Swift -入門到跑路(1)

代碼出現 Declaration is only valid at file scope

出現錯誤的原因

class MyClass: NSObject { 
extension ViewController: UIScrollViewDelegateDelegate{
                   ... 
            }

正確的寫法

class MyClass: NSObject { 
                 ...
}
extension ViewController: UIScrollViewDelegateDelegate {    
                 ...
}