http://www.cnblogs.com/hanjun/archive/2012/12/01/2797622.html

網絡連接中用到的類：

一.Reachability?

? ? 1.添加?Reachability 的.h和.m文件，再添加SystemConfiguration.framework。

? ? 2.Reachability中定義了三種網絡狀態：

? typedef Num{

NotReachable = 0, ?//無連接

ReachableViaWiFi, ?//使用3G/GPRS網絡

ReachableViaWWAN? ?//使用WiFi網絡

? ? ? ?}NetworkStatus;

? ? ?3.示例：

??Reachability *reachability = [Reachablity ?reachabilityWithHostName:@"www.baidu.com"];

? switch([reachabilityStatus]){

case??NotReachable:

//TODO?

break;?

case ?ReachableViaWiFi:

//TODO ?

break;?

case ?ReachableViaWWAN:

//TODO ?

break;??

?}?

? ? ? 4.檢查當前網絡環境

程序啟動時，如果想檢測可用的網絡環境，可以像這樣來使用

? //是否wifi

+ (BOOL)isEnableWIFI?

{

return ([[Reachability reachabiliyForLocalWIFI] currentReachabilityStatus] != NotReachable);?

? ?}

?

?? //是否3G

+ (BOOL)isEnable3G

{

return ([[Reachability reachabiliyForInternetConnetion] currentReachabilityStatus] != NotReachable);?

? ?}

?

?? 示例：

- (void)viewWillAppear:(BOOL)animated

{?

? if (([Reachability reachabiliyForInternetConnetion].currentReachabilityStatus ==?NotReachable) &&?[Reachability ? ? ? ? ? ? ? ? ? ? ? ? reachabiliyForLocalWIFI].currentReachabilityStatus == NotReachable))

{

self.navigationItem.hidesBackButton = YES;

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

}?

?

?}?

?

? ? ? ?5.鏈接狀態的實時通知

實時檢查，持續狀態發生變化時，需要及時地通知用戶：

?

Reachability?1.5版本
//MyAppDelegate.h

#import?"Reachability"

@interface?MyAppDelegate:NSObject<UIApplicationDelegate>
{
????
}

@property?NetworkStatus?remoteHostStatus;

@end?

?

?//MyAppDelegate.m

#import?"MyAppDelegate.h"

@implementation?MyAppDelegate
@synthesize?remoteHostStatus;

//更新網絡狀態
-?(void)updateStatus
{
????self.remoteHostStatus?=?[[Reachability?sharedReachability]?remoteHostStatus];
}

//通知網絡狀態
-?(void)reachabilityChanged:(NSNotification?*)note
{
????[self?updateStatus];
????if?(self.remoteHostStatus?==?NotReachable)
???{
???????UIAlert?*alert?=?[[UIAlertView?alloc]?initWithTitle:NSLocalizedString(@"AppName",nil)
??message:?NSLocalizedString?(@"NotReachable",nil);
??delegate:nil?cancelButtonTitle:@"OK"?
??otherButtonTitles:nil];

???[alert?show];
???[alert?release];
????}
}


//程序啟動器，啟動網絡監視
-?(void)applicationDidFinishLaunching:(UIApplication?*)application
{
???//設置網絡監測的站點
???[[Reachability?sharedReachability]?setHostName:@"www.baidu.com"];
???[[Reachability?sharedReachability]?setNetworkStatusNotificationsEnabled:YES];

???//設置網絡狀態變化時的通知函數
???[[NSNotificationCenter?defaultCenter]?addObserver:self?selector:@selector(reachabilityChanged:)?
name:@"kNetworkReachabilityChangedNotification"?object:nil];
???[self?updateStatus];


}

-?(void)dealloc
{
????//刪除通知對象
????[[NSNotificationCenter?defaultCenter]?removeObserver:self];
????[window?release];
????[super?dealloc];
}

?

?

Reachability?2.0版本
//MyAppDelegate.h

#import?"Reachability"
@class?Reachability;
@interface?MyAppDelegate:NSObject<UIApplicationDelegate>
{
?????Reachability?*hostReach;
}


@end?
?
?//MyAppDelegate.m

#import?"MyAppDelegate.h"

@implementation?MyAppDelegate

//通知網絡狀態
-?(void)reachabilityChanged:(NSNotification?*)note
{
????Reachability?*currentReach?=?[note?object];
????NSParameterAssert([currentReach?isKindOfClass:[Reachability?class]]);
????NetworkStatus?status?=?[currentReach?currentReachabilityStatus];?

????if?(status?==?NotReachable)
???{
???????UIAlert?*alert?=?[[UIAlertView?alloc]?initWithTitle:NSLocalizedString(@"AppName",nil)
??message:?NSLocalizedString?(@"NotReachable",nil);
??delegate:nil?cancelButtonTitle:@"YES"?
??otherButtonTitles:nil];

???[alert?show];
???[alert?release];
????}
}


//程序啟動器，啟動網絡監視
-?(void)applicationDidFinishLaunching:(UIApplication?*)application
{
???//....

???//監測網絡情況
???[[NSNotificationCenter?defaultCenter]?addObserver:self?selector:@selector(reachabilityChanged:)?
name:@"kNetworkReachabilityChangedNotification"?object:nil];
??hostReach?=?[[Reachability?reachabilityWithHostName:@"www.baidu.com"]?retain];
?//?hostReach?startNotifer];?
???//...


}

?

?

二、其他常用的類。

?1.NSURL

?2.NSURLRequest

?3.NSMutableURLRequest 是NSURLRequest的子類，可以設置一些請求參數

?4.NSURLResponse?

?5.NSError?

轉載于:https://www.cnblogs.com/xuejinhui/p/4469624.html

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