The answer in stackoverflow is correct.

Is there no other way to get notified when an Edit begins?

just declare and emit your custom signal in the delegate subclass

Remember 1 model can service multiple views so, normally, the model should not depend on the state of the view or delegate

@Kushan
Or you can use resizeColumnsToContents() method for the same.

You can use either QTreeWidget, QTableWidget, QTreeView+QStandardItemModel, QTableView+QStandardItemModel, QTreeView+QAbstactTableModel subclass, QTableView+QAbstactTableModel subclass for what you are trying to do.

I would go with a QT*View+QStandardItemModel (tree or table doesn't matter).

The functionalities you describe are:

only some columns will be editable

use QStandardItem::setFlag

Entering a value in the cents column (a logarithmic measure of frequency) will change the value in the hertz column, and vice versa

connect a slot to QStandardItemModel::dataChanged signal

There will be a button next to the table to add an additional note to the scale

connect a slot that calls QStandardItemModel::insertRows to the QPushButton::clicked signal

Так проверьте соединение при запуске.

И может, драйвер для SQLite собран только дебаговый? Надо и релизный тоже собрать.

@SGaist

Thank you for your clarification on the behaviour of QTableView.

Your description implies there should actually be 3 queries against the data, then. I only see 2. However, I admit I would need more time to be sure.

Let me see if I have understood the behaviour of setSortingEnabled() & sortByColumn():

setSortingEnabled() is what makes the View show sort indicators on column headers and allow clicking. It also executes a data fetch query, passing whatever (if anything) is currently defined as the sort order (from sortByColumn()) into an ORDER BY. sortByColumn() determines the ORDER BY. It too executes a data fetch.

(Please correct me if I am wrong.) Now, after (just, i.e. no sortByColumn() yet) a setSortingEnabled() I will see the sort indicator in some direction on some column. I am guessing this would be Ascending on column #0 initially(?) However, the query it issues has no ORDER BY at all, so by definition the rows are in indeterminate order. This seems simply inconsistent to me.

What I would have expected/hoped is that setSortingEnabled() would have passed an ORDER BY col0 ASC if that is how the data is supposed to be sorted to correspond to the initial sort indicator state, and/or an optional parameter to allow specification of the initial sort order desired in the View and to be passed in the initial query --- in effect, combining the setSortingEnabled() with an initial sortByColumn(). Or even, as you say, an equivalent of QSqlTableModel.setSort(). As it stands it seems you must fetch the data twice simply to correspond to the View's initial state.

I have inherited 32K lines of code which uses every kind of Qt SQL/model/view architecture all over the place, it's a mess. I will indeed investigate QSortFilterProxyModel. I don't mind which code I use to achieve it, I just don't expect any necessity to fetch the data multiple times for the initial situation.

Thanks everyone for answer.
I am end up with write my own models, the load time reduce to 3s for 30k row and 150 col each.

Put a QSortFilterProxy model in-between. then save from the proxy instead of the main model.

P.S.
connect(currentTableHeader, SIGNAL(sectionClicked(int)), this, SLOT(on_sectionClicked(int))); and void mainWidget::on_sectionClicked(int index) are useless. this is the default behaviour of QTableView, you don't have to implement it manually

Did you already checked the bug report system to see if there was something related ?

If not, please consider opening a new report providing a minimal compilable example showing the behaviour.

I may be wrong but you can use signal and slot (on changing textbox's text example):

//mainwindow.cpp constructor: MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { // connection for accessing to UI from another UI ProfileSearch* profilesearch = new ProfileSearch; connect( profilesearch, SIGNAL(updateUI1Signal(const QString)), this, SLOT(updateUI2TextSlot(const QString) ) ); // launch profilesearch form: profilesearch.exec(); } //mainwindow.h { public slots: void updateUI2TextSlot( const QString text ) {ui->MWtextEdit->setText(text);} // set new text in mainwindow form } //profilesearch.h signals: void updateUI1Signal(const QString text);

// row click event handler

void ProfileSearch::on_row_column_whatewer_clicked() { emit updateUI1Signal("Hello from ProfileSearch form to MainWindow form"); }

In 90% of the cases you can use QStandardItemModel instead of going through the minefield that is subclassing an abstract model.

My advice is just to use that "universal model" instead of a custom one. If you really, really want to customise it as performance of QStandardItemModel is a problem then make sure you run your model through the Model Test (needs just a couple of trivial fixes to work on Qt5) that will tell you if you did everything as you were supposed to or you fell in the countless pitfalls of model subclassing

Hi and welcome to devnet,

You can use a proxy model that adds the columns you want/need.

You can keep updating the DB content and trigger the GUI update at some known interval or when a certains amount of changed happened to the database.

@blastdoman You are correct, let's try this:

#include <QStyledItemDelegate> class DataChangeDelegate : public QStyledItemDelegate{ Q_OBJECT Q_DISABLE_COPY(DataChangeDelegate) public: enum{IsDirtyRole=Qt::UserRole + 44}; explicit DataChangeDelegate(QObject* parent=Q_NULLPTR) :QStyledItemDelegate(parent) {} virtual void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const Q_DECL_OVERRIDE{ const QVariant oldData = index.data(Qt::EditRole); QStyledItemDelegate::setModelData(editor,model,index); if(index.data(Qt::EditRole)!=oldData) model->setData(index,true,IsDirtyRole); } }; DataChangeDelegate* signalingDelegate=new DataChangeDelegate(this); connect(tableView->selectionModel(),&QItemSelectionModel::currentChanged,this,[this](const QModelIndex& idx)->void{ const int newRow= idx.isValid() ? idx.row():-1; if(newRow==currentRow) return; if(currentRow>=0){ const int maxCols =idx.model()->columnCount(idx.parent()); for(int i=0;i<maxCols ;++i){ if(idx.model()->index(currentRow,i,idx.parent()).data(DataChangeDelegate::IsDirtyRole).toBool()){ validateRow(currentRow); /* inside validateRow call something like: for(int i=0;i<model->columnCount();++i) model->setData(model->index(currentRow,i),QVariant(),DataChangeDelegate::IsDirtyRole); */ break; } } } currentRow=newRow; }); tableView->setItemDelegate(signalingDelegate);

this should return the list of the row indexes as sorted in the view. Hidden rows will be placed at the beginning

QList<int> viewIndexes(const QHeaderView* const view){ if(!view) return QList<int>(); const int numSections= view->count(); QMap<int,int> sorter; for(int i=0;i<numSections;++i) sorter.insert(view->sectionPosition(i),i); return sorter.values(); }

or alternatively:

QVector<int> viewIndexes(const QHeaderView* const view){ if(!view) return QVector<int>(); const int numSections=view->count(); QVector<int> result(numSections); for(int i=0;i<numSections;++i) result[i]=i; // Use stable_sort if you want the hidden sections still placed at the beginning but in the same order as the original model std::sort(result.begin(),result.end(),[view](int a,int b)->bool{return view->sectionPosition(a)<view->sectionPosition(b);}); return result; }

You'll have to benchmark them to tell which is more efficient

I've uncovered the same issue with QSqlQueryModel using the Windows QODBC database engine connected to MS SQL Server, and have been do some digging. Hopefully this will help others experiencing this issue.

There are a couple of different things happening here.

First, QSqlQueryModel does not support forward only queries. If you try to use a forward only query, QSqlQueryModel::lastError() will return "Forward-only queries cannot be used in a data model".

That seems clear, but does not explain the situation when the forward only is left in its default false state or explicitly set in code. During my exploration of the issue, I would notice that even though I called QSqlQuery::setForwardOnly(false), a call to QSqlQuery::isForwardOnly() made after the query was executed would show forward only set to true, something I did not understand.

Then I read the Qt documentation for setForwardOnly:

Setting forward only to false is a suggestion to the database engine, which has the final say on whether a result set is forward only or scrollable. isForwardOnly() will always return the correct status of the result set.

The database engine has the final say whether or not forward only is used!

Why was the database engine setting forward only? Qt's SQL Database Drivers documentation gives part of the answer if you know what you are looking at.

ODBC Stored Procedure Support

With Microsoft SQL Server the result set returned by a stored procedure that uses the return statement, or returns multiple result sets, will be accessible only if you set the query's forward only mode to forward using QSqlQuery::setForwardOnly().

By observation, the QODBC database engine (in Qt 5.8) recognizes when more than one return set has resulted from the query, so it is automatically setting forward only to true.

How are multiple result sets generated? I've uncovered a few ways.

A query that has multiple select statements (e.g. select * from table1; select * from table2). Stored Procedures In particular, MS SQL Server documentation has this to say:

SQL Server stored procedures have four mechanisms used to return data:

Each SELECT statement in the procedure generates a result set. The procedure can return data through output parameters. A cursor output parameter can pass back a Transact-SQL server cursor. The procedure can have an integer return code.

The first item in Microsoft's list was the key for me. When NOCOUNT is OFF, Even a simple internal variable assignment using a select (e.g. select @user = 'fred') generated a return set. Setting NOCOUNT to ON stops this behavior. From Microsoft's documentation on NOCOUNT

SET NOCOUNT ON prevents the sending of DONE_IN_PROC messages to the client for each statement in a stored procedure. For stored procedures that contain several statements that do not return much actual data, or for procedures that contain Transact-SQL loops, setting SET NOCOUNT to ON can provide a significant performance boost, because network traffic is greatly reduced.

The Solution for me turned out to be two things:

Add SET NOCOUNT ON to the top of my stored procedure so that only the select statement I cared about was returned Instead of using QSqlQueryModel, manually extract the results from the query and build my own QStandardItemModel.

@VRonin hey it works. I created a separate qt project and it's working there. I will see if I am doing something wrong in my project.

Actually the row to which I am trying to set a background color also has some color set to it in table widget stylesheet. Also tablewidget items also have a background color. I will check there. Thanks again.

Glad you found a solution !

Can you share a small sample code that triggers this behaviour ?

@IMAN4K said in change QSortFilterProxyModel behaviour for multiple column filtering:

Answer from stackfverflow : http://stackoverflow.com/questions/39488901/change-qsortfilterproxymodel-behaviour-for-multiple-column-filtering

This answer is the typical example that lead people to say

subclassing QSortFilterProxyModel, which would likely have a very limited reusability

It's bad. the proxy model implementation should not depend on the structure of the underlying data in sourceModel

@raven-worx: while I'm not sure it is the right solution for what @tokafr wants to do, he can take ownership of the vertical scrollbar and have some influence this way. I have done it before that way.

@tokafr: Instead of trying to influence the hidden layout of the QTableView, you could mask the space between the header view and the vertical scrollbar to make it look like it being part of the header view. Stylesheets are probably the best place to try.

Hi
Did you have a look at
http://doc.qt.io/qt-4.8/qitemeditorfactory.html#details

Seems to be such editor cache, like you have/want.

Hi again Vronin;

I improve little bit your idea. Perphaps is usefull for somebody.
As I comment before, my tableview will have diferent types of Aligment. Some columns goes to right, other left, other center.
But, I will use the same subclass created for QSqlQueryModel I will call this subclass many times in diferent part of my application.
I created something more variable, so at the moment that you call the subclass you must define by QStringList define in my subclass, for each column what kind of aligment you like.

Thanks Vronin for your help. And I share the code with you

================== MyQSqlQueryModel.h ======================
#ifndef MYQSQLQUERYMODEL_H
#define MYQSQLQUERYMODEL_H
#include <QSqlQueryModel>

#include <QObject>

class MyQSqlQueryModel : public QSqlQueryModel
{
public:
MyQSqlQueryModel();
QVariant data(const QModelIndex &item, int role) const;
QStringList AligmentDefinition; // HERE I DEFINE THE ALIGMENT BY COLUMNS
};

#endif // MYQSQLQUERYMODEL_H

================== MyQSqlQueryModel.cpp ======================
#include "myqsqlquerymodel.h"

MyQSqlQueryModel::MyQSqlQueryModel()
{

}

QVariant MyQSqlQueryModel::data(const QModelIndex &item, int role) const
{
if(role==Qt::TextAlignmentRole)
{
if(AligmentDefinition.size()==0)
{// There are any definition
return 0;
}
if(item.column() > AligmentDefinition.size())
{// There are no definition for that Column
return 0;
}
int i = item.column();
QString Value = AligmentDefinition.value(i);
if(Value =="1")
return int(Qt::AlignRight | Qt::AlignVCenter);
if(Value=="2")
return int(Qt::AlignCenter | Qt::AlignVCenter);
if(Value=="3")
return int(Qt::AlignLeft | Qt::AlignVCenter);
}
return QSqlQueryModel::data(item,role);
}

=============== MAIN PROGRAM =======================
MyQSqlQueryModel *model = new MyQSqlQueryModel;
model->setQuery("SELECT * FROM SPSSourceLines");
model->AligmentDefinition << "1" << "2" << "3";
QModelIndex index;
index = model->index(0,0);
model->data(index,7);

After much experimentation and some luck I found the solution to this mystery.

On startup I had

ui->tvRMA->horizontalHeader()->restoreState(...);

which restored invalid information from previous sessions with different layouts. Clearing the database of previous sessions brought back the proper behaviour.

Mike

@Nosba said:

but how can I know when the user is editing a cell?

I don't know, and that wasn't your original question. One thing you could try is to subclass the view and reimplement the edit() method from where you can emit a signal that notifies you when editing has started. I hope that helps.

Kind regards.

@raven-worx
Jackpot! Thank you so much for your help!! Finally I did it using QFileSystemWatcher.
Thumbs up for you (if possible?!). :)

Thread marked as solved.
Cheers

Sure. Thanks .

QTableWidget already has an internal model otherwise it's a QTableView.

@raven-worx

@raven-worx said:

do you really insert columns? or rows?
ANd do you call the signals with the correct indexes?

Well the columns are properly updated with the correct information after the beginInsertColumns and endInsertColumns, so yes I am 100% certain the view is being updated when the model changes. I'm also certain that the sort and delete work as both functions are reflective in the view.

yes it's not necessary to call dataChanged() with an invalid index. Rather you should call it with the index which data has cahnged obviously.

I understand that, again this code was not written by me, I'm simply attempting to solve an issue that was discovered. Moving on from both of your points we still have yet to find a solution. The issue is with the selection of data, not the addition, subtracting or sorting thereof. I believe the issue had to do with the Update function (as a hunch) perhaps it is a mutex locking issue in the model?

@alizadeh91
Either you paint it yourself since you already have the QModelIndex at hand:

QColor color = index.data( Qt::BackgroundColorRole ).toColor();

or by letting the style paint the stuff. Note that this also paints the selected background.

style->drawPrimitive( QStyle::PE_PanelItemViewItem, &option, painter, widget );

I think i've found a solution.

First, i install an eventFilter in my custom editor widget B on the internal spinbox :

internalSpinbox->installEventFilter(this);

Then, i implement eventFilter to treat the events on the spinbox and duplicate them to the parent:

bool AbstractRatioQuantitySpinbox::eventFilter(QObject *object, QEvent *event) { // cf http://stackoverflow.com/questions/12145522/why-pressing-of-tab-key-emits-only-qeventshortcutoverride-event if (event->type() == QEvent::KeyPress) { auto keyEvent = static_cast<QKeyEvent *>(event); if (keyEvent->key() == Qt::Key_Tab || keyEvent->key() == Qt::Key_Backtab) { QApplication::postEvent( this, new QKeyEvent(keyEvent->type(), keyEvent->key(), keyEvent->modifiers())); return true; } } else if (event->type() == QEvent::FocusOut) { auto focusEvent = static_cast<QFocusEvent *>(event); QApplication::postEvent(this, new QFocusEvent(focusEvent->type(), focusEvent->reason())); return false; } return QWidget::eventFilter(object, event); }

@Sudo007 said:

hi
I have created a class customDelegate (inherits QItemDelegate) in my Qt applicatrion and i created setEditor() function.But the delegate is not visible in the QTableView , untill i click on the row.
How to fix the issue?

How did you implement the paint() in your custom delegate ? As you are adding different widget in each cell, you need to paint a fake widget (QPushButton) using QApplication::style()->drawControl(QStyle::CE_PushButton, &btn,painter); where btn is QStyleOptionButton, then in createEditor() you create an instance of QPushButton.

@raven-worx
Hi,

thanks for your reply and information.
Will mark it as "solved", as it is only a minor but interesting styling "issue" :)

@tokafr
if i got you correct you want to drag&drop from your Qt application to the filesystem?
If so take a look here.

Można użyć modelu proxy, który będzie interpretował jakieś dane (np. "0" i "1") jako checkbox, np.

class MyProxy : public QIdentityProxyModel { public: MyProxy(QObject* parent) : QIdentityProxyModel(parent) {} QVariant data(const QModelIndex& index, int role) const override { if (role == Qt::CheckStateRole && index.column() == 0) { QString str_value = QIdentityProxyModel::data(index, Qt::DisplayRole).toString(); return (str_value == "1") ? Qt::Checked : Qt::Unchecked; } return QIdentityProxyModel::data(index, role); } bool setData(const QModelIndex& index, const QVariant& value, int role) override { if (role == Qt::CheckStateRole && index.column() == 0) { QString str_value = (value.toInt() == Qt::Checked) ? "1" : "0"; return QIdentityProxyModel::setData(index, str_value, Qt::EditRole); } else return QIdentityProxyModel::setData(index, value, role); } Qt::ItemFlags flags(const QModelIndex& index) const override { Qt::ItemFlags f = QIdentityProxyModel::flags(index); if (index.column() == 0) f |= Qt::ItemIsUserCheckable; return f; } };

oczywiście numer kolumny i dane rozpoznawane jako "zaznaczony" można sobie dostosować.
Takiego modelu można użyć potem tak:

QSqlTableModel* model = new QSqlTableModel(parent, database); MyProxy* proxy = new MyProxy(parent); proxy->setSourceModel(model); tableView->setModel(proxy);

@thEClaw
Well, since you were worried about how clean your solution was, I thought I should come up with a nastier hack: -): I'm storing the ints in my map as negative numbers and then I retrieve the "real" numbers in the model's data() method like this:

... if (item.column() == 2) { int fake = recordsMap.keys().at(item.row()); return abs(fake); } ...

At least everything works and displays fine now.

I fiddled a lot with visualIndex() and logicalIndex() but couldn't find a way to make this work, so I'm keeping this for the time being. Thanks anyway for your suggestion!

Further investigation into the issue has revealed that HiearchicalHeaderView re-implements the header views sections, and there is no relationship between the QHeaderView notion of sections, and the HiearchicalHeaderView notion of sections.

As a result, the following calls are available, but return incorrect data.

QHeaderView::count() returns 0
QHeaderView::sectionSize(int) returns 0
QHeaderView::logicalIndex(int) returns -1
etc...

The upshot of this is that there is a significant amount of work required in HierarchicalHeaderView in order to make in feature complete, and that the way it is currently implemented is not symbiotic with QHeaderView

That essentially leaves 2 questions.

Does an open source feature-complete hierarchical header view exist? Is there a way to easily implement hierarchical headers in a QHeaderView?

It could be something in the Qt Designer ui form I was using. I've found that if I start afresh with a new form rebuilding the ui from scratch, then the view in the new ui does get updated straight away as expected.

I still don't know precisely what was driving the problem, but this "workaround" will do as a solution.

@MhM93
You can use button in each row of QTableView as shown in this example.

Hi and welcome to devnet,

Something's not clear. Do you have anything that is shown at all ?

In your code excerpt there's nothing related to the handling of the row/column count for example. Also your QTableView doesn't belong to any layout so are you resizing it somewhere ?

OK here we go. All the files are in DropBox and should be available via:

https://www.dropbox.com/sh/7hzpv4k021k50y2/AACobsU7FpvbllB_56UUffP5a?dl=0

I have hardcoded a minimal data set which is accessed by clicking on the Load button - so as to keep the system as intended. No other buttons work.