被class修饰的计算类型属性,可以被子类重写 被static修饰的类型属性(存储、计算),不可以被子类重写 属性观察器: 可以在子类中为父类属性(除了只读计算属性、let属性)增加属性观察器 classCircle{varradius:Int=1}classSubCircle:Circle{overridevarradius:Int{willSet{print("SubCircle willSetRadius",newValue)}didSe...
static func sendData() { print("this is static method") } } class MovieService: Service { override class func fetchData() { print("this is movieService") } //error: Cannot override static method // override static func sendData() { // print("this is movieService") // } } 21.懒...
static method: UI content hugging and compression resistance : push/modal segues: auto resize mask: responder chain: autolayout: layer: table/collection View: table/collection view性能出问题: viewDidLayoutSubviews() - setNeedsDisplay() safeArea: frame/bounds: 一般开发 Protocol: 用协议...
When subclassing an Objective-C class and overriding its methods, or conforming to an Objective-C protocol, the type signatures of methods need to be updated when the parent method usesidin Objective-C. Some common examples are theNSObjectclass’sisEqual:method and theNSCopyingprotocol’scopyWith...
If a type initializer or factory method returns an implicitly unwrapped optional value then the redundantType rule may remove the explicit type in a situation where it's actually required. To work around this you can either use --redundanttype explicit, or use the // swiftformat:disable:next ...
我们知道Class extension使用的是Static dispatch: class MyClass { } extension MyClass { func extensionMethod() {} } class SubClass:MyClass { override func extensionMethod() {} } 以上代码会出现错误,提示Declarations in extensions can not be overridden yet。
Each of this method alter the receiver instance of the attributed string and also return the same instance in output (so chaining is allowed).Addadd(style: String, range: NSRange? = nil): add to existing style of string/substring a globally registered style with given name. add(styles: [...
Method Dispatch 我们之前在Static dispatch VS Dynamic dispatch中提到过,能够在编译期确定执行方法的方式叫做静态分派Static dispatch,无法在编译期确定,只能在运行时去确定执行方法的分派方式叫做动态分派Dynamic dispatch。 Static dispatch更快,而且静态分派可以进行内联等进一步的优化,使得执行更快速,性能更高。
而在Swift中,类属性的声明相当明了,相当于在类的{}里面的static属性就能直接通过 XXX.xx 来使用了,就很直观,所以我这里是直接把类属性当做是Swift中一个比较有意思的特性的。
If the object conforms to protocolXLFormOptionObject, XLForm gets the display value fromformDisplayTextmethod. Otherwise it return nil. That means you should conforms the protocol:). You may be interested in change the display text either by setting upnoValueDisplayTextorvalueTransformerproperty or ...