Details
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Bug
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Resolution: Duplicate
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P3: Somewhat important
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None
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4.3.1
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None
Description
It seems that to get a QDataWidgetMapper to work with a QSqlTableModel one has make sure it calls toFirst() (or setCurrentIndex) whenever the model selects( ) (which will happen without the programmer explicitly doing it).
Though this isn't too hard to do one could have expected this program to just work. Without uncommenting the emit selected() line only the first field is saved.
It seems to be because the internal QPersistentModelIndexes that the QDataWidgetMapper uses are invalidated. The delegate's setModelData function will be invoked with an invalid QModelIndex.
To reproduce:
start app
change the line edits to 123 and 456.
quit the application
restart the app
notice that 123 was saved but not 456.
#include <QtGui> class SqlTableModel : public QSqlTableModel { Q_OBJECT public: SqlTableModel(QWidget *parent = 0) : QSqlTableModel(parent) {} virtual bool select() { const bool ret = QSqlTableModel::select(); // emit selected(); // without this it doesn't work return ret; } signals: void selected(); }; class ItemDelegate : public QItemDelegate { public: ItemDelegate(QObject *parent = 0) : QItemDelegate(parent) { } virtual void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const { qDebug() << "setting" << editor->property("text").toString() << index; QItemDelegate::setModelData(editor, model, index); } }; class MainWindow : public QMainWindow { Q_OBJECT public: MainWindow(QWidget *parent = 0) : QMainWindow(parent) { QWidget *w = new QWidget(this); setCentralWidget(w); QVBoxLayout *l = new QVBoxLayout(w); QLineEdit *edit1 = new QLineEdit(w); QLineEdit *edit2 = new QLineEdit(w); l->addWidget(edit1); l->addWidget(edit2); QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE"); db.setDatabaseName("sample.db"); if (!db.open()) { Q_ASSERT(0); } QSqlQuery q(db); if (q.exec("CREATE TABLE fields (field1 VARCHAR(128), field2 VARCHAR(128));")) q.exec("INSERT INTO fields (field1, field2) VALUES ('aaaaa', 'bbbbb')"); SqlTableModel *model = new SqlTableModel(this); model->setTable("fields"); model->select(); model->setEditStrategy(QSqlTableModel::OnFieldChange); QDataWidgetMapper *mapper = new QDataWidgetMapper(this); connect(model, SIGNAL(selected()), mapper, SLOT(toFirst())); mapper->setModel(model); mapper->setSubmitPolicy(QDataWidgetMapper::AutoSubmit); mapper->setItemDelegate(new ItemDelegate(this)); mapper->addMapping(edit1, model->fieldIndex("field1")); mapper->addMapping(edit2, model->fieldIndex("field2")); mapper->toFirst(); } }; #include "main.moc" int main(int argc, char **argv) { QApplication app(argc, argv); MainWindow mw; mw.show(); return app.exec(); }