digiKam Developer Documentation
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Digikam::DCategorizedSortFilterProxyModel Class Reference

This class lets you categorize a view. More...

+ Inheritance diagram for Digikam::DCategorizedSortFilterProxyModel:

Public Types

enum  AdditionalRoles { CategoryDisplayRole = 0x17CE990A , CategorySortRole = 0x27857E60 }
 

Public Member Functions

 DCategorizedSortFilterProxyModel (QObject *const parent=nullptr)
 
bool isCategorizedModel () const
 
void setCategorizedModel (bool categorizedModel)
 Enables or disables the categorization feature.
 
void setSortCategoriesByNaturalComparison (bool sortCategoriesByNaturalComparison)
 Set if the sorting using CategorySortRole will use a natural comparison in the case that strings were returned.
 
void sort (int column, Qt::SortOrder order=Qt::AscendingOrder) override
 Overridden from QSortFilterProxyModel.
 
bool sortCategoriesByNaturalComparison () const
 
int sortColumn () const
 
Qt::SortOrder sortOrder () const
 

Protected Member Functions

virtual int compareCategories (const QModelIndex &left, const QModelIndex &right) const
 This method compares the category of the left index with the category of the right index.
 
bool lessThan (const QModelIndex &left, const QModelIndex &right) const override
 Overridden from QSortFilterProxyModel.
 
virtual bool subSortLessThan (const QModelIndex &left, const QModelIndex &right) const
 This method has a similar purpose as lessThan() has on QSortFilterProxyModel.
 

Detailed Description

It is meant to be used along with DCategorizedView class.

In general terms all you need to do is to reimplement subSortLessThan() and compareCategories() methods. In order to make categorization work, you need to also call setCategorizedModel() class to enable it, since the categorization is disabled by default.

Member Enumeration Documentation

◆ AdditionalRoles

Enumerator
CategoryDisplayRole 

This role is used for asking the category to a given index.

Note
use printf "0x%08X\n" $(($RANDOM*$RANDOM)) to define additional roles.
CategorySortRole 

This role is used for sorting categories.

You can return a string or a long long value. Strings will be sorted alphabetically while long long will be sorted by their value. Please note that this value won't be shown on the view, is only for sorting purposes. What will be shown as "Category" on the view will be asked with the role CategoryDisplayRole.

Member Function Documentation

◆ compareCategories()

int Digikam::DCategorizedSortFilterProxyModel::compareCategories ( const QModelIndex &  left,
const QModelIndex &  right 
) const
protectedvirtual

Internally and if not reimplemented, this method will ask for left and right models for role CategorySortRole. In order to correctly sort categories, the data() method of the model should return a qlonglong (or numeric) value, or a QString object. QString objects will be sorted with QString::localeAwareCompare if sortCategoriesByNaturalComparison() is true.

Note
Please have present that: QString(QChar(QChar::ObjectReplacementCharacter)) > QString(QChar(QChar::ReplacementCharacter)) > [ all possible strings ] > QString();

This means that QString() will be sorted the first one, while QString(QChar(QChar::ObjectReplacementCharacter)) and QString(QChar(QChar::ReplacementCharacter)) will be sorted in last position.

Warning
Please note that data() method of the model should return always information of the same type. If you return a QString for an index, you should return always QStrings for all indexes for role CategorySortRole in order to correctly sort categories. You can't mix by returning a QString for one index, and a qlonglong for other.
Note
If you need a more complex layout, you will have to reimplement this method.
Returns
A negative value if the category of left should be placed before the category of right. 0 if left and right are on the same category, and a positive value if the category of left should be placed after the category of right.

Reimplemented in Digikam::ItemFilterModel, ShowFoto::ShowfotoFilterModel, and Digikam::ImportFilterModel.

◆ isCategorizedModel()

bool Digikam::DCategorizedSortFilterProxyModel::isCategorizedModel ( ) const
Returns
whether the model is categorized or not. Disabled by default.

◆ lessThan()

bool Digikam::DCategorizedSortFilterProxyModel::lessThan ( const QModelIndex &  left,
const QModelIndex &  right 
) const
overrideprotected

If you are subclassing DCategorizedSortFilterProxyModel, you will probably not need to reimplement this method.

It calls compareCategories() to sort by category. If the both items are in the same category (i.e. compareCategories returns 0), then subSortLessThan is called.

Returns
Returns true if the item left is less than the item right when sorting.
Warning
You usually won't need to reimplement this method when subclassing from DCategorizedSortFilterProxyModel.

◆ setCategorizedModel()

void Digikam::DCategorizedSortFilterProxyModel::setCategorizedModel ( bool  categorizedModel)
Parameters
categorizedModelwhether to enable or disable the categorization feature.

◆ setSortCategoriesByNaturalComparison()

void Digikam::DCategorizedSortFilterProxyModel::setSortCategoriesByNaturalComparison ( bool  sortCategoriesByNaturalComparison)

If enabled, QCollator will be used for sorting.

Parameters
sortCategoriesByNaturalComparisonwhether to sort using a natural comparison or not.

◆ sort()

void Digikam::DCategorizedSortFilterProxyModel::sort ( int  column,
Qt::SortOrder  order = Qt::AscendingOrder 
)
override

Sorts the source model using column for the given order.

◆ sortCategoriesByNaturalComparison()

bool Digikam::DCategorizedSortFilterProxyModel::sortCategoriesByNaturalComparison ( ) const
Returns
whether it is being used a natural comparison for sorting. Enabled by default.

◆ sortColumn()

int Digikam::DCategorizedSortFilterProxyModel::sortColumn ( ) const
Returns
the column being used for sorting.

◆ sortOrder()

Qt::SortOrder Digikam::DCategorizedSortFilterProxyModel::sortOrder ( ) const
Returns
the sort order being used for sorting.

◆ subSortLessThan()

bool Digikam::DCategorizedSortFilterProxyModel::subSortLessThan ( const QModelIndex &  left,
const QModelIndex &  right 
) const
protectedvirtual

It is used for sorting items that are in the same category.

Returns
Returns true if the item left is less than the item right when sorting.

Reimplemented in Digikam::ItemFilterModel, ShowFoto::ShowfotoFilterModel, and Digikam::ImportFilterModel.