iOS 检测网络状态 自动判断 认为提示网络改变

检测网络状态

在网络应用中，需要对用户设备的网络状态进行实时监控，目的是
让用户了解自己的网络状态，防止一些误会（比如怪应用无能）
根据用户的网络状态进行智能处理，节省用户流量，提高用户体验
WIFI\3G网络：自动下载高清图片
低速网络：只下载缩略图
没有网络：只显示离线的缓存数据

苹果官方提供了一个叫Reachability的示例程序，便于开发者检测网络状态
https://developer.apple.com/library/ios/samplecode/Reachability/Reachability.zip

Reachability的使用步骤
添加框架SystemConfiguration.framework

添加源代码

包含头文件

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1	<code class="hljs ruleslanguage">#import "Reachability.h"</code>

抽取工具类

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<code class="hljs objectivec">常见用法 // 是否WIFI + (BOOL) IsEnableWIFI {     return ([[Reachability reachabilityForLocalWiFi] currentReachabilityStatus] != NotReachable); }   // 是否3G + (BOOL) IsEnable3G {     return ([[Reachability reachabilityForInternetConnectionen] currentReachabilityStatus] != NotReachable); } </code>

网络监控

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<code class="hljs objectivec">[[NSNotificationCenter defaultCenter] addObserver:self  selector:@selector(reachabilityChanged:) name: kReachabilityChangedNotification object: nil]; self.netReachability = [Reachability reachabilityForInternetConnection]; [self.netReachability startNotifier];   - (void)dealloc {     [self.netReachability stopNotifier];     [[NSNotificationCenter defaultCenter] removeObserver:self name:kReachabilityChangedNotification object:nil]; } </code>

检测网络状态实例

NetWorkTool工具类

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<code class="hljs java">#import <foundation foundation.h="">   @interface NetworkTool : NSObject /**  *  是否WIFI  */ + (BOOL)isEnableWIFI;   /**  *  是否3G  */ + (BOOL)isEnable3G; @end </foundation></code>

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<code class="hljs objectivec">#import "NetWorkTool.h" #import "Reachability.h"   @implementation NetworkTool // 是否WIFI + (BOOL)isEnableWIFI {     return ([[Reachability reachabilityForLocalWiFi] currentReachabilityStatus] != NotReachable); }   // 是否3G + (BOOL)isEnable3G {     return ([[Reachability reachabilityForInternetConnection] currentReachabilityStatus] != NotReachable); } @end</code>

实现类

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<code class="hljs objectivec">#import "ViewController.h" #import "Reachability.h" #import "NetworkTool.h"   @interface ViewController () @property (nonatomic, strong) Reachability *reachability; @end   @implementation ViewController   - (void)viewDidLoad {     [super viewDidLoad];       // 监听网络状态发生改变的通知     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(networkStateChange) name:kReachabilityChangedNotification object:nil];       // 获得Reachability对象     self.reachability = [Reachability reachabilityForInternetConnection];     // 开始监控网络     [self.reachability startNotifier];   }   - (void)dealloc {     [self.reachability stopNotifier];     [[NSNotificationCenter defaultCenter] removeObserver:self]; }   - (void)networkStateChange {     NSLog(@"网络状态改变了");     [self checkNetworkState]; }   - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {     [self checkNetworkState]; }</code>

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<code class="hljs objectivec">#pragma mark - App应用程序网络类型改变就会调用 - (void)networkStateChange {     if ([NetWorkTool isEnableWIFI]) {         UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"温馨提示您" message:@"您现在网络环境为wifi！开始畅享吧！" delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];         [alert show];     } else if ([NetWorkTool isEnable3G]) {         UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"温馨提示您"  message:@"您现在网络环境为3G/4G网络！" delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];         [alert show];     } else {         UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"温馨提示您" message:@"您当前没有可连的网络或已经掉线！" delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];         [alert show];     }