents a day, and setting multiMatchBehavior to QItemModelBarDataProxy::MultiMatchBehavior::Cumulative.

Access functions:

Notifier signal:

rotationRole : QString

This property holds the rotation role for the mapping.

Access functions:

Notifier signal:

rotationRolePattern : QRegularExpression

This property holds whether a search and replace is done on the value mapped by rotation role before it is used as a bar rotation angle.

This property specifies the regular expression to find the portion of the mapped value to replace and rotationRoleReplace property contains the replacement string.

Access functions:

Notifier signal:

See also rotationRole and rotationRoleReplace.

rotationRoleReplace : QString

This property holds the replacement content to be used in conjunction with rotationRolePattern.

Defaults to empty string. For more information on how the search and replace using regular expressions works, see QString::replace(const QRegularExpression &rx, const QString &after) function documentation.

Access functions:

Notifier signal:

See also rotationRole and rotationRolePattern.

rowCategories : QStringList

This property holds the row categories for the mapping.

Access functions:

Notifier signal:

rowRole : QString

This property holds the row role for the mapping.

Access functions:

Notifier signal:

rowRolePattern : QRegularExpression

This property holds whether a search and replace is performed on the value mapped by row role before it is used as a row category.

This property specifies the regular expression to find the portion of the mapped value to replace and rowRoleReplace property contains the replacement string. This is useful for example in parsing row and column categories from a single timestamp field in the item model.

Access functions:

Notifier signal:

See also rowRole and rowRoleReplace.

rowRoleReplace : QString

This property holds the replacement content to be used in conjunction with rowRolePattern.

Defaults to empty string. For more information on how the search and replace using regular expressions works, see QString::replace(const QRegularExpression &rx, const QString &after) function documentation.

Access functions:

Notifier signal:

See also rowRole and rowRolePattern.

useModelCategories : bool

This property holds whether row and column roles and categories are used for mapping.

When set to true, the mapping ignores row and column roles and categories, and uses the rows and columns from the model instead. Defaults to false.

Access functions:

Notifier signal:

valueRole : QString

This property holds the value role for the mapping.

Access functions:

Notifier signal:

valueRolePattern : QRegularExpression

This property holds whether a search and replace is done on the value mapped by value role before it is used as a bar value.

This property specifies the regular expression to find the portion of the mapped value to replace and valueRoleReplace property contains the replacement string.

Access functions:

Notifier signal:

See also valueRole and valueRoleReplace.

valueRoleReplace : QString

This property holds the replacement content to be used in conjunction with valueRolePattern.

Defaults to empty string. For more information on how the search and replace using regular expressions works, see QString::replace(const QRegularExpression &rx, const QString &after) function documentation.

Access functions:

Notifier signal:

See also valueRole and valueRolePattern.