评论中提到从
data()
返回指向
MyListItem
的指针到QML并在QML中访问和修改它。这要求你的
MyListItem
继承自
QObject
,并为每个要在QML中访问的成员添加一个
Q_PROPERTY
。还需要密切关注对象所有权(
QQmlEngine::ObjectOwnership
)。
还有另一种方法:实现
QAbstractListModel::setData()
和
QAbstractListModel::roleNames()
,并且模型内容可以从QML中更改,比如
model.roleName = foo
。
以下是最小工作示例,每次单击委托时将数量加倍:
C++:struct MyListItem
{
QString heading;
QString description;
int quantity;
};
class MyListModel : public QAbstractListModel
{
Q_OBJECT
Q_ENUMS(MyRoles)
public:
enum MyRoles {
HeadingRole = Qt::UserRole + 1,
DescriptionRole,
QuantityRole
};
using QAbstractListModel::QAbstractListModel;
QHash<int,QByteArray> roleNames() const override {
return { { HeadingRole, "heading" },
{ DescriptionRole, "description" },
{ QuantityRole, "quantity" },
};
}
int rowCount(const QModelIndex & parent = QModelIndex()) const override {
if (parent.isValid())
return 0;
return m_list.size();
}
bool setData(const QModelIndex &index, const QVariant &value, int role) override
{
if (!hasIndex(index.row(), index.column(), index.parent()) || !value.isValid())
return false;
MyListItem &item = m_list[index.row()];
if (role == DescriptionRole) item.description = value.toString();
else if (role == HeadingRole) item.heading = value.toString();
else if (role == QuantityRole) item.quantity = value.toInt();
else return false;
emit dataChanged(index, index, { role } );
return true ;
}
QVariant data(const QModelIndex & index, int role = Qt::DisplayRole) const override {
if (!hasIndex(index.row(), index.column(), index.parent()))
return {};
const MyListItem &item = m_list.at(index.row());
if (role == DescriptionRole) return item.description;
if (role == HeadingRole) return item.heading;
if (role == QuantityRole) return item.quantity;
return {};
}
private:
QVector<MyListItem> m_list = {
{ "heading 1", "description 1", 1 },
{ "heading 2", "description 2", 42 },
{ "heading 3", "description 3", 4711 }
};
};
QML:
ListView {
id: listView
anchors.fill: parent
model: MyListModel {}
delegate: Item {
implicitHeight: text.height
width: listView.width
Text {
id: text
text: model.heading + " " + model.description + " " + model.quantity
}
MouseArea {
anchors.fill: text
onClicked: {
model.quantity *= 2;
}
}
}
}
QList<MyListItem>
元素,而不是myListItem
作为 ListView 的代理。 - Zhigalin - Reinstate CMsQAbstractItemModel::roleNames
),返回MyListItem
并在onClick
事件中使用,如此处所述。 - m7913d