IOS疯狂基础之网络检测

Reachability.h中定义了三种网络状态：

typedef enum {

NotReachable = 0, //无连接

ReachableViaWiFi, //使用3G/GPRS网络

ReachableViaWWAN //使用WiFi网络

} NetworkStatus;

因此可以这样检查网络状态：

Reachability *r = [Reachability reachabilityWithHostName:@“www.apple.com”];

switch ([r currentReachabilityStatus]) {

case NotReachable:

// 没有网络连接

break;

case ReachableViaWWAN:

// 使用3G网络

break;

case ReachableViaWiFi:

// 使用WiFi网络

break;

}

检查当前网络环境

程序启动时，如果想检测可用的网络环境，可以像这样

// 是否wifi

+ (BOOL) IsEnableWIFI {

return ([[Reachability reachabilityForLocalWiFi] currentReachabilityStatus] != NotReachable);

}

// 是否3G

+ (BOOL) IsEnable3G {

return ([[Reachability reachabilityForInternetConnection] currentReachabilityStatus] != NotReachable);

}

例子：

- (void)viewWillAppear:(BOOL)animated {

if (([Reachability reachabilityForInternetConnection].currentReachabilityStatus == NotReachable) &&

([Reachability reachabilityForLocalWiFi].currentReachabilityStatus == NotReachable)) {

self.navigationItem.hidesBackButton = YES;

[self.navigationItem setLeftBarButtonItem:nil animated:NO];

}

}

//
MyAppDelegate.m

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

Reachability* curReach = [note object];

NSParameterAssert([curReach isKindOfClass: [Reachability class]]);

NetworkStatus status = [curReach currentReachabilityStatus];

if (status == NotReachable) {

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"AppName""

message:@"NotReachable"

delegate:nil

cancelButtonTitle:@"YES" otherButtonTitles:nil];

[alert show];

[alert release];

}

}

- (void)applicationDidFinishLaunching:(UIApplication *)application {

// ...

// 监测网络情况

[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(reachabilityChanged:)

name: kReachabilityChangedNotification

object: nil];

hostReach = [[Reachability reachabilityWithHostName:@"www.google.com"] retain];

hostReach startNotifer];

// ...

}