NSStream处理事件给予状态4

Question

我正在尝试TCP连接应用程序,我在handleEvent上获得了一个NSStreamEvent"4".我究竟做错了什么？

我的代码就像,

-(void) initNetworkCommunication {

CFReadStreamRef readStream;
CFWriteStreamRef writeStream;
CFStreamCreatePairWithSocketToHost(NULL, (CFStringRef)@"localhost", 80, &readStream, &writeStream);

inputStream = (__bridge_transfer NSInputStream *)readStream;
outputStream = (__bridge_transfer NSOutputStream *)writeStream;
[inputStream setDelegate:self];
[outputStream setDelegate:self];
[inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[inputStream open];
[outputStream open];

}


- (IBAction)didTapButton:(id)sender {

NSString *response  = inputTextField.text;
NSLog(@"%@", response);
NSData *data = [[NSData alloc] initWithData:[response dataUsingEncoding:NSASCIIStringEncoding]];
[outputStream write:[data bytes] maxLength:[data length]];
}



 - (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent {

  switch (streamEvent) {

    case NSStreamEventOpenCompleted:
        NSLog(@"Stream opened");
        break;

    case NSStreamEventHasBytesAvailable:
        NSLog(@"Stream has bytes available");

        break;          

    case NSStreamEventErrorOccurred:
        NSLog(@"Can not connect to the host!");
        break;

    case NSStreamEventEndEncountered:
        NSLog(@"Stream closed");

        break;

    default:

        NSLog(@"Unknown event: %@ : %d", theStream, streamEvent);
    }

  }

控制台给出,

2012-05-29 13:37:07.132 GestureTrial[24289:f803] Stream opened
2012-05-29 13:37:07.133 GestureTrial[24289:f803] Stream opened
2012-05-29 13:37:07.133 GestureTrial[24289:f803] Unknown event: <__NSCFOutputStream: 0x6b85c70> : 4

当试图向服务器发送消息时.我尝试使用适用于Mac的tcp测试器应用程序,它工作正常,因此可能不是防火墙问题.设备和模拟器的输出相同.任何帮助将非常感激.

Answer 1

其实你没有做错任何事.

此事件(它NSStreamEventHasSpaceAvailable)通常在写入流之后出现,告诉您流已准备好再次写入并在打开可写流之后.请参考NSStream类参考,或者确切地说:流事件常量.

如果您不熟悉<<运算符,则意味着将位移位到左侧n个位置(每个位移等于乘以2).翻译将是:

typedef enum {
   NSStreamEventNone = 0,
   NSStreamEventOpenCompleted = 1,
   NSStreamEventHasBytesAvailable = 2,
   NSStreamEventHasSpaceAvailable = 4,
   NSStreamEventErrorOccurred = 8,
   NSStreamEventEndEncountered = 16
};

在许多应用程序中,您将简单地忽略(未处理)此事件,因为它通常在写入流后很快就会出现.如果出现问题你会得到NSStreamEventErrorOccurred或者NSStreamEventEndEncountered这些是你需要处理的.您可以使用NSStreamEventHasSpaceAvailable标志,可以发送更多数据.

您还应该知道两个流(inputStream和outputStream)都在调用相同的委托方法.这就是为什么你NSStreamEventOpenCompleted要开始两个事件.但在许多情况下,这不应该是一个问题.如果需要,您始终可以检查哪个流是事件的发起者.