How to Populate a QStandardItemModel - c++

Question

I'm a beginner at Qt and I'm struggling to populate a QStandardItemModel from an XML file.
I've tried the following and the entire project runs successfully but the QtableView does not display the data.
Here is my main.cpp:
void readXml(const QString& fileName) {
QFile file(fileName);
if(!file.open(QFile::ReadOnly | QFile::Text)) {
qDebug() << "Cannot read file" << file.errorString();
return;
}
StockItems* stockitems = new StockItems;
XmlStockItemsReader xmlReader(stockitems);
if(!xmlReader.read(&file))
qDebug() << "Parse error in file " << xmlReader.errorString();
else {
stockitems->print();
stockitems->populateStockModel();
}
}
int main(int argc, char* argv[]) {
QApplication app(argc, argv);
StockItems si;
//! Change this to match the path of your project
QString path = "C:\\unisa\\cos3711\\FIConcession";
readXml(path + "\\stockitems.xml");
si.show();
return app.exec();
}
In stockitems.cpp I have the following function:
void StockItems::populateStockModel() {
foreach(Item* item, m_items) {
QList<QStandardItem*> newRow;
QStandardItem *stockID = new QStandardItem(QString("%1").arg(item->stockID()));
QStandardItem *desc = new QStandardItem(QString("%2").arg(item->desc()));
QStandardItem *price = new QStandardItem(QString("%3").arg(item->price()));
newRow.append(stockID);
newRow.append(desc);
newRow.append(price);
stockModel->appendRow(newRow);
}
}
If I do some debugging I can see that the stockID, desc and prices are correctly read, so the problem must lie somewhere with updating the stockModel.
My main StockItems Constructor is as follows:
StockItems::StockItems(QWidget *parent) :
QDialog(parent),
ui(new Ui::StockItems)
{
ui->setupUi(this);
stockModel = new QStandardItemModel(0, 3);
// Set Model Headers
stockModel->setHeaderData(0, Qt::Horizontal, "Stock ID", Qt::DisplayRole);
stockModel->setHeaderData(1, Qt::Horizontal, "Description", Qt::DisplayRole);
stockModel->setHeaderData(2, Qt::Horizontal, "Price", Qt::DisplayRole);
// Link Model to Table View
ui->tvStock->setModel(stockModel);
}
I have an add button which contains the following onclick code which works as expected so I'm just not sure if I'm referencing the stockModel correctly.
QList<QStandardItem*> newRow;
QStandardItem* stockID = new QStandardItem(QString("%1").arg(ui->tbStockId->text()));
QStandardItem* desc = new QStandardItem(QString("%2").arg(ui->tbDesc->text()));
QStandardItem* price = new QStandardItem(QString("%3").arg(ui->sbPrice->text()));
newRow.append(stockID);
newRow.append(desc);
newRow.append(price);
stockModel->appendRow(newRow);
Finally I think this might help, my stockitems.h file:
class StockItems : public QDialog
{
Q_OBJECT
public:
explicit StockItems(QWidget *parent = 0);
~StockItems();
void populateStockModel();
void addItem(Item* item);
void print() const;
private slots:
void on_btnAdd_clicked();
void on_btnDelete_clicked();
private:
Ui::StockItems *ui;
QStandardItemModel *stockModel;
QList<Item*> m_items;
};
This is a lot and please let me know if I should provide anything else but I'm really lost as to how to populate this model correctly.
Thanks for any guidance!

Answer 1

Your readXml function does not populate the StockItems instance that you create in your main function, but a completely new StockItems instance that isn't used anywhere.
For example, instead of
StockItems* stockitems = new StockItems;
in your readXml function, let readXml take another StockItems argument, and use that:
void readXml(const QString& fileName, StockItems *stockItems) {
// do everything here as before, except for the
// StockItems* stockitems = new StockItems;
...
}
int main(int argc, char* argv[]) {
...
readXml(path + "\\stockitems.xml", &si);
si.show();
...
}