From 27c0e9d709aba97bd522fd3e53a53c4ff3c4d71b Mon Sep 17 00:00:00 2001 From: Shawn Rutledge Date: Wed, 19 Dec 2018 01:42:11 +0100 Subject: TableModel: add roleDataProvider callback As an alternative to trying to write smarter C++ in the data() accessor, we give the user full control of data conversion by calling an external JS function if defined, to map role to the value that data() should return. This enables extracting arbitrary values, converting the data in arbitrary ways, or even doing calculations in case the EditRole stores a formula and the DisplayRole should provide the result, or something like that. This callback is implemented somewhat like TableView.columnWidthProvider, but the arguments are more complex: function(row, column, role, rawData) Change-Id: Ifaf5807f4809e0b5ad1d1c403f65c0707b902f10 Reviewed-by: Mitch Curtis Reviewed-by: Shawn Rutledge --- src/qml/types/qqmltablemodel.cpp | 40 ++++++++++++++++++++++++++++++++++++++++ src/qml/types/qqmltablemodel_p.h | 6 ++++++ 2 files changed, 46 insertions(+) (limited to 'src/qml/types') diff --git a/src/qml/types/qqmltablemodel.cpp b/src/qml/types/qqmltablemodel.cpp index cf3fc0298a..9bf8c7f562 100644 --- a/src/qml/types/qqmltablemodel.cpp +++ b/src/qml/types/qqmltablemodel.cpp @@ -548,6 +548,38 @@ void QQmlTableModel::setRow(int rowIndex, const QVariant &row) } } +/*! + \qmlproperty var TableModel::roleDataProvider + + This property can hold a function that will map roles to values. + + When assigned, it will be called each time data() is called, to enable + extracting arbitrary values, converting the data in arbitrary ways, or even + doing calculations. It takes 4 arguments: \c row, \c column, \c role (as a + string), and \c cellData, which is the complete data that is stored in the + given cell. (If the cell contains a JS object with multiple named values, + the entire object will be given in cellData.) The function that you define + must return the value to be used; for example a typical delegate will + display the value returned for the \c display role, so you can check + whether that is the role and return data in a form that is suitable for the + delegate to show: + + \snippet qml/tablemodel/roleDataProvider.qml 0 +*/ +QJSValue QQmlTableModel::roleDataProvider() const +{ + return mRoleDataProvider; +} + +void QQmlTableModel::setRoleDataProvider(QJSValue roleDataProvider) +{ + if (roleDataProvider.strictlyEquals(mRoleDataProvider)) + return; + + mRoleDataProvider = roleDataProvider; + emit roleDataProviderChanged(); +} + QModelIndex QQmlTableModel::index(int row, int column, const QModelIndex &parent) const { return row >= 0 && row < rowCount() && column >= 0 && column < columnCount() && !parent.isValid() @@ -603,6 +635,14 @@ QVariant QQmlTableModel::data(const QModelIndex &index, int role) const return QVariant(); const QVariantList rowData = mRows.at(row).toList(); + + if (mRoleDataProvider.isCallable()) { + const auto args = QJSValueList() << row << column << + QString::fromUtf8(mRoleNames.value(role)) << + qmlEngine(this)->toScriptValue(rowData.at(column)); + return const_cast(this)->mRoleDataProvider.call(args).toVariant(); + } + const QVariantMap columnData = rowData.at(column).toMap(); int effectiveRole = role; diff --git a/src/qml/types/qqmltablemodel_p.h b/src/qml/types/qqmltablemodel_p.h index 8da930872d..863c592678 100644 --- a/src/qml/types/qqmltablemodel_p.h +++ b/src/qml/types/qqmltablemodel_p.h @@ -65,6 +65,7 @@ class Q_QML_PRIVATE_EXPORT QQmlTableModel : public QAbstractTableModel Q_PROPERTY(int columnCount READ columnCount NOTIFY columnCountChanged FINAL) Q_PROPERTY(int rowCount READ rowCount NOTIFY rowCountChanged FINAL) Q_PROPERTY(QVariant rows READ rows WRITE setRows NOTIFY rowsChanged FINAL) + Q_PROPERTY(QJSValue roleDataProvider READ roleDataProvider WRITE setRoleDataProvider NOTIFY roleDataProviderChanged) public: QQmlTableModel(QObject *parent = nullptr); @@ -81,6 +82,9 @@ public: Q_INVOKABLE void removeRow(int rowIndex, int rows = 1); Q_INVOKABLE void setRow(int rowIndex, const QVariant &row); + QJSValue roleDataProvider() const; + void setRoleDataProvider(QJSValue roleDataProvider); + QModelIndex index(int row, int column, const QModelIndex &parent) const override; int rowCount(const QModelIndex &parent = QModelIndex()) const override; int columnCount(const QModelIndex &parent = QModelIndex()) const override; @@ -92,6 +96,7 @@ Q_SIGNALS: void columnCountChanged(); void rowCountChanged(); void rowsChanged(); + void roleDataProviderChanged(); private: class ColumnPropertyInfo @@ -136,6 +141,7 @@ private: // key = column index // value = index (key) into mRoleNames QHash mDefaultDisplayRoles; + QJSValue mRoleDataProvider; }; QT_END_NAMESPACE -- cgit v1.2.3