QStandardItemModel doesn't display data

[gabor53]

@mjsurette
I initialize the db when the program starts in main.cpp like this:

    QSqlDatabase db;
    QString fileQstring = "C:/Programming/Projects/FolkFriends_1_0/db.db";

    db = QSqlDatabase::addDatabase ("QSQLITE");
    db.setDatabaseName (fileQstring);
    qDebug() << "Connection Display created in main.cpp. ";

    bool OK = db.open ();

    if(OK == true)
        {
            qDebug() << "The db (MainWindow) is open!";
        }
    else
        {
            qDebug() << "The db (MainWindow) is not open!";
        }

    if(!db.open ())
        {
            qDebug() << "The database (db) is NOT open!" << db.lastError ();

        }

The connection works at other places.
Last error displays no error. I used the same Qt version (Qt 5.7) throughout the program.

[Pradeep Kumar]

Hi,

can u check few things,

1. Is db opened succesfully.
2. values are present in dB of the respective tables.
3. while retreiving provide qDebug() statements, so u can verify the data.
4. Check the table name which u have provided,is it correct?.

Thanks,

[Pradeep Kumar]

Construct the model and then add it to view.

[SGaist]

Hi,

You're trying to open your database twice which is wrong.

Did you check that you are indeed passing in your loop ? Note that your first test will never pass since row1 is initialized at 1.

[gabor53]

@Pradeep-Kumar
Hi,
It has data. I added

 qDebug() << "ID in fix: " << query_fix.value (0).toString ();

and I got the following:
ID in fix: "4"
ID in fix: "1"
ID in fix: "3"
ID in fix: "2"
which is exactly what supposed to be there. It just doesn't show up in the table.

[SGaist]

You don't set any column count. That's something you have to set either at construction time or before you start adding rows/data.

[Pradeep Kumar]

void FixDb::correctFriend()
{
qDebug() << "Entered correctFriend!";

QSqlQuery query_fix  ("SELECT * FROM Items ORDER BY NAME ASC ");

if(query_fix.isActive()==true)
    {
        qDebug() << "The query_fix is active.";
    }
else
    {
        qDebug() << "The query_fix is NOT active." << query_fix.lastError ();
    }



QStandardItemModel *fixmodel = new QStandardItemModel(this);
fixmodel->setHeaderData (0,Qt::Horizontal, QObject::tr("ID"));
fixmodel->setHeaderData (1,Qt::Horizontal, QObject::tr("Name"));
fixmodel->setHeaderData (2,Qt::Horizontal, QObject::tr("What is the Friend?"));
fixmodel->setHeaderData (3,Qt::Horizontal, QObject::tr("The Friend's Picture"));
fixmodel->setHeaderData (4,Qt::Horizontal, QObject::tr("Material"));
fixmodel->setHeaderData (5,Qt::Horizontal, QObject::tr("Color"));
fixmodel->setHeaderData (6,Qt::Horizontal, QObject::tr("Description"));
fixmodel->setHeaderData (7,Qt::Horizontal, QObject::tr("Adoption Date"));
fixmodel->setHeaderData (8,Qt::Horizontal, QObject::tr("Signed by"));
fixmodel->setHeaderData (9,Qt::Horizontal, QObject::tr("History"));
fixmodel->setHeaderData (10,Qt::Horizontal, QObject::tr("Age"));
fixmodel->setHeaderData (11,Qt::Horizontal, QObject::tr("Notes"));
fixmodel->setColumnCount(12);		// as per your column header its 11							
	
ui->tableView_fix->horizontalHeader ()->setStyleSheet ("QHeaderView{font: 14pt Arial; color: blue; font-weight: bold;}");
ui->tableView_fix->verticalHeader ()->setVisible (false);
ui->tableView_fix->setAlternatingRowColors (true);
ui->tableView_fix->setStyleSheet ("alternate-background-color: rgb(224,255,248); background-color: white; font: 14pt Arial");
ui->tableView_fix->setEditTriggers (QAbstractItemView::CurrentChanged);

ui->tableView_fix->setColumnWidth (0,100);
ui->tableView_fix->setColumnWidth (1,200);
ui->tableView_fix->setColumnWidth (2,200);
ui->tableView_fix->setColumnWidth (3,90);
ui->tableView_fix->setColumnWidth (4,200);
ui->tableView_fix->setColumnWidth (5,200);
ui->tableView_fix->setColumnWidth (6,350);
ui->tableView_fix->setColumnWidth (7,200);
ui->tableView_fix->setColumnWidth (8,200);
ui->tableView_fix->setColumnWidth (9,350);
ui->tableView_fix->setColumnWidth (10,200);
ui->tableView_fix->setColumnWidth (11,350);
ui->tableView_fix->setWordWrap (true);


for(int row1 = 0; query_fix.next(); ++row1)
    {
 fixmodel->setRowCount(row1);
 fixmodel->setData (fixmodel->index(row1,0),query_fix.value (0).toString());			// oth column value
 fixmodel->setData (fixmodel->index(row1,1),query_fix.value (1).toString ());			// 1th column value	
fixmodel->setData (fixmodel->index(row1,2),query_fix.value (13).toString ());			// 13th column value

 fixPixmap.loadFromData (query_fix.value (2).toByteArray ());					// 2th column value	
 fixPixmap = fixPixmap.scaled (100,100,Qt::KeepAspectRatio);

 fixmodel->setData (fixmodel->index (row1,3),fixPixmap,Qt::DecorationRole);
fixmodel->setData (fixmodel->index(row1,4),query_fix.value (11).toString ());			// 11th column value	
fixmodel->setData (fixmodel->index(row1,5),query_fix.value (10).toString ());			// 10th column value	
 fixmodel->setData (fixmodel->index(row1,6),query_fix.value (3).toString ());			// 3th column value

        monthf = query_fix.value (4).toString ();								// 4th column value
        dayf = query_fix.value (5).toString ();								// 5th column value	
        yearf = query_fix.value (6).toString ();								// 6th column value
        date = monthf + "/" + dayf + "/" + yearf;	

fixmodel->setData (fixmodel->index(row1,5),date);
fixmodel->setData (fixmodel->index(row1,6),query_fix.value (12).toString ());			// 12th column value
fixmodel->setData (fixmodel->index(row1,7),query_fix.value (7).toString ());			// 7th column value
fixmodel->setData (fixmodel->index(row1,8),query_fix.value (8).toString ());			// 8th column value	
fixmodel->setData (fixmodel->index(row1,9),query_fix.value (9).toString ());			// 9th column value

 ui->tableView_fix->setRowHeight (row1,100);
    }


ui->tableView_fix->setModel (fixmodel);

}

[Pradeep Kumar]

As @SGaist said u need to specify Columncount and rowcount.

fixmodel->setData (fixmodel->index(row1,5),query_fix.value (10).toString ());

fixmodel->setData (fixmodel->index(row1,5),date);

Are u trying to insert different values in same column?.

[VRonin]

EDIT, sorry, this is a duplicate of @SGaist 's answer

you are never adding the columns...

for(int row1 = 1; query_fix.next (); row1++)
        {
            if(row1 == 0)

row1 is never 0

[gabor53]

@VRonin
Hi,
I rewrote a few things. As a result it displays data:

void FixDb::correctFriend()
{
    qDebug() << "Entered correctFriend!";

    QSqlQuery query_fix  ("SELECT * FROM Items ORDER BY NAME ASC ");

    if(query_fix.isActive()==true)
        {
            qDebug() << "The query_fix is active.";
        }
    else
        {
            qDebug() << "The query_fix is NOT active." << query_fix.lastError ();
        }

    QStandardItemModel *fixmodel = new QStandardItemModel(this);


    const QSqlRecord qR = query_fix.record ();
    qDebug() << "The number of records: " << qR;
    fixmodel->insertColumns (0, qR.count());

    for(int row1 = 0; query_fix.next (); row1++)
        {
            fixmodel->insertRow (row1);
            fixmodel->setData (fixmodel->index(row1,0),query_fix.value (0).toString ());
            fixmodel->setData (fixmodel->index(row1,1),query_fix.value (1).toString ());
            fixmodel->setData (fixmodel->index(row1,2),query_fix.value (13).toString ());

            qDebug() << "ID in fix: " << query_fix.value (0).toString ();

            fixPixmap.loadFromData (query_fix.value (2).toByteArray ());
            fixPixmap = fixPixmap.scaled (100,100,Qt::KeepAspectRatio);

            fixmodel->setData (fixmodel->index (row1,3),fixPixmap,Qt::DecorationRole);
            fixmodel->setData (fixmodel->index(row1,4),query_fix.value (11).toString ());
            fixmodel->setData (fixmodel->index(row1,5),query_fix.value (10).toString ());
            fixmodel->setData (fixmodel->index(row1,6),query_fix.value (3).toString ());

            monthf = query_fix.value (4).toString ();
            dayf = query_fix.value (5).toString ();
            yearf = query_fix.value (6).toString ();
            date = monthf + "/" + dayf + "/" + yearf;

            fixmodel->setData (fixmodel->index(row1,7),date);
            fixmodel->setData (fixmodel->index(row1,8),query_fix.value (12).toString ());
            fixmodel->setData (fixmodel->index(row1,9),query_fix.value (7).toString ());
            fixmodel->setData (fixmodel->index(row1,10),query_fix.value (8).toString ());
            fixmodel->setData (fixmodel->index(row1,11),query_fix.value (9).toString ());
            ui->tableView_fix->setRowHeight (row1,100);

            ui->tableView_fix->horizontalHeader ()->setStyleSheet ("QHeaderView{font: 14pt Arial; color: blue; font-weight: bold;text-decoration: underline;}");
            ui->tableView_fix->verticalHeader ()->setVisible (false);
            ui->tableView_fix->setAlternatingRowColors (true);
            ui->tableView_fix->setStyleSheet ("alternate-background-color: rgb(224,255,248); background-color: white; font: 14pt Arial");
            ui->tableView_fix->setEditTriggers (QAbstractItemView::CurrentChanged);
            fixmodel->setHeaderData (0,Qt::Horizontal, QObject::tr("ID"));
            fixmodel->setHeaderData (1,Qt::Horizontal, QObject::tr("Name"));
            fixmodel->setHeaderData (2,Qt::Horizontal, QObject::tr("What is the Friend?"));
            fixmodel->setHeaderData (3,Qt::Horizontal, QObject::tr("Picture"));
            fixmodel->setHeaderData (4,Qt::Horizontal, QObject::tr("Material"));
            fixmodel->setHeaderData (5,Qt::Horizontal, QObject::tr("Color"));
            fixmodel->setHeaderData (6,Qt::Horizontal, QObject::tr("Description"));
            fixmodel->setHeaderData (7,Qt::Horizontal, QObject::tr("Adoption Date"));
            fixmodel->setHeaderData (8,Qt::Horizontal, QObject::tr("Signed by"));
            fixmodel->setHeaderData (9,Qt::Horizontal, QObject::tr("History"));
            fixmodel->setHeaderData (10,Qt::Horizontal, QObject::tr("Age"));
            fixmodel->setHeaderData (11,Qt::Horizontal, QObject::tr("Notes"));

            ui->tableView_fix->setColumnWidth (0,1);
            ui->tableView_fix->setColumnWidth (1,200);
            ui->tableView_fix->setColumnWidth (2,200);
            ui->tableView_fix->setColumnWidth (3,90);
            ui->tableView_fix->setColumnWidth (4,200);
            ui->tableView_fix->setColumnWidth (5,200);
            ui->tableView_fix->setColumnWidth (6,350);
            ui->tableView_fix->setColumnWidth (7,200);
            ui->tableView_fix->setColumnWidth (8,200);
            ui->tableView_fix->setColumnWidth (9,350);
            ui->tableView_fix->setColumnWidth (10,200);
            ui->tableView_fix->setColumnWidth (11,350);

            ui->tableView_fix->setWordWrap (true);

            ui->tableView_fix->setModel (fixmodel);
        }
}

The only problems I found:
1.) The first row's height is much less than the rest of the rows.
2.) The ID column is completely missing.
Is this the model's issue or i cut the first column off somewhere?
Thank you for all your help.

[VRonin]

fixmodel->setData (fixmodel->index(row1,0),query_fix.value (0).toString ());

don't call toString, setdata wants a QVariant, no need to convert anything

The problems you mentioned look a lot like view issues rather than model issues? are you using a custom view or delegate?

this

monthf = query_fix.value (4).toString ();
            dayf = query_fix.value (5).toString ();
            yearf = query_fix.value (6).toString ();
            date = monthf + "/" + dayf + "/" + yearf;
fixmodel->setData (fixmodel->index(row1,7),date);

is bad on so many levels.

use

fixmodel->setData (fixmodel->index(row1,7),QDate(query_fix.value (6).toInt(),query_fix.value (4).toInt(),query_fix.value (5).toInt());

[gabor53]

@VRonin said in QStandardItemModel doesn't display data:

fixmodel->setData (fixmodel->index(row1,7),QDate(query_fix.value (6).toInt(),query_fix.value (4).toInt(),query_fix.value (5).toInt());

I did the changes you recommended. The change is that in the Name column in the first row I have the ID. If I click on anywhere on the table, the ID from the first row disappears, replaced by the Name and the ID columns is still completely missing.

[gabor53]

@VRonin
As it looks It displays the database from column 2.

[VRonin]

do you have any events linked to selection or click?

[gabor53]

@VRonin

No. Or at least not yet.

[gabor53]

@VRonin
The following code displays the ID column:

void FixDb::correctFriend()
{
    qDebug() << "Entered correctFriend!";

    QSqlQuery query_fix  ("SELECT ID FROM Items ORDER BY NAME ASC ");

    if(query_fix.isActive()==true)
        {
            qDebug() << "The query_fix is active.";
        }
    else
        {
            qDebug() << "The query_fix is NOT active." << query_fix.lastError ();
        }

    while(query_fix.next ())
        {
            QString tempID = query_fix.value (0).toString ();
            qDebug() << "TempID: " << tempID;
        }

    QStandardItemModel *fixmodel = new QStandardItemModel(this);
    ui->tableView_fix->setModel (fixmodel);

    const QSqlRecord qR = query_fix.record ();
    qDebug() << "The number of records: " << qR;
    fixmodel->insertColumns (0,qR.count ());

    for(int row1 = 0; query_fix.next (); row1++)
        {
            fixmodel->insertRow (row1);
        }

    ui->tableView_fix->horizontalHeader ()->setStyleSheet ("QHeaderView{font: 14pt Arial; color: blue; font-weight: bold;text-decoration: underline;}");
    ui->tableView_fix->setAlternatingRowColors (true);
    ui->tableView_fix->setStyleSheet ("alternate-background-color: rgb(224,255,248); background-color: white; font: 14pt Arial");

    fixmodel->setHeaderData (0,Qt::Horizontal, QObject::tr("ID"));

    ui->tableView_fix->setColumnWidth (0,100);
}

but when I add

 fixmodel->setData (fixmodel->index(row1,0),query_fix.value (0));

after insertRow the column header disappears and the tableview is empty.

[VRonin]

I have a strong suspect the problem lies in the view, could you try the code below and see if the column is displayed correctly?

void FixDb::correctFriend()
{
    qDebug() << "Entered correctFriend!";

    QSqlQuery query_fix  ("SELECT ID FROM Items ORDER BY NAME ASC ");

    if(query_fix.isActive()==true)
        {
            qDebug() << "The query_fix is active.";
        }
    else
        {
            qDebug() << "The query_fix is NOT active." << query_fix.lastError ();
        }

    while(query_fix.next ())
        {
            QString tempID = query_fix.value (0).toString ();
            qDebug() << "TempID: " << tempID;
        }

    QStandardItemModel *fixmodel = new QStandardItemModel(this);
QTableView* tempView=new QTableView;
tempView->setAttribute( Qt::WA_DeleteOnClose ); // To prevent memory leak
    tempView->setModel (fixmodel);

    const QSqlRecord qR = query_fix.record ();
    qDebug() << "The number of records: " << qR;
    fixmodel->insertColumns (0,qR.count ());

    for(int row1 = 0; query_fix.next (); row1++)
        {
            fixmodel->insertRow (row1);
fixmodel->setData (fixmodel->index(row1,0),query_fix.value (0));
        }

   

    fixmodel->setHeaderData (0,Qt::Horizontal, QObject::tr("ID"));

    tempView->show();
}

[gabor53]

@VRonin
It displays only the original tableview from the ui. I can't see tempView .

[gabor53]

@VRonin
I figured it out, but the new table shows only the header row with the title ID.

[VRonin]

could you qDebug() << "Rows: " << fixmodel->rowCount() << " Columns: " << fixmodel->columnCount() just before tempView->show();?