diff options
author | Jørgen Lind <jorgen.lind@nokia.com> | 2010-08-03 10:53:57 (GMT) |
---|---|---|
committer | Jørgen Lind <jorgen.lind@nokia.com> | 2010-08-03 10:53:57 (GMT) |
commit | d5491ecdde14659a913c9f476f18c45f1d9489bb (patch) | |
tree | 06cc52249feda9bd9e50ca47abb8ebd676c8a309 /doc/src/declarative/qdeclarativemodels.qdoc | |
parent | 42cdfaf86d34afeb6448723839fef70fe477deed (diff) | |
parent | a41128af5373a0225c3548abd3eb82cd7e8f7a0e (diff) | |
download | Qt-d5491ecdde14659a913c9f476f18c45f1d9489bb.zip Qt-d5491ecdde14659a913c9f476f18c45f1d9489bb.tar.gz Qt-d5491ecdde14659a913c9f476f18c45f1d9489bb.tar.bz2 |
Merge branch '4.7' of scm.dev.nokia.troll.no:qt/qt into lighthouse
Conflicts:
configure
Diffstat (limited to 'doc/src/declarative/qdeclarativemodels.qdoc')
-rw-r--r-- | doc/src/declarative/qdeclarativemodels.qdoc | 89 |
1 files changed, 87 insertions, 2 deletions
diff --git a/doc/src/declarative/qdeclarativemodels.qdoc b/doc/src/declarative/qdeclarativemodels.qdoc index b44e6f2..173002a 100644 --- a/doc/src/declarative/qdeclarativemodels.qdoc +++ b/doc/src/declarative/qdeclarativemodels.qdoc @@ -208,7 +208,10 @@ Models can be defined in C++ and then made available to QML. This is useful for exposing existing C++ data models or otherwise complex datasets to QML. A C++ model class can be defined as a QStringList, a QList<QObject*> or a -QAbstractItemModel. +QAbstractItemModel. The first two are useful for exposing simpler datasets, +while QAbstractItemModel provides a more flexible solution for more complex +models. + \section2 QStringList @@ -268,7 +271,10 @@ the model by calling QDeclarativeContext::setContextProperty() again. \section2 QAbstractItemModel -A model can be defined by subclassing QAbstractItemModel. +A model can be defined by subclassing QAbstractItemModel. This is the +best approach if you have a more complex model that cannot be supported +by the other approaches. A QAbstractItemModel can also automatically +notify a QML view when the model data has changed. The roles of a QAbstractItemModel subclass can be exposed to QML by calling QAbstractItemModel::setRoleNames(). The default role names set by Qt are: @@ -305,6 +311,12 @@ roles: \snippet examples/declarative/modelviews/abstractitemmodel/view.qml 0 +QML views are automatically updated when the model changes. Remember the model +must follow the standard rules for model changes and notify the view when +the model has changed by using QAbstractItemModel::dataChanged(), +QAbstractItemModel::beginInsertRows(), etc. See the \l {Model subclassing reference} for +more information. + The complete example is available in Qt's \l {declarative/modelviews/abstractitemmodel}{examples/declarative/modelviews/abstractitemmodel} directory. QAbstractItemModel presents a hierarchy of tables, but the views currently provided by QML @@ -429,4 +441,77 @@ Rectangle { } \endcode +\section1 Accessing Views and Models from Delegates + +You can access the view for which a delegate is used, and its +properties, by using ListView.view in a delegate on a ListView, or +GridView.view in a delegate on a GridView, etc. In particular, you can +access the model and its properties by using ListView.view.model. + +This is useful when you want to use the same delegate for a number of +views, for example, but you want decorations or other features to be +different for each view, and you would like these different settings to +be properties of each of the views. Similarly, it might be of interest +to access or show some properties of the model. + +In the following example, the delegate shows the property \e{language} +of the model, and the color of one of the fields depends on the +property \e{fruit_color} of the view. + +\code +Rectangle { + width: 200; height: 200 + + ListModel { + id: fruitModel + property string language: "en" + ListElement { + name: "Apple" + cost: 2.45 + } + ListElement { + name: "Orange" + cost: 3.25 + } + ListElement { + name: "Banana" + cost: 1.95 + } + } + + Component { + id: fruitDelegate + Row { + Text { text: " Fruit: " + name; color: ListView.view.fruit_color } + Text { text: " Cost: $" + cost } + Text { text: " Language: " + ListView.view.model.language } + } + } + + ListView { + property color fruit_color: "green" + model: fruitModel + delegate: fruitDelegate + anchors.fill: parent + } +} +\endcode + +Another important case is when some action (e.g. mouse click) in the +delegate should update data in the model. In this case you can define +a function in the model, e.g.: + +\code + setData(int row, const QString & field_name, QVariant new_value), +\endcode + +...and call it from the delegate using: + +\code + ListView.view.model.setData(index, field, value) +\endcode + +...assuming that \e{field} holds the name of the field which should be +updated, and that \e{value} holds the new value. + */ |