- class Obserber {
- var name:String?
- var count:Int = 0
- {
- willSet{
- print("Will set an new value \(newValue) to count,current count is \(count)")
- }
- didSet{
- print("count changed form \(oldValue) to \(count)")
- if count < 10
- {
- name = "name1"
- }else
- {
- name = "name2"
- }
- }
- }
- }
- var ob:Obserber = Obserber()
- ob.count = 15
输出结果为:
Will set an new value 15 to count,current count is 0
count changed form 0 to 15