• iPhone网络编程之监视网络连接


    转载自http://hi.baidu.com/popln/blog/item/e6ed14884b2fa4a60f2444d1.html

      在当前的run循环中通过异步查询UIDevice当前的标志和网络状态,对网络连接状态进行监视。当连接状态变化时,观察者(observer)会以回调函数的形式接收到通知,从而做出相应的处理。

    #import <SystemConfiguration/SystemConfiguration.h>
    #include <netdb.h>
    #import <dlfcn.h>
    #import "UIDevice-Reachability.h"
    
    @implementation UIDevice (Reachability)
    SCNetworkConnectionFlags connectionFlags;
    SCNetworkReachabilityRef reachability;
    
    #pragma mark Checking Connections
    + (void) pingReachabilityInternal
    {
        if (!reachability)
        {
            BOOL ignoresAdHocWiFi = NO;
            struct sockaddr_in ipAddress;
            bzero(&ipAddress, sizeof(ipAddress));
            ipAddress.sin_len = sizeof(ipAddress);
            ipAddress.sin_family = AF_INET;
            ipAddress.sin_addr.s_addr = htonl(ignoresAdHocWiFi ? INADDR_ANY : IN_LINKLOCALNETNUM);
            
            reachability = SCNetworkReachabilityCreateWithAddress(kCFAllocatorDefault, (struct sockaddr *)&ipAddress);
            CFRetain(reachability);
        }
        
        // Recover reachability flags
        BOOL didRetrieveFlags = SCNetworkReachabilityGetFlags(reachability, &connectionFlags);
        if (!didRetrieveFlags) 
        printf("Error. Could not recover network reachability flags\n"); } #pragma mark Monitoring reachability static void ReachabilityCallback(SCNetworkReachabilityRef target, SCNetworkConnectionFlags flags, void* info) { NSAutoreleasePool *pool = [NSAutoreleasePool new]; [(id)info performSelector:@selector(reachabilityChanged)]; [pool release]; }
    // 开启网络连接监视
    + (BOOL) scheduleReachabilityWatcher: (id) watcher { if (![watcher conformsToProtocol:@protocol(ReachabilityWatcher)]) { NSLog(@"Watcher must conform to ReachabilityWatcher protocol. Cannot continue."); return NO; } [self pingReachabilityInternal]; SCNetworkReachabilityContext context = {0, watcher, NULL, NULL, NULL}; if(SCNetworkReachabilitySetCallback(reachability, ReachabilityCallback, &context)) { if(!SCNetworkReachabilityScheduleWithRunLoop(reachability, CFRunLoopGetCurrent(), kCFRunLoopCommonModes)) { NSLog(@"Error: Could not schedule reachability"); SCNetworkReachabilitySetCallback(reachability, NULL, NULL); return NO; } } else { NSLog(@"Error: Could not set reachability callback"); return NO; } return YES; } + (void) unscheduleReachabilityWatcher { SCNetworkReachabilitySetCallback(reachability, NULL, NULL); if (SCNetworkReachabilityUnscheduleFromRunLoop(reachability, CFRunLoopGetCurrent(), kCFRunLoopCommonModes)) NSLog(@"Unscheduled reachability"); else NSLog(@"Error: Could not unschedule reachability"); CFRelease(reachability); reachability = nil; } @end
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  • 原文地址:https://www.cnblogs.com/pure/p/2469522.html
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