QT :how to check if there Empty cell in qt table widget - qt

Question

i have table widget with specific row and column ,
my function is as follow
get value from the first column and second column
compare between them and return result in the third column
Ex: first column :1 2 3 Second column 2 2 3 Result column No Yes Yes
I make sure that my code work by using the qDebug, however when I compile and run it the mainwindow stopped and crash.
I use for loop to go throw all rows for(int row=0;rowtableWidget->rowCount();row++)
I think this line rowtableWidget->rowCount() coz when it read empty cells the app Freeze and stop working .
how can I void that to happen
void MainWindow::GenerateRes() {
QString Result;
for(int row = 0; row < ui->tableWidget->rowCount(); row++) {
QString R1 = ui->tableWidget->item(row, 0)->text();
QString R2 = ui->tableWidget->item(row, 1)->text();
if(R1 == R2) {
Result = "P" ;
} else {
Result = "F" ;
}
QTableWidgetItem *Item = new QTableWidgetItem(Result);
ui->tableWidget->setItem(row, 2, Item);
qDebug() << Item;
}
}

Answer 1

To check whether the cell(i,j) in QTableWidget is empty or not, use isNull() or isEmpty().
Example:
for(int i=0; i < ui->tableWidget->rowCount(); i++)
{
for(int j=0; j < ui->tableWidget->columnCount(); j++)
{
bool flag = ui->tableWidget->item(i,j)->text().isNull();
if (!flag) /* the cell is not empty */
{
// do stuff
}
else /* the cell is empty */
{
// do stuff
}
}
}

Answer 2

maybe you should check the values returned from tableWidget::item(), because the functions can return 0 if no item is asigned to the provided coordinates, and in that case you're trying to call a method (QTableWidgetItem::text()) on a zero pointer.
Try something like:
QString R1;
QTableWidgetItem *item1(ui->tableWidget->item(row,0));
if (item1) {
R1 = item1->text();
}
// and so on...
Your code looks strange anyway, the 5th line (ui->tableWidget->rowCount()) doesn't make sense, you shouldn't be able to compile that (at least you're missing a semicolon).