struct Weather{
var city :String?
var temp :String?
var weather :String?
}
class ViewController: UIViewController {
@IBOutlet weak var labelWeather: UILabel!
@IBOutlet weak var labelCity: UILabel!
@IBOutlet weak var labelTemp: UILabel!
var weatherData :Weather?{
didSet{
confView()
}
}
func confView(){
labelCity.text = self.weatherData?.city
}
}
I'm a swift beginner. The function named confView( ) is called by weatherData before the declaration statement. Is it right? The xCode didn't report an error. But i think "func confView()"should be placed before "var weatherData". Is it necessary?
No, that is not necessary (hopefully).
struct Weather{
var city :String?
var temp :String?
var weather :String?
}
class ViewController: UIViewController {
@IBOutlet weak var labelWeather: UILabel!
@IBOutlet weak var labelCity: UILabel!
@IBOutlet weak var labelTemp: UILabel!
var weatherData :Weather?{
didSet{
confView()
}
}
func confView(){
labelCity.text = self.weatherData?.city
}
}Somehow, it works like this (may be different, with multi pass of compiler, but that's essentially the mechanisms)
- The compiler reads the code, keep track of all declared calls to func, like line 13.
- Then, when it meets the declaration line 17, it completes the missing information.
Note that would be different in playground, which is not compiled, but somehow interpreted (with optimization).
