LuaModel class reference
[Model/View module]

Declaration

#include <QtLua/UserItemModel>

namespace QtLua {
  class LuaModel;
};

This class is a member of the QtLua namespace.

This class is declared in QtLua/qtlualuamodel.hh source file, line 141.

Description

This class allows defining a Qt model using lua code. Lua functions must be provided to the C++ model wrapper in order to implement the model.

The qt.mvc.new_lua_model lua function can be used to create such a model from lua script.

read-only lua model

At least one lua function must be provided to implement a read-only model. This mandatory function is responsible for exposing the model layout and data:

function get(role, item_id, child_row, child_col)

The get function may be first called multiple times by the wrapper with a nil value in the role parameter. In this case, the lua code must expose the data layout:

role is a nil value.
item_id is the numerical id of the queried item. 0 is reserved for root.
child_row and child_col are the row and column of a child item under the queried item, starting at 1.

The lua code must then return at least 3 values. This is enough if the queried item has no parent:

return (item_rows, item_cols, child_id, parent_id, item_row, item_col, flags)

item_rows and item_cols are the number of rows and columns under the item specified by item_id.
child_id is a numerical id for the child item at position specified by child_row and child_col under the queried item. A positive id must provided by the lua code and will be used to refer to this item later.
parent_id is the numerical id of the parent of the item specified by item_id. nil or 0 can be returned for root.
item_row and item_col give the position of the item specified by item_id in its parent, starting at 1. This is not used if parent_id is nil or 0.
flags is the Qt::ItemFlag value to use for the queried item. A default value is used if nil.

If the role parameter is not a nil value, the get function must instead return the data associated with the specified the display role:

return (item_data, data_type)

If the lua code returns two values, the second value is a numeric Qt type handle which is used to perform the type conversion from the lua the value (see qt.meta_type). The simple ValueBase::to_qvariant function is used to perform conversion when this hint is not present.

editable lua model

Five other functions may be provided to implement an editable model.

The set function is responsible for updating the data of an item; it must return true if the update was successful:

function set(role, item_id, value)

Four more function can be provided to support insertion and removal of items in the model:

function insert_rows(check, parent_id, pos, count)
function insert_cols(check, parent_id, pos, count)
function remove_rows(check, parent_id, pos, count)
function remove_cols(check, parent_id, pos, count)

When the check parameter value is true, the model must return a boolean value to indicate if the insert action is allowed. The insertion will takes place on the next call if the first call returns true.

Examples

Some examples of lua list model and tree model are available in the QtLua tree.

Members

Type

enum ItemDataRole

Function

LuaModel(const Value &get_func, const Value &set_func = [...], const Value &insert_rows_func = [...], const Value &remove_rows_func = [...], const Value &insert_cols_func = [...], const Value &remove_cols_func = [...], QObject *parent = [...])

Private functions

void cached_get(intptr_t item_id, int child_row, int child_col) const
int columnCount(const QModelIndex &parent) const
QVariant data(const QModelIndex &index, int role) const
void error(const String &err) const
Qt::ItemFlags flags(const QModelIndex &index) const
QModelIndex index(int row, int column, const QModelIndex &parent) const
bool insertColumns(int col, int count, const QModelIndex &parent)
bool insertRows(int row, int count, const QModelIndex &parent)
QModelIndex parent(const QModelIndex &index) const
bool removeColumns(int col, int count, const QModelIndex &parent)
bool removeRows(int row, int count, const QModelIndex &parent)
int rowCount(const QModelIndex &parent) const
bool setData(const QModelIndex &index, const QVariant &value, int role)

Private fields

int _child_col
int _child_row
Value _get
Value _insert_cols
Value _insert_rows
intptr_t _item_id
Value _remove_cols
Value _remove_rows
intptr_t _res[7]
int _rsize
Value _set

Members detail

LuaModel(const Value &get_func, const Value &set_func = Value(), const Value &insert_rows_func = Value(), const Value &remove_rows_func = Value(), const Value &insert_cols_func = Value(), const Value &remove_cols_func = Value(), QObject *parent = 0)

This constructor is declared in QtLua/qtlualuamodel.hh source file, line 153.

enum ItemDataRole

This enum is declared in QtLua/qtlualuamodel.hh source file, line 156.

Identifier	Value	Description
DisplayRole	::Qt::DisplayRole
DecorationRole	::Qt::DecorationRole
EditRole	::Qt::EditRole
ToolTipRole	::Qt::ToolTipRole
StatusTipRole	::Qt::StatusTipRole
WhatsThisRole	::Qt::WhatsThisRole
FontRole	::Qt::FontRole
TextAlignmentRole	::Qt::TextAlignmentRole
BackgroundColorRole	::Qt::BackgroundColorRole
BackgroundRole	::Qt::BackgroundRole
TextColorRole	::Qt::TextColorRole
ForegroundRole	::Qt::ForegroundRole
CheckStateRole	::Qt::CheckStateRole
AccessibleTextRole	::Qt::AccessibleTextRole
AccessibleDescriptionRole	::Qt::AccessibleDescriptionRole
SizeHintRole	::Qt::SizeHintRole
InitialSortOrderRole	::Qt::InitialSortOrderRole
UserRole	::Qt::UserRole