Single-pass value of iOS value

In iOS apps, there are often values and variable sharing in different view and applications, and there are several ways to do this:

1.extern mode

2. Single-case mode

3.delegate mode

The singleton pattern, as the name implies, is only one instance, which ensures that a class has only one instance, and instantiates it itself and provides it to the system as a whole. It is often used to do application-level shared resource control. This mode is used very frequently, and through a singleton class, you can implement parameter passing between different view

#import <Foundation/Foundation.h> @interface session:nsobject@property (strong,nonatomic) NSString * singlevalue;//implementation of a single case method + (Session *) getinstance; @end

#import "Session.h" @implementation session//single-instance static Session *instance;//Singleton + (Session *) getinstance {    @ Synchronized (self) {        if (instance = = Nil) {            instance = [[Self alloc] init];                    }    }    return instance;} -(ID) init{    if (self = [super init]) {        self.singlevalue = [[NSString alloc] init];    }    return self;} @end

Then, in the case where you need to use a singleton class import, this singleton class

Session *session = [session getinstance];

Session.singlevalue = @ "Good magic!" ";

NSString *value = Session.singlevalue;

Single-pass value of iOS value