2017-02-27 19:04 GMT+01:00 Alexander Dyagilev <alervd...@gmail.com>: > I have another ListView wich uses C++ model derived from another class - > QSqlQueryModel. > > The same things happens: model is not updated and existing items gets > damaged. E.g. model.id for an item was 2 and became 0 after a new item has > been added (all existing item's model.id becomes 0). > > Something very wrong is happening. Look like I misunderstand something...
This is just a wild guess, but could it be because you're using "id" for your role name, which is special in the QML world? Not sure how QML plays with that.. Elvis > > > On 2/27/2017 8:59 PM, Alexander Dyagilev wrote: > > Hello, > > I've created a question on SO but nobody answered still... > (http://stackoverflow.com/questions/42468811/qml-listview-is-not-updated-on-model-reset) > > Qt 5.8, Windows 10. > > Quick Controls 2 application. In QML I have a ListView with a model derived > from QAbstractListModel. > > In the model I have the following code: > > void MediaPlaylistModel::update() > { > beginResetModel(); > { > std::unique_lock<std::mutex> lock(m_mutex); > m_ids = m_playlist->itemsIds(); > } > endResetModel(); > } > > Nothing happens in QML view after calling this method: list is not updated. > If I go back and then forward (to the page with the ListView) - it'll > contain updated data. Model object instance is the same always. > > Am I doing something wrong? > > Update #2: > > C++ model code: > > MediaPlaylistModel::MediaPlaylistModel( > QSharedPointer<AbstractMediaPlaylist> playlist, > QObject *parent) : > base_t(parent), > m_playlist(playlist) > { > Q_ASSERT(m_playlist); > > connect(playlist.data(), &AbstractMediaPlaylist::changed, > this, &MediaPlaylistModel::update); > > update(); > } > > QHash<int, QByteArray> MediaPlaylistModel::roleNames() const > { > QHash<int, QByteArray> result; > result[IdRole] = "id"; > result[TitleRole] = "title"; > result[DurationRole] = "duration"; > return result; > } > > void MediaPlaylistModel::update() > { > Q_ASSERT_SAME_THREAD; > beginResetModel(); > { > std::unique_lock<std::mutex> lock(m_mutex); > m_ids = m_playlist->itemsIds(); > } > endResetModel(); > } > > int MediaPlaylistModel::rowCount( > const QModelIndex &parent) const > { > Q_UNUSED(parent); > std::unique_lock<std::mutex> lock(m_mutex); > return static_cast<int>(m_ids.size()); > } > > QVariant MediaPlaylistModel::data( > const QModelIndex &index, > int role) const > { > auto row = static_cast<size_t>(index.row()); > int id = 0; > > { > std::unique_lock<std::mutex> lock(m_mutex); > if (row >= m_ids.size()) > return QVariant(); > id = m_ids[row]; > } > > if (role == IdRole) > return id; > > QVariant result; > > auto item = m_playlist->item(id); > > switch(role) > { > case Qt::DisplayRole: > case TitleRole: > result = item.title; > break; > case DurationRole: > result = item.duration; > break; > } > > return result; > } > > QML code: > > import QtQuick 2.7 > import QtQuick.Controls 2.0 > import com.company.application 1.0 > > Page > { > id : root > > property int playlistId > property var playlistApi: App.playlists.playlist(playlistId) > > ListView > { > id : playlist > anchors.fill: parent > model: playlistApi.model > delegate: ItemDelegate > { > text: model.title > width: parent.width > onClicked: App.player.play(playlistId, model.id) > } > ScrollIndicator.vertical: ScrollIndicator {} > } > } > > Update #3: > > When the model is updated (one item added), something strange happens with > QML ListView: in addition to fact that it's not updated (and it does not > call MediaPlaylistModel::data to retrieve new items), existing items got > damaged. When I click on existed item, it's model.id property is always 0. > E.g. at app start its model.id was 24, after one item added its model.id > became 0. > > Update #4: > > App.playlists.playlist(playlistId) returns pointer to this class instance: > > class CppQmlPlaylistApi : > public QObject > { > Q_OBJECT > Q_PROPERTY(QObject* model READ model NOTIFY modelChanged) > Q_PROPERTY(QString title READ title WRITE setTitle NOTIFY titleChanged) > > public: > explicit CppQmlPlaylistApi( > int playlistId, > QWeakPointer<CorePlaylistsManager> playlistsMgr, > QObject *parent = 0); > > QObject* model() const; > > QString title() const; > void setTitle(const QString &title); > > signals: > void modelChanged(); > void titleChanged(); > void loadPlaylistRequested(int id); > > protected slots: > void onPlaylistLoaded(int id); > void onPlaylistRemoved(int id); > > protected: > int m_playlistId = 0; > QWeakPointer<CorePlaylistsManager> m_playlistsMgr; > QSharedPointer<QAbstractItemModel> m_model; > }; > > > > _______________________________________________ > Interest mailing list > Interest@qt-project.org > http://lists.qt-project.org/mailman/listinfo/interest > _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
