UITableView in Swift

Question

I\'m struggling to figure out what\'s wrong with this code snippet. This is currently working in Objective-C, but in Swift this just crashes on the first line of the method.

Answer 1

Using "as" keyword would do the following two steps:
1.creating a optional value which wrap a variable of UITableViewCell;
2.unwrapping the optional value.

So,by doing this

var cell : UITableViewCell = tableView.dequeueReusableCellWithIdentifier("Component") as UITableViewCell

you would get a "plain" UITableViewCell type variable: cell.Theoretically speaking, it's ok to do this.But the next line

if (cell == nil) {}

makes trouble, because in swift, only the optional value can be assigned with nil.

So, to solve this problem, you have to make cell a variable of Optional type. just like this:

var cell = tableView.dequeueReusableCellWithIdentifier("Component") as? UITableViewCell

using the keyword "as?" would create a Optional variable, and this, undoubtedly, can be assigned with nil.