我想检查一下我是否可以在iOS上使用Cocoa Touch库或在macOS上使用Cocoa库连接互联网。
我想出了一个方法来做这个使用NSURL。我的方法似乎有点不可靠(因为即使谷歌也可能有一天宕机，依赖第三方似乎很糟糕)，虽然如果谷歌没有响应，我可以检查其他一些网站的响应，但这似乎是浪费和不必要的应用程序开销。
- (BOOL)connectedToInternet {
NSString *URLString = [NSString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.google.com"]];
return ( URLString != NULL ) ? YES : NO;
}
是我做得不好，(更不用说stringWithContentsOfURL已弃用在iOS 3.0和macOS 10.4)，如果是这样，有什么更好的方法来实现这一点?
当前回答
苹果提供了一个示例应用程序，它正是这样做的:
可达性
其他回答
这里有一个漂亮的，使用ARC和gcd的现代化可达性:
可达性
苹果提供了一个示例应用程序，它正是这样做的:
可达性
试试这个:
- (void) connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
if ([self.delegate respondsToSelector:@selector(getErrorResponse:)]) {
[self.delegate performSelector:@selector(getErrorResponse:) withObject:@"No Network Connection"];
}
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"BMC" message:@"No Network Connection" delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK",nil];
[alertView show];
}
首先:在framework中添加CFNetwork.framework
代码:ViewController.m
#import "Reachability.h"
- (void)viewWillAppear:(BOOL)animated
{
Reachability *r = [Reachability reachabilityWithHostName:@"www.google.com"];
NetworkStatus internetStatus = [r currentReachabilityStatus];
if ((internetStatus != ReachableViaWiFi) && (internetStatus != ReachableViaWWAN))
{
/// Create an alert if connection doesn't work
UIAlertView *myAlert = [[UIAlertView alloc]initWithTitle:@"No Internet Connection" message:NSLocalizedString(@"InternetMessage", nil)delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
[myAlert show];
[myAlert release];
}
else
{
NSLog(@"INTERNET IS CONNECT");
}
}
首先下载reachability类并放入reachability.h和reachability.h。m文件在你的Xcode。
最好的方法是创建一个通用的Functions类(NSObject)，这样你就可以在任何类中使用它。这是检查网络连接可达性的两种方法:
+(BOOL) reachabiltyCheck
{
NSLog(@"reachabiltyCheck");
BOOL status =YES;
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(reachabilityChanged:)
name:kReachabilityChangedNotification
object:nil];
Reachability * reach = [Reachability reachabilityForInternetConnection];
NSLog(@"status : %d",[reach currentReachabilityStatus]);
if([reach currentReachabilityStatus]==0)
{
status = NO;
NSLog(@"network not connected");
}
reach.reachableBlock = ^(Reachability * reachability)
{
dispatch_async(dispatch_get_main_queue(), ^{
});
};
reach.unreachableBlock = ^(Reachability * reachability)
{
dispatch_async(dispatch_get_main_queue(), ^{
});
};
[reach startNotifier];
return status;
}
+(BOOL)reachabilityChanged:(NSNotification*)note
{
BOOL status =YES;
NSLog(@"reachabilityChanged");
Reachability * reach = [note object];
NetworkStatus netStatus = [reach currentReachabilityStatus];
switch (netStatus)
{
case NotReachable:
{
status = NO;
NSLog(@"Not Reachable");
}
break;
default:
{
if (!isSyncingReportPulseFlag)
{
status = YES;
isSyncingReportPulseFlag = TRUE;
[DatabaseHandler checkForFailedReportStatusAndReSync];
}
}
break;
}
return status;
}
+ (BOOL) connectedToNetwork
{
// Create zero addy
struct sockaddr_in zeroAddress;
bzero(&zeroAddress, sizeof(zeroAddress));
zeroAddress.sin_len = sizeof(zeroAddress);
zeroAddress.sin_family = AF_INET;
// Recover reachability flags
SCNetworkReachabilityRef defaultRouteReachability = SCNetworkReachabilityCreateWithAddress(NULL, (struct sockaddr *)&zeroAddress);
SCNetworkReachabilityFlags flags;
BOOL didRetrieveFlags = SCNetworkReachabilityGetFlags(defaultRouteReachability, &flags);
CFRelease(defaultRouteReachability);
if (!didRetrieveFlags)
{
NSLog(@"Error. Could not recover network reachability flags");
return NO;
}
BOOL isReachable = flags & kSCNetworkFlagsReachable;
BOOL needsConnection = flags & kSCNetworkFlagsConnectionRequired;
BOOL nonWiFi = flags & kSCNetworkReachabilityFlagsTransientConnection;
NSURL *testURL = [NSURL URLWithString:@"http://www.apple.com/"];
NSURLRequest *testRequest = [NSURLRequest requestWithURL:testURL cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:20.0];
NSURLConnection *testConnection = [[NSURLConnection alloc] initWithRequest:testRequest delegate:self];
return ((isReachable && !needsConnection) || nonWiFi) ? (testConnection ? YES : NO) : NO;
}
现在您可以通过调用这个类方法来检查任何类中的网络连接。
