Item in QTableWidget

Vidhya

how can i check the item in the Qtablewidget having value or not

giesbert

What exactly do you mean by this?
AFAIK there is a method to get a pointer to an item, then you can query the values of the item. Does that help you?

Vidhya

@for (int row=0 ; row < ui->widget->rowCount();row++)
{
qDebug()<<"Ckeck point X "<<row;
QTableWidgetItem *item_test = ui->widget->item(row, 0);
if(!item_test->text().isEmpty())
{
check_count++;
qDebug()<<"Checkpoint y "<<row;
}
c++;
}
qDebug()<<"Check Count"<<check_count;@

for first loop(row=0) its working but in the next loop(row=1) it displays Ckeck point X 1;then the program is terminated

pls help me to fix this problem

andre

Always check if a pointer you get back from a method call that returns one is valid before dereferencing it. You are using item_test without checking if it is valid in line 5.

Vidhya

sorry i didn't catch your point.
Can u pls explain in detail.

andre

Take a look at these lines:
@
QTableWidgetItem *item_test = ui->widget->item(row, 0);
if(!item_test->text().isEmpty())
@

What happens if line 1 above sets item_test to 0? In line 2 you dereference the pointer, but you have no idea if the pointer is valid or not. So, do this instead:

@
QTableWidgetItem *item_test = ui->widget->item(row, 0);
if(item_test) {
if(!item_test->text().isEmpty()) {
@

Though you could combine that to:
@
QTableWidgetItem *item_test = ui->widget->item(row, 0);
if(item_test && !item_test->text().isEmpty())
@

Dereferencing a 0 (or an otherwise invalid) pointer will lead you into "undefined behaviour", usually leading to a crash or worse. Using either *the_pointer. or the_pointer-> is called dereferencing the pointer. That is: not trying to use the pointer as such, but the thing it points to. If the thing it points to is invalid, that will go wrong.

Vidhya

Thank U ,