SharedInstance 实际上是什么?

问题描述

sharedInstance 实际上是什么?我的意思是有什么用途?

What is sharedInstance actually? I mean what is the usage?

目前我在 2 个不同的文件之间进行通信时遇到了一些问题.

Currently I'm having some problem in communicating between 2 different files.

这是我的问题:

我有 1 个文件调用 A.h/A.m 和另一个文件调用 B.h/B.m.A.h 需要访问 B.h 中的一些数据，所以....有什么方法可以实现我想要的吗?

I have 1 file call A.h/A.m and another file call B.h/B.m. A.h need to access some of the data in B.h, so .... is there any possible way I could achieve what I want?

只是想知道它是SharedInstance"吗?能解决我的问题吗?

Just wonder is it "SharedInstance" able to solve my problem?

推荐答案

sharedInstance 有多种用途.

sharedInstance could be used for several ways.

例如，您可以从静态上下文中访问对象.实际上，它用于支持单例模式的大多数方式.这意味着在整个程序代码中只使用该类的一个对象，完全只使用一个实例.

For example you can access an object from a static context. Actually it is used most ways for supporting the Singleton-pattern. That means that just one object of the class is used in your whole program code, just one instance at all.

界面可能如下所示:

@interface ARViewController
{
}
@property (nonatomic, retain) NSString *ARName;

+ (ARViewController *) sharedInstance;

实现ARViewController:

Implementation ARViewController:

@implementation ARViewController
static id _instance
@synthesize ARName;
...
- (id) init
{
    if (_instance == nil)
    {
        _instance = [[super allocWithZone:nil] init];
    }
    return _instance;
}

+ (ARViewController *) sharedInstance
{
    if (!_instance)
    {
        return [[ARViewController alloc] init];
    }
    return _instance;
}

要访问它，请在 CustomARFunction 类中使用以下代码:

And to access it, use the following in class CustomARFunction:

#import "ARViewController.h"

@implementation CustomARFunction.m

- (void) yourMethod
{
    [ARViewController sharedInstance].ARName = @"New Name";
}

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