Autocomplete textbox

Wild Pointer

hi Qt community
i'm looking for the way of implementing dynamic QCompleter.
let me explain what i need
i have a phonebook table (in MySQL) with name,phoneNumbers columns and it contains about 30,000 records (so i can't simply use QCompleter with a QStringList or something like that).
so, i need a textbox that sends a query to the database (with textchanged signal for example) and probably a code that updates QCompleter with the query's result and shows the suggestions(like AJAX completers in the web).
example:
1.user type key "s" into the textbox.
2.a query "SELECT blablabla WHERE LIKE %".(only records starting with the s character)
3.textbox shows the suggestions.("stan","smith","steve","...")
4.done

and after all, my QLineEdit is in the custom ItemView table(with custom itemdelegate),so i can't use subclassed QLineEdit.

thanks

messi

Hi Wild Pointer,
the first part isn't that difficult.
QLineEdit generate a signal like textChanged().
This signal will be send to a second thread which will check for a new query of your database.
The response will the be send to the gui thread to actualize the QCompleter.
The word list is provided as a QAbstractItemModel which then can be used to update the QCompleter.

I hope this will help you.

Wild Pointer

thank you for your respond messi
i already have the complete QLineEdit+SQL autocompleter class.
the main problem is the QTableView with QItemDelegate.
when you use your custom QLineEdit class, the QTableView(or maybe QItemDelegate::createEditor) make your popup(or inline)completion buggy(small window will show & hide and that will not work at all).
did you tried QTableView+QItemDelegate+QLineEdit together ?

messi

Yes I used it. It can be difficult. Here is how I did it but with out completer:

//class TableDelegate is not necessary. You can use QStyledItemDelegate directly
@class TableDelegate : public QStyledItemDelegate
{
public:
TableDelegate( QWidget* parent = 0 ) : QStyledItemDelegate( parent ){}

protected:
virtual void paint( QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index ) const;

};@
//=====================================================================
@class EditFieldDelegate : public TableDelegate
{
Q_OBJECT
public:
EditFieldDelegate( QWidget* parent = 0 );
QWidget createEditor(QWidget parent, const QStyleOptionViewItem &option, const QModelIndex &index) const;
void setEditorData( QWidget editor, const QModelIndex& index ) const;
void setModelData( QWidget editor, QAbstractItemModel* model, const QModelIndex& index ) const;
void updateEditorGeometry( QWidget* editor, const QStyleOptionViewItem& option, const QModelIndex& index ) const;
type );

signals:
void editorClosing();
void selectionChanged( int row, int column ) const;
void textChanged(const QString& text);

private slots:
void editorIsClosing( QWidget * editor, QAbstractItemDelegate::EndEditHint hint );
};@
//===============================================================
@EditFieldDelegate::EditFieldDelegate( IDataClientManager* dataClientManager, const QString& connectName, bool mpDependent, QWidget* parent )
: TableDelegate( parent )--
{

}
@
//-----------------------------------------------------------------------------
@QWidget* EditFieldDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem&, const QModelIndex& index) const
{

QLineEdit* editor = new QLineEdit( parent );
editor->showLabel( false );

return editor;

}@

//-----------------------------------------------------------------------------
@void EditFieldDelegate::setEditorData( QWidget* editor, const QModelIndex& index ) const
{
editor->setFocus( Qt::OtherFocusReason );
QString data = index.model()->data( index, Qt::EditRole ).toString();
QLineEdit* field = qobject_cast<QLineEdit*>( editor );

if( field )
{
    field->setText( data );
}

}@

//-----------------------------------------------------------------------------
@void EditFieldDelegate::setModelData( QWidget* editor, QAbstractItemModel* model, const QModelIndex& index ) const
{
QLineEdit* field = qobject_cast<QLineEdit*>( editor );

if( field )
{
    model->setData( index, field->getLineEdit()->text(), Qt::EditRole );
}

}@

//-----------------------------------------------------------------------------
@void EditFieldDelegate::updateEditorGeometry( QWidget* editor, const QStyleOptionViewItem& option, const QModelIndex& ) const
{
editor->setGeometry( option.rect );
}@
//=============================================================
// In your code where you initialize the table you would need the folllowing:
@
......
EditFieldDelegate* editDelegate = new EditFieldDelegate( );
table->setItemDelegateForColumn( 2, editDelegate );
.......
connect( editDelegate, SIGNAL(textChanged(QString)), this, SLOT(updateTableItem()) );@