QTableView没有显示任何内容

Question

I am trying to prototype a window with a QTableView . There isn't yet any database behind it, but there will be at some point. I can't get the tableview to show anything. I get a rectangle with white space. I've looked at the examples online and seem to be doing everything right, as far as I can tell.

I set up a QTableView object with the GUI builder and then added the following code immediately after the call to ui.setupUi(this);

// set up prototype table model to hold dummy data
QSqlTableModel * model = new QSqlTableModel(this);

model->setTable("Errors");
model->setEditStrategy(QSqlTableModel::OnManualSubmit);
model->select();

// set header names
model->setHeaderData(0, Qt::Horizontal, QObject::tr("Error Number"));
model->setHeaderData(1, Qt::Horizontal, QObject::tr("Message"));
model->setHeaderData(2, Qt::Horizontal, QObject::tr("Details"));

// insert a dummy record
{
  QSqlRecord record;
  QSqlField field1("Errno", QVariant::Int);
  field1.setValue(1);
  record.insert(0, field1);

  QSqlField field2("Msg", QVariant::String);
  field2.setValue(QString("Unable to perform snapshot"));
  record.insert(1, field2);

  QSqlField field3("Details", QVariant::String);
  field3.setValue(QString("Unable to perform snapshot. Please try again"));
  record.insert(2, field3);

  model->insertRecord(0, record);
}

// insert a dummy record
{
  QSqlRecord record;
  QSqlField field1("Errno", QVariant::Int);
  field1.setValue(1);
  record.insert(0, field1);

  QSqlField field2("Msg", QVariant::String);
  field2.setValue(QString("Unable to perform snapshot"));
  record.insert(1, field2);

  QSqlField field3("Details", QVariant::String);
  field3.setValue(QString("Unable to perform snapshot. Please try again"));
  record.insert(2, field3);

  model->insertRecord(1, record);
}

ui.errMsgsTableView->setEditTriggers(QAbstractItemView::NoEditTriggers);
ui.errMsgsTableView->setModel(model);

ui.errMsgsTableView->show();

Anyone have any suggestions? What am I missing?

Answer 1

You cannot use a QSqlTableModel without a database. As a quick workaround, you could connect it to a temporary in-memory sqlite table that literally can be created in two statements. For prototyping you should probably use a QStandardItemModel , though. Here's a complete example:

// https://github.com/KubaO/stackoverflown/tree/master/questions/dummymodel-37577922
#include <QtWidgets>

template <typename T> QStandardItem * newItem(const T val) {
  auto item = new QStandardItem;
  item->setData(val, Qt::DisplayRole);
  return item;
}

int main(int argc, char ** argv) {
   QApplication app{argc, argv};

   QStandardItemModel model;
   model.setColumnCount(3);
   model.setHorizontalHeaderLabels(QStringList{"Error Number", "Message", "Details"});

   auto newRow = []{ return QList<QStandardItem*>{
         newItem(1),
         newItem("Unable to perform snapshot"),
         newItem("Unable to perform snapshot. Please try again")};
   };
   model.appendRow(newRow());
   model.appendRow(newRow());

   QTableView view;
   view.setModel(&model);
   view.show();

   return app.exec();
}