cocoa - WiFi网络更改是否有NSNotificationCenter通知？

Question

我想在我的 Cocoa 应用程序中订阅 WiFi 网络更改，但我找不到合适的事件来订阅。

WiFi网络更改是否有NSNotificationCenter通知？

Answer 1

据我所知不是。我会使用CoreWLAN获取系统上所有 WiFi 接口的列表，然后使用SystemConfiguration框架监控它们的状态。

这是一个命令行示例（省略了错误检查细节，需要 ARC）：

#import <Foundation/Foundation.h>
#import <CoreWLAN/CoreWLAN.h>
#import <SystemConfiguration/SystemConfiguration.h>

void wifi_network_changed(SCDynamicStoreRef store, CFArrayRef changedKeys, void *ctx)
{
  [(__bridge NSArray *)changedKeys enumerateObjectsUsingBlock:^(NSString *key, NSUInteger idx, BOOL *stop)
  {
    /* Extract the interface name from the changed key */
    NSString *ifName = [key componentsSeparatedByString:@"/"][3];
    CWInterface *iface = [CWInterface interfaceWithName:ifName];

    NSLog(@"%@ status changed: current ssid is %@, security is %ld",
          ifName, iface.ssid, iface.security);
  }];
}

int main(int argc, char *argv[])
{
  /* Get a list of all wifi interfaces, and build an array of SCDynamicStore keys to monitor */
  NSSet *wifiInterfaces = [CWInterface interfaceNames];
  NSMutableArray *scKeys = [[NSMutableArray alloc] init];
  [wifiInterfaces enumerateObjectsUsingBlock:^(NSString *ifName, BOOL *stop)
  {
    [scKeys addObject:
      [NSString stringWithFormat:@"State:/Network/Interface/%@/AirPort", ifName]];
  }];

  /* Connect to the dynamic store */
  SCDynamicStoreContext ctx = { 0, NULL, NULL, NULL, NULL };
  SCDynamicStoreRef store = SCDynamicStoreCreate(kCFAllocatorDefault,
                                                 CFSTR("myapp"),
                                                 wifi_network_changed,
                                                 &ctx);

  /* Start monitoring */
  SCDynamicStoreSetNotificationKeys(store,
                                    (__bridge CFArrayRef)scKeys,
                                    NULL);

  CFRunLoopSourceRef src = SCDynamicStoreCreateRunLoopSource(kCFAllocatorDefault, store, 0);
  CFRunLoopAddSource([[NSRunLoop currentRunLoop] getCFRunLoop],
                     src,
                     kCFRunLoopCommonModes);
  [[NSRunLoop currentRunLoop] run];
}

Answer 2

只要您保持打开 CWInterface，您就可以使用 CWLinkDidChangeNotification 等通知。在下面的代码中，i_interfaces 是一个 ivar，它存储了一个 CWInterface 数组，monitorWifi 应该在开始时调用，listInterfaces 列出接口值，handleInterfaceNotification 会在任何更改时调用。

请注意，当接口未连接时， iface.ssid / iface.bssid 将为 nil。

另请注意，由于各种通知，每次连接/断开连接都会多次调用handleInterfaceNotification。

此代码主要来自NSNotification 问题

-(void) listInterfaces;
{
    NSLog(@"listInterfaces");
    [i_interfaces enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop)
     {
         CWInterface *iface = obj;
         NSLog( @"iface %@, SSID %@, BSSID %@", iface, iface.ssid, iface.bssid );
     }];
}


-(void) handleInterfaceNotification:(NSNotification*) notification;
{
    NSLog(@"Notification Received");
    [self listInterfaces];
}

- (void) monitorWifi;
{
    NSLog(@"monitorWifi");

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleInterfaceNotification:) name:CWModeDidChangeNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleInterfaceNotification:) name:CWSSIDDidChangeNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleInterfaceNotification:) name:CWBSSIDDidChangeNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleInterfaceNotification:) name:CWCountryCodeDidChangeNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleInterfaceNotification:) name:CWLinkDidChangeNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleInterfaceNotification:) name:CWPowerDidChangeNotification object:nil];

    NSMutableArray* ifaces = [NSMutableArray new];
    NSSet *wifiInterfaces = [CWInterface interfaceNames];
    [wifiInterfaces enumerateObjectsUsingBlock:^(NSString *ifName, BOOL *stop)
     {
         CWInterface *iface = [CWInterface interfaceWithName:ifName];
         if ( iface ) {
             [ifaces addObject:iface];
         }
     }];
    i_interfaces = ifaces;

    [self listInterfaces];
}

Answer 3

高度赞赏。我需要从 Swift 中执行此操作，所以这里有一些 Swift 代码可以帮助您入门：

func callback(store: SCDynamicStore, changedKeys: CFArray, 
              context: UnsafeMutableRawPointer?) -> Void {
    // Do the magic
}

// Connect to the store
guard let store = SCDynamicStoreCreate(nil, "myapp" as CFString, callback, nil) else {
    print("Could not connect to store")
    abort()
}

// Setup the notification mechanism for any IPv4 event
var keys = [CFString]()
keys.append("State:/Network/Global/IPv4" as CFString)
SCDynamicStoreSetNotificationKeys(store, keys as CFArray, nil)

// Go into the loop
let runloop = SCDynamicStoreCreateRunLoopSource(nil, store, 0)
let currentLoop = RunLoop.current.getCFRunLoop()
let modes = CFRunLoopMode.commonModes
CFRunLoopAddSource(currentLoop, runloop, modes)
RunLoop.current.run()