The protocol in Swift

Protocol :

The 1.Swift protocol is used to define the specifications that multiple types should follow

2. The agreement defines a specification that does not provide any implementation

3. The agreement unifies the attribute name , method, subscript , but the protocol does not provide any implementation

4. syntax format :

[ modifier ] Protocol protocol name : Parent Protocol 1, Parent agreement 2, ... {// protocol content }

Modifier : can be omitted , can also be private, internal, public one

The protocol name should have the same naming convention as the class name

A protocol can have multiple direct parent protocols , but the protocol only inherits the protocol and cannot inherit the class

Content of the Protocol : Specify the functions that the Protocol's implementation must provide, such as attributes , methods , constructors and subscripts, etc.

syntax to implement the protocol :

1.Struct struct name : First Protocol , Second protocol , ... {// implement protocol requirements }

2.Class class name : Superclass, First protocol, Second protocol , ... {// requirements for agreement }

protocol Specifies attribute requirements

1. syntax for defining attribute requirements in the protocol :

Class Var property name : type {get set}

Description : Class is optional , if there is a class keyword, the description is a type attribute , otherwise the instance property

You cannot replace class with Static

Get and set parts : just write get, set , No implementation required , set optional

Here is the Code section:

Viewcontroller.swift

Import Uikitclass Viewcontroller:uiviewcontroller, buttonviewdelegate {        //the properties specified in the agreement    var testvalueone:string = " Testvalueone "    var testvaluetwo:string =" Testvaluetwo "        var buttonview:buttonview!    Override Func Viewdidload ()    {        super.viewdidload ()                Self.buttonview = Buttonview.buttonview ()        Self.buttonView.frame = CGRectMake (0, 0, $, $)        Self.buttonView.center = Self.view.center        Self.buttonView.delegate = self        self.view.addSubview (self.buttonview)    }        //Mark-buttonviewdelegate        func Buttonview (Buttonview:buttonview, Didclickbutton Button:uibutton)    {        print ("Click the button inside the Buttonview")}    }

　　

Buttonview.swift (This class was created by Xib)

Import Uikitprotocol testdelegateone{    //define protocol properties    Var testvalueone:string {Get Set}}protocol testdelegatetwo{< c2/>//define the Protocol attribute    var testvaluetwo:string {Get Set}}//protocol can implement multiple inheritance protocol Buttonviewdelegate:testdelegateone, Testdele gatetwo{    //Protocol definition Method    func buttonview (Buttonview:buttonview, Didclickbutton Button:uibutton)}class Buttonview : uiview{    //define proxy object    var delegate:buttonviewdelegate?        Quick Create object Method    class Func Buttonview ()-Buttonview    {let        Buttonview:buttonview = Nsbundle.mainbundle () . loadnibnamed ("Buttonview", Owner:nil, Options:nil). First as! Buttonview        return Buttonview    }        @IBAction func buttonclick (Sender:uibutton)    {        if let Delegate = self.delegate {            Delegate.buttonview (self, Didclickbutton:sender)}}    

The protocol in Swift