iPhone开发技巧之网络篇（4）--- 确认网络环境 3G/WIFI

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// the network state of the device for Reachability 1.5.
typedef enum {
NotReachable = 0,
ReachableViaCarrierDataNetwork,
ReachableViaWiFiNetwork
} NetworkStatus;

// the network state of the device for Reachability 2.0.
typedef enum {
NotReachable = 0,
ReachableViaWiFi,
ReachableViaWWAN
} NetworkStatus;

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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;
}

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// 是否wifi
+ (BOOL) IsEnableWIFI {
return ([[Reachability reachabilityForLocalWiFi] currentReachabilityStatus] != NotReachable);
}

// 是否3G
+ (BOOL) IsEnable3G {
return ([[Reachability reachabilityForInternetConnection] currentReachabilityStatus] != NotReachable);
}

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// My.AppDelegate.h

#import "Reachability.h"

@interface MyAppDelegate : NSObject <UIApplicationDelegate> {
NetworkStatus remoteHostStatus;
}

@property NetworkStatus remoteHostStatus;

@end

// My.AppDelegate.m

#import "MyAppDelegate.h"

@implementation MyAppDelegate

@synthesize remoteHostStatus;

// 更新网络状态
- (void)updateStatus {
self.remoteHostStatus = [[Reachability sharedReachability] remoteHostStatus];
}

// 通知网络状态
- (void)reachabilityChanged:(NSNotification *)note {
[self updateStatus];
if (self.remoteHostStatus == NotReachable) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"AppName", nil) message:NSLocalizedString(@"NotReachable", nil)
delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil];
[alert show];
[alert release];
}
}

// 程序启动器，启动网络监视
- (void)applicationDidFinishLaunching:(UIApplication *)application {

// 设置网络检测的站点
[[Reachability sharedReachability] setHostName:@"www.apple.com"];
[[Reachability sharedReachability] setNetworkStatusNotificationsEnabled:YES];
// 设置网络状态变化时的通知函数
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(reachabilityChanged:)
name:@"kNetworkReachabilityChangedNotification" object:nil];
[self updateStatus];
}

- (void)dealloc {
// 删除通知对象
[[NSNotificationCenter defaultCenter] removeObserver:self];
[window release];
[super dealloc];
}

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// MyAppDelegate.h

@class Reachability;

@interface MyAppDelegate : NSObject <UIApplicationDelegate> {
Reachability  *hostReach;
}

@end

// 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];
// ...
}