内容

• 公共类型
• 特性
• 公共函数
• 信号
• 详细描述

QItemModelBarDataProxy Class

Proxy class for presenting data in item models with Q3DBars . 更多...

头：	#include <QItemModelBarDataProxy>
Since:	QtDataVisualization 1.0
实例化：	ItemModelBarDataProxy
继承：	QBarDataProxy

• 所有成员列表，包括继承成员

公共类型

enum	MultiMatchBehavior { MMBFirst, MMBLast, MMBAverage, MMBCumulative }

特性

autoColumnCategories : bool autoRowCategories : bool columnCategories : QStringList columnRole : QString columnRolePattern : QRegularExpression columnRoleReplace : QString itemModel : QAbstractItemModel* multiMatchBehavior : MultiMatchBehavior rotationRole : QString rotationRolePattern : QRegularExpression

rotationRoleReplace : QString rowCategories : QStringList rowRole : QString rowRolePattern : QRegularExpression rowRoleReplace : QString useModelCategories : bool valueRole : QString valueRolePattern : QRegularExpression valueRoleReplace : QString

公共函数

	QItemModelBarDataProxy (QAbstractItemModel * itemModel , const QString & rowRole , const QString & columnRole , const QString & valueRole , const QString & rotationRole , const QStringList & rowCategories , const QStringList & columnCategories , QObject * parent = nullptr)
	QItemModelBarDataProxy (QAbstractItemModel * itemModel , const QString & rowRole , const QString & columnRole , const QString & valueRole , const QStringList & rowCategories , const QStringList & columnCategories , QObject * parent = nullptr)
	QItemModelBarDataProxy (QAbstractItemModel * itemModel , const QString & rowRole , const QString & columnRole , const QString & valueRole , const QString & rotationRole , QObject * parent = nullptr)
	QItemModelBarDataProxy (QAbstractItemModel * itemModel , const QString & rowRole , const QString & columnRole , const QString & valueRole , QObject * parent = nullptr)
	QItemModelBarDataProxy (QAbstractItemModel * itemModel , const QString & valueRole , QObject * parent = nullptr)
	QItemModelBarDataProxy (QAbstractItemModel * itemModel , QObject * parent = nullptr)
	QItemModelBarDataProxy (QObject * parent = nullptr)
virtual	~QItemModelBarDataProxy ()
bool	autoColumnCategories () const
bool	autoRowCategories () const
QStringList	columnCategories () const
int	columnCategoryIndex (const QString & category )
QString	columnRole () const
QRegularExpression	columnRolePattern () const
QString	columnRoleReplace () const
QAbstractItemModel *	itemModel () const
QItemModelBarDataProxy::MultiMatchBehavior	multiMatchBehavior () const
void	remap (const QString & rowRole , const QString & columnRole , const QString & valueRole , const QString & rotationRole , const QStringList & rowCategories , const QStringList & columnCategories )
QString	rotationRole () const
QRegularExpression	rotationRolePattern () const
QString	rotationRoleReplace () const
QStringList	rowCategories () const
int	rowCategoryIndex (const QString & category )
QString	rowRole () const
QRegularExpression	rowRolePattern () const
QString	rowRoleReplace () const
void	setAutoColumnCategories (bool enable )
void	setAutoRowCategories (bool enable )
void	setColumnCategories (const QStringList & categories )
void	setColumnRole (const QString & role )
void	setColumnRolePattern (const QRegularExpression & pattern )
void	setColumnRoleReplace (const QString & replace )
void	setItemModel (QAbstractItemModel * itemModel )
void	setMultiMatchBehavior (QItemModelBarDataProxy::MultiMatchBehavior behavior )
void	setRotationRole (const QString & role )
void	setRotationRolePattern (const QRegularExpression & pattern )
void	setRotationRoleReplace (const QString & replace )
void	setRowCategories (const QStringList & categories )
void	setRowRole (const QString & role )
void	setRowRolePattern (const QRegularExpression & pattern )
void	setRowRoleReplace (const QString & replace )
void	setUseModelCategories (bool enable )
void	setValueRole (const QString & role )
void	setValueRolePattern (const QRegularExpression & pattern )
void	setValueRoleReplace (const QString & replace )
bool	useModelCategories () const
QString	valueRole () const
QRegularExpression	valueRolePattern () const
QString	valueRoleReplace () const

信号

void	autoColumnCategoriesChanged (bool enable )
void	autoRowCategoriesChanged (bool enable )
void	columnCategoriesChanged ()
void	columnRoleChanged (const QString & role )
void	columnRolePatternChanged (const QRegularExpression & pattern )
void	columnRoleReplaceChanged (const QString & replace )
void	itemModelChanged (const QAbstractItemModel * itemModel )
void	multiMatchBehaviorChanged (QItemModelBarDataProxy::MultiMatchBehavior behavior )
void	rotationRoleChanged (const QString & role )
void	rotationRolePatternChanged (const QRegularExpression & pattern )
void	rotationRoleReplaceChanged (const QString & replace )
void	rowCategoriesChanged ()
void	rowRoleChanged (const QString & role )
void	rowRolePatternChanged (const QRegularExpression & pattern )
void	rowRoleReplaceChanged (const QString & replace )
void	useModelCategoriesChanged (bool enable )
void	valueRoleChanged (const QString & role )
void	valueRolePatternChanged (const QRegularExpression & pattern )
void	valueRoleReplaceChanged (const QString & replace )

详细描述

QItemModelBarDataProxy allows you to use QAbstractItemModel derived models as a data source for Q3DBars . It uses the defined mappings to map data from the model to rows, columns, and values of Q3DBars graph.

The data is resolved asynchronously whenever mappings or the model changes. QBarDataProxy::arrayReset () is emitted when the data has been resolved. However, when useModelCategories property is set to true, single item changes are resolved synchronously, unless the same frame also contains a change that causes the whole model to be resolved.

Mappings can be used in the following ways:

• 若 useModelCategories property is set to true, this proxy will map rows and columns of QAbstractItemModel directly to rows and columns of Q3DBars , and uses the value returned for Qt::DisplayRole as bar value by default. The value role to be used can be redefined if Qt::DisplayRole is not suitable.
• For models that do not have data already neatly sorted into rows and columns, such as QAbstractListModel based models, you can define a role from the model to map for each of row, column and value.
• If you do not want to include all data contained in the model, or the autogenerated rows and columns are not ordered as you wish, you can specify which rows and columns should be included and in which order by defining an explicit list of categories for either or both of rows and columns.

For example, assume that you have a custom QAbstractItemModel for storing various monthly values related to a business. Each item in the model has the roles "year", "month", "income", and "expenses". You could do the following to display the data in a bar graph:

// 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" -> "2006" // 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 << "2006" << "2007" << "2008" << "2009" << "2010" << "2011" << "2012";
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"));
					

If the fields of the model do not contain the data in the exact format you need, you can specify a search pattern regular expression and a replace rule for each role to get the value in a format you need. For more information how the replace using regular expressions works, see QString::replace (const QRegularExpression &rx, const QString &after) function documentation. Note that using regular expressions has an impact on the performance, so it's more efficient to utilize item models where doing search and replace is not necessary to get the desired values.

For example about using the search patterns in conjunction with the roles, see Qt Quick 2 Bars Example .

另请参阅 Qt Data Visualization 数据处理 .

成员类型文档编制

enum QItemModelBarDataProxy:: MultiMatchBehavior

Behavior types for QItemModelBarDataProxy::multiMatchBehavior 特性。

常量	值	描述
QItemModelBarDataProxy::MMBFirst	0	The value is taken from the first item in the item model that matches each row/column combination.
QItemModelBarDataProxy::MMBLast	1	The value is taken from the last item in the item model that matches each row/column combination.
QItemModelBarDataProxy::MMBAverage	2	The values from all items matching each row/column combination are averaged together and the average is used as the bar value.
QItemModelBarDataProxy::MMBCumulative	3	The values from all items matching each row/column combination are added together and the total is used as the bar value.

特性文档编制

autoColumnCategories : bool

This property holds whether column categories are generated automatically.

当设为 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 .

访问函数：

bool	autoColumnCategories () const
void	setAutoColumnCategories (bool enable )

通知程序信号：

void	autoColumnCategoriesChanged (bool enable )

autoRowCategories : bool

This property holds whether row categories are generated automatically.

当设为 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 .

访问函数：

bool	autoRowCategories () const
void	setAutoRowCategories (bool enable )

通知程序信号：

void	autoRowCategoriesChanged (bool enable )

columnCategories : QStringList

This property holds the column categories for the mapping.

访问函数：

QStringList	columnCategories () const
void	setColumnCategories (const QStringList & categories )

通知程序信号：

void	columnCategoriesChanged ()

columnRole : QString

This property holds the column role for the mapping.

访问函数：

QString	columnRole () const
void	setColumnRole (const QString & role )

通知程序信号：

void	columnRoleChanged (const QString & role )

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.

访问函数：

QRegularExpression	columnRolePattern () const
void	setColumnRolePattern (const QRegularExpression & pattern )

通知程序信号：

void	columnRolePatternChanged (const QRegularExpression & pattern )

另请参阅 columnRole and columnRoleReplace .

columnRoleReplace : QString

This property holds the replace 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.

访问函数：

QString	columnRoleReplace () const
void	setColumnRoleReplace (const QString & replace )

通知程序信号：

void	columnRoleReplaceChanged (const QString & replace )

另请参阅 columnRole and columnRolePattern .

itemModel : QAbstractItemModel *

This property holds the item model.

访问函数：

QAbstractItemModel *	itemModel () const
void	setItemModel (QAbstractItemModel * itemModel )

通知程序信号：

void	itemModelChanged (const QAbstractItemModel * itemModel )

multiMatchBehavior : MultiMatchBehavior

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

默认为 QItemModelBarDataProxy::MMBLast . 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::MMBCumulative .

访问函数：

QItemModelBarDataProxy::MultiMatchBehavior	multiMatchBehavior () const
void	setMultiMatchBehavior (QItemModelBarDataProxy::MultiMatchBehavior behavior )

通知程序信号：

void	multiMatchBehaviorChanged (QItemModelBarDataProxy::MultiMatchBehavior behavior )

rotationRole : QString

This property holds the rotation role for the mapping.

访问函数：

QString	rotationRole () const
void	setRotationRole (const QString & role )

通知程序信号：

void	rotationRoleChanged (const QString & role )

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.

访问函数：

QRegularExpression	rotationRolePattern () const
void	setRotationRolePattern (const QRegularExpression & pattern )

通知程序信号：

void	rotationRolePatternChanged (const QRegularExpression & pattern )

另请参阅 rotationRole and rotationRoleReplace .

rotationRoleReplace : QString

This property holds the replace 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.

访问函数：

QString	rotationRoleReplace () const
void	setRotationRoleReplace (const QString & replace )

通知程序信号：

void	rotationRoleReplaceChanged (const QString & replace )

另请参阅 rotationRole and rotationRolePattern .

rowCategories : QStringList

This property holds the row categories for the mapping.

访问函数：

QStringList	rowCategories () const
void	setRowCategories (const QStringList & categories )

通知程序信号：

void	rowCategoriesChanged ()

rowRole : QString

This property holds the row role for the mapping.

访问函数：

QString	rowRole () const
void	setRowRole (const QString & role )

通知程序信号：

void	rowRoleChanged (const QString & role )

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.

访问函数：

QRegularExpression	rowRolePattern () const
void	setRowRolePattern (const QRegularExpression & pattern )

通知程序信号：

void	rowRolePatternChanged (const QRegularExpression & pattern )

另请参阅 rowRole and rowRoleReplace .

rowRoleReplace : QString

This property holds the replace 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.

访问函数：

QString	rowRoleReplace () const
void	setRowRoleReplace (const QString & replace )

通知程序信号：

void	rowRoleReplaceChanged (const QString & replace )

另请参阅 rowRole and rowRolePattern .

useModelCategories : bool

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

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

访问函数：

bool	useModelCategories () const
void	setUseModelCategories (bool enable )

通知程序信号：

void	useModelCategoriesChanged (bool enable )

valueRole : QString

This property holds the value role for the mapping.

访问函数：

QString	valueRole () const
void	setValueRole (const QString & role )

通知程序信号：

void	valueRoleChanged (const QString & role )

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.

访问函数：

QRegularExpression	valueRolePattern () const
void	setValueRolePattern (const QRegularExpression & pattern )

通知程序信号：

void	valueRolePatternChanged (const QRegularExpression & pattern )

另请参阅 valueRole and valueRoleReplace .

valueRoleReplace : QString

This property holds the replace 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.

访问函数：

QString	valueRoleReplace () const
void	setValueRoleReplace (const QString & replace )

通知程序信号：

void	valueRoleReplaceChanged (const QString & replace )

另请参阅 valueRole and valueRolePattern .

成员函数文档编制

QItemModelBarDataProxy:: QItemModelBarDataProxy ( QAbstractItemModel * itemModel , const QString & rowRole , const QString & columnRole , const QString & valueRole , const QString & rotationRole , const QStringList & rowCategories , const QStringList & columnCategories , QObject * parent = nullptr)

Constructs QItemModelBarDataProxy with itemModel 和可选 parent . Proxy doesn't take ownership of the itemModel , as typically item models are owned by other controls. The role mappings are set with rowRole , columnRole , valueRole ，和 rotationRole . Row and column categories are set with rowCategories and columnCategories . This constructor also sets autoRowCategories and autoColumnCategories 为 false。

QItemModelBarDataProxy:: QItemModelBarDataProxy ( QAbstractItemModel * itemModel , const QString & rowRole , const QString & columnRole , const QString & valueRole , const QStringList & rowCategories , const QStringList & columnCategories , QObject * parent = nullptr)

Constructs QItemModelBarDataProxy with itemModel 和可选 parent . Proxy doesn't take ownership of the itemModel , as typically item models are owned by other controls. The role mappings are set with rowRole , columnRole ，和 valueRole . Row and column categories are set with rowCategories and columnCategories . This constructor also sets autoRowCategories and autoColumnCategories 为 false。

QItemModelBarDataProxy:: QItemModelBarDataProxy ( QAbstractItemModel * itemModel , const QString & rowRole , const QString & columnRole , const QString & valueRole , const QString & rotationRole , QObject * parent = nullptr)

Constructs QItemModelBarDataProxy with itemModel 和可选 parent . Proxy doesn't take ownership of the itemModel , as typically item models are owned by other controls. The role mappings are set with rowRole , columnRole , valueRole ，和 rotationRole .

QItemModelBarDataProxy:: QItemModelBarDataProxy ( QAbstractItemModel * itemModel , const QString & rowRole , const QString & columnRole , const QString & valueRole , QObject * parent = nullptr)

Constructs QItemModelBarDataProxy with itemModel 和可选 parent . Proxy doesn't take ownership of the itemModel , as typically item models are owned by other controls. The role mappings are set with rowRole , columnRole ，和 valueRole .

QItemModelBarDataProxy:: QItemModelBarDataProxy ( QAbstractItemModel * itemModel , const QString & valueRole , QObject * parent = nullptr)

Constructs QItemModelBarDataProxy with itemModel 和可选 parent . Proxy doesn't take ownership of the itemModel , as typically item models are owned by other controls. The value role is set to valueRole . This constructor is meant to be used with models that have data properly sorted in rows and columns already, so it also sets useModelCategories 特性为 true。

QItemModelBarDataProxy:: QItemModelBarDataProxy ( QAbstractItemModel * itemModel , QObject * parent = nullptr)

Constructs QItemModelBarDataProxy with itemModel 和可选 parent . Proxy doesn't take ownership of the itemModel , as typically item models are owned by other controls.

QItemModelBarDataProxy:: QItemModelBarDataProxy ( QObject * parent = nullptr)

Constructs QItemModelBarDataProxy with optional parent .

[虚拟] QItemModelBarDataProxy:: ~QItemModelBarDataProxy ()

销毁 QItemModelBarDataProxy .

[invokable] int QItemModelBarDataProxy:: columnCategoryIndex (const QString & category )

Returns the index of the specified category in column categories list. If the category is not found, -1 is returned.

注意： If the automatic column categories generation is in use, this method will not return a valid index before the data in the model is resolved for the first time.

注意： 此函数可以被援引，通过元对象系统和从 QML。见 Q_INVOKABLE .

void QItemModelBarDataProxy:: remap (const QString & rowRole , const QString & columnRole , const QString & valueRole , const QString & rotationRole , const QStringList & rowCategories , const QStringList & columnCategories )

变化 rowRole , columnRole , valueRole , rotationRole , rowCategories and columnCategories to the mapping.

[invokable] int QItemModelBarDataProxy:: rowCategoryIndex (const QString & category )

Returns the index of the specified category in row categories list. If the row categories list is empty, -1 is returned.

注意： If the automatic row categories generation is in use, this method will not return a valid index before the data in the model is resolved for the first time.

注意： 此函数可以被援引，通过元对象系统和从 QML。见 Q_INVOKABLE .

void QItemModelBarDataProxy:: setItemModel ( QAbstractItemModel * itemModel )

Sets the item model to itemModel . Does not take ownership of the model, but does connect to it to listen for changes.

注意： setter 函数对于特性 itemModel .

另请参阅 itemModel ().