飞屏，用手机播放电脑端视频的功能，一般常见于主打VR资源的影音类App。

大体思路：基于UDP协议的广播机制

电脑端不断发送udp广播，广播内容可精简为：端口号；
App用udpSocket扫描，得到对应端口号信息，解析出IP地址，拼接数据，请求数据。

移动端的实现：

1.导入第三方库：CocoaAsyncSocket，引用文件

#import <GCDAsyncUdpSocket.h>

2.遵守协议：

<GCDAsyncUdpSocketDelegate>```

######3.初始化对象，启动监听：

_clientSocket = [[GCDAsyncUdpSocket alloc] initWithDelegate:self delegateQueue:dispatch_get_main_queue()];   
NSError * error = nil;
[_clientSocket setIPv6Enabled:NO]; //�每次扫描，你会收到两条信息，IPv4和IPv6的，根据需求做取舍。
[_clientSocket bindToPort:8080error:&error];// 8080,与电脑端统一的端口号
 if (error) {
    PVRLog(@"clientSocket_error:%@",error);
 } else {
    [_clientSocket beginReceiving:&error];
    PVRLog(@"监听成功开始接收信息");
 }

#####4.代理回调

pragma mark - GCDAsyncUdpSocket delegate

• (void)udpSocket:(GCDAsyncUdpSocket *)sock didReceiveData:(NSData *)data fromAddress:(NSData *)address withFilterContext:(id)filterContext {

  NSString *sendMessage = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
  NSString *ip = [GCDAsyncUdpSocket hostFromAddress:address];
  uint16_t port = [GCDAsyncUdpSocket portFromAddress:address];
  PVRLog(@"接收到%@的消息,\n解析到的数据[%@:%d]",sendMessage,ip,port);

}

• (void)udpSocketDidClose:(GCDAsyncUdpSocket *)sock withError:(NSError *)error {
  PVRLog(@"udpSocket关闭withError = %@", error);
  }

####关于如何使用封装好的工具类，请参考代码
#####GitHub:https://github.com/YZQ-Nine/FlyScreenDemo