Swift single-instance mode implementation and class method

Let's talk about the class method before we start the singleton mode. The singleton mode needs to rely on the class method to implement

First, we know that the class method is called directly using the class name, without having to build the object and then call it.

In fact, the generation of the class method is very simple, only need to give our previous object method with the class keyword to decorate can

Let's look at an example

Object methods

    Func userName ()->string{        return "Zhangsan"    }

Class method

    Class Func UserName ()->string{        return "Zhangsan"    }

Let's start with a singleton pattern.

First, the singleton mode is generally used for data sharing, which saves resources when it is used without creating multiple objects. For example, the nsuserdefault of our attributes is a singleton

Next we implement a class that is used to share data. Named Mytool

Implemented as follows

Class mytool{    var currentnum:int=1    struct Toolp {        static var mytool:mytool?=nil    }    class Func Sharemytool ()->mytool {        if (Toolp.mytool = = nil) {            toolp.mytool=mytool ()        }        return toolp.mytool!    }    }

Use the following

        var mytool=mytool.sharemytool ()        mytool.currentnum=10        var mytool1=mytool.sharemytool ()        println ( Mytool1.currentnum)

We first create an object Mytool change the variable currentnum in the class to 10

And then we're going to print out the object (actually, the object we created last time) and find out that he's just 10 currentnum.

Okay, just a little bit easier, we can continue to play on their own, there are problems can be added group discussion

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Swift single-instance mode implementation and class method