iOS中使用 Reachability 检测网络

如果你想在iOS程序中提供一仅在wifi网络下使用(Reeder)，或者在没有网络状态下提供离线模式(Evernote)。那么你会使用到Reachability来实现网络检测。

写本文的目的

了解Reachability都能做什么

检测3中网络环境

2G/3G

wifi

无网络

如何使用通知

单个controller

多个controller

简单的功能:

仅在wifi下使用

Reachability简介

Reachablity 是一个iOS下检测,iOS设备网络环境用的库。

监视目标网络是否可用

监视当前网络的连接方式

监测连接方式的变更

苹果官方提供的Doc

http://developer.apple.com/library/ios/#samplecode/Reachability/Introduction/Intro.html

Github上的文档

https://github.com/tonymillion/Reachability

安装

创建 network 工程（network是我创建的demo工程，附件中可以下载到）

使用Cocoaspod安装依赖

在项目中添加 SystemConfiguration.framework 库

由于Reachability非常常用。直接将其加入到Supporting Files/networ-Prefix.pch中:

C代码







#import <Reachability/Reachability.h>

#import <Reachability/Reachability.h>

如果你还不知道cocoaspod是什么,看这里:

/article/3940783.html

使用

stackoverflow上有一篇回答，很好的解释了reachability的用法

http://stackoverflow.com/questions/11177066/how-to-use-ios-reachability

一般情况一个Reachability实例就ok了。

一个Controller只需要一个Reachability

Block方式使用

C代码







- (void)viewDidLoad

{

[super viewDidLoad];

DLog(@"开启 www.apple.com 的网络检测");

Reachability* reach = [Reachability reachabilityWithHostname:@"www.apple.com"];

DLog(@"-- current status: %@", reach.currentReachabilityString);

// start the notifier which will cause the reachability object to retain itself!

[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(reachabilityChanged:)

name:kReachabilityChangedNotification

object:nil];

reach.reachableBlock = ^(Reachability * reachability)

{

dispatch_async(dispatch_get_main_queue(), ^{

self.blockLabel.text = @"网络可用";

self.blockLabel.backgroundColor = [UIColor greenColor];

});

};

reach.unreachableBlock = ^(Reachability * reachability)

{

dispatch_async(dispatch_get_main_queue(), ^{

self.blockLabel.text = @"网络不可用";

self.blockLabel.backgroundColor = [UIColor redColor];

});

};

[reach startNotifier];

}

- (void)viewDidLoad
{
[super viewDidLoad];
DLog(@"开启 www.apple.com 的网络检测");
Reachability* reach = [Reachability reachabilityWithHostname:@"www.apple.com"];
DLog(@"-- current status: %@", reach.currentReachabilityString);

// start the notifier which will cause the reachability object to retain itself!

[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(reachabilityChanged:)
name:kReachabilityChangedNotification
object:nil];

reach.reachableBlock = ^(Reachability * reachability)
{
dispatch_async(dispatch_get_main_queue(), ^{
self.blockLabel.text = @"网络可用";
self.blockLabel.backgroundColor = [UIColor greenColor];
});
};

reach.unreachableBlock = ^(Reachability * reachability)
{
dispatch_async(dispatch_get_main_queue(), ^{
self.blockLabel.text = @"网络不可用";
self.blockLabel.backgroundColor = [UIColor redColor];
});
};

[reach startNotifier];
}

使用notification的方式

C代码







- (void)viewDidLoad

{

[super viewDidLoad];

DLog(@"开启 www.apple.com 的网络检测");

Reachability* reach = [Reachability reachabilityWithHostname:@"www.apple.com"];

DLog(@"-- current status: %@", reach.currentReachabilityString);

// start the notifier which will cause the reachability object to retain itself!

[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(reachabilityChanged:)

name:kReachabilityChangedNotification

object:nil];

[reach startNotifier];

}

- (void) reachabilityChanged: (NSNotification*)note {

Reachability * reach = [note object];

if(![reach isReachable])

{

self.notificationLabel.text = @"网络不可用";

self.notificationLabel.backgroundColor = [UIColor redColor];

self.wifiOnlyLabel.backgroundColor = [UIColor redColor];

self.wwanOnlyLabel.backgroundColor = [UIColor redColor];

return;

}

self.notificationLabel.text = @"网络可用";

self.notificationLabel.backgroundColor = [UIColor greenColor];

if (reach.isReachableViaWiFi) {

self.wifiOnlyLabel.backgroundColor = [UIColor greenColor];

self.wifiOnlyLabel.text = @"当前通过wifi连接";

} else {

self.wifiOnlyLabel.backgroundColor = [UIColor redColor];

self.wifiOnlyLabel.text = @"wifi未开启，不能用";

}

if (reach.isReachableViaWWAN) {

self.wwanOnlyLabel.backgroundColor = [UIColor greenColor];

self.wwanOnlyLabel.text = @"当前通过2g or 3g连接";

} else {

self.wwanOnlyLabel.backgroundColor = [UIColor redColor];

self.wwanOnlyLabel.text = @"2g or 3g网络未使用";

}

}

- (void)viewDidLoad
{
[super viewDidLoad];
DLog(@"开启 www.apple.com 的网络检测");
Reachability* reach = [Reachability reachabilityWithHostname:@"www.apple.com"];
DLog(@"-- current status: %@", reach.currentReachabilityString);

// start the notifier which will cause the reachability object to retain itself!

[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(reachabilityChanged:)
name:kReachabilityChangedNotification
object:nil];
[reach startNotifier];
}

- (void) reachabilityChanged: (NSNotification*)note {
Reachability * reach = [note object];

if(![reach isReachable])
{
self.notificationLabel.text = @"网络不可用";
self.notificationLabel.backgroundColor = [UIColor redColor];
self.wifiOnlyLabel.backgroundColor = [UIColor redColor];
self.wwanOnlyLabel.backgroundColor = [UIColor redColor];
return;
}

self.notificationLabel.text = @"网络可用";
self.notificationLabel.backgroundColor = [UIColor greenColor];

if (reach.isReachableViaWiFi) {
self.wifiOnlyLabel.backgroundColor = [UIColor greenColor];
self.wifiOnlyLabel.text = @"当前通过wifi连接";
} else {
self.wifiOnlyLabel.backgroundColor = [UIColor redColor];
self.wifiOnlyLabel.text = @"wifi未开启，不能用";
}

if (reach.isReachableViaWWAN) {
self.wwanOnlyLabel.backgroundColor = [UIColor greenColor];
self.wwanOnlyLabel.text = @"当前通过2g or 3g连接";
} else {
self.wwanOnlyLabel.backgroundColor = [UIColor redColor];
self.wwanOnlyLabel.text = @"2g or 3g网络未使用";
}
}

附件demo说明

开启wifi状态

关闭wifi的状态

遗留问题

如何在多个controller之前共用一个Reachability(附件demo中是一个controller一个Reachability实例)

应该在什么使用停止Reachability的检测.