致命错误：在Tableview中展开Optional值时意外发现nil

Question

I had implemented UITableView with custom cell.It works fine.

Tableviewcell have 3 textfields in every cell.

I try to access all cell on submit button.

But app is crash due to access non-visible cell.

How can I got all cell's all 3 textfield values even they are not visible.

Thank you,

Answer 1

UITableView 's cellForRowAtIndexPath method will return nil if cell not visible. You should check for this, and perform only data source changes if so:

if let cell_note = self.tbl.cellForRowAtIndexPath(NSIndexPath(forRow: 0, inSection: 4)) as? NotesCell
{
    // do something with your data source
    // do something with cell_note that already loaded on screen
}
else
{
    // do something with your data source
    // your cell didn't loaded yet
    // you should only prepare fresh information in your data source for delegate method tableView(_:cellForRowAtIndexPath:) 
}

Note that if you have same data source changes for both cases (as usual in fact), you need move them out of this check