iOS网络编程实践–NSStream实现TCP Socket iPhone客户端


客户端我们使用iPhone应用程序,画面比较简单。点击发送按钮,给服务器发送一些字符串过去。点击接收按钮就会从服务器读取一些字符串,并且显示在画面上。

iOS网络编程实践--NSStream实现TCP Socket iPhone客户端

有关客户端应用的UI部分不再介绍了,我们直接看代码部分,Socket客户端可以采用CFStream或NSStream实现。为了给读者介绍更多的知识,本例我们采用NSStream实现。NSStream实现采用Objective-C语言,一些面向对象的类。

下面我们看看客户端视图控制器ViewController.h

#import <CoreFoundation/CoreFoundation.h>  #include <sys/socket.h>  #include <netinet/in.h>     #define PORT 9000     @interface ViewController : UIViewController<NSStreamDelegate>  {  int flag ; //操作标志 0为发送 1为接收  }     @property (nonatomic, retain) NSInputStream *inputStream;  @property (nonatomic, retain) NSOutputStream *outputStream;     @property (weak, nonatomic) IBOutlet UILabel *message;     - (IBAction)sendData:(id)sender;  - (IBAction)receiveData:(id)sender;     @end

定义属性inputStream和outputStream,它们输入流NSInputStream和输出流NSOutputStream类。它们与服务器CFStream实现中的输入流CFReadStreamRef和输出流CFWriteStreamRef对应的。

视图控制器ViewController.m的初始化网络方法initNetworkCommunication代码:

- (void)initNetworkCommunication  {  CFReadStreamRef readStream;  CFWriteStreamRef writeStream;  CFStreamCreatePairWithSocketToHost(NULL,  (CFStringRef)@”192.168.1.103″, PORT, &readStream, &writeStream);   ①  _inputStream = (__bridge_transfer NSInputStream *)readStream; ②  _outputStream = (__bridge_transfer NSOutputStream*)writeStream;  ③  [_inputStream setDelegate:self];  ④  [_outputStream setDelegate:self];  ⑤  [_inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop]  forMode:NSDefaultRunLoopMode]; ⑥  [_outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop]  forMode:NSDefaultRunLoopMode];  ⑦  [_inputStream open];  ⑧  [_outputStream open];  ⑨  }  点击发送和接收按钮触发的方法如下:  /* 点击发送按钮  */  - (IBAction)sendData:(id)sender {  flag = 0;  [self initNetworkCommunication];  }  /* 点击接收按钮  */  - (IBAction)receiveData:(id)sender {  flag = 1;  [self initNetworkCommunication];  }

它们都调用initNetworkCommunication方法,并设置操作标识flag,如果flag0发送数据,flag1接收数据。

流的状态的变化触发很多事件,并回调NSStreamDelegate协议中定义的方法stream:handleEvent:,其代码如下:

-(void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent {  NSString *event;  switch (streamEvent) {  case NSStreamEventNone:  event = @”NSStreamEventNone”;  break;  case NSStreamEventOpenCompleted:  event = @”NSStreamEventOpenCompleted”;  break;  case NSStreamEventHasBytesAvailable:  event = @”NSStreamEventHasBytesAvailable”;  if (flag ==1 && theStream == _inputStream) {  NSMutableData *input = [[NSMutableData alloc] init];  uint8_t buffer[1024];  ①  int len;  while([_inputStream hasBytesAvailable]) ②  {  len = [_inputStream read:buffer maxLength:sizeof(buffer)];  ③  if (len > 0)  {  [input appendBytes:buffer length:len];  }  }  NSString *resultstring = [[NSString alloc]  initWithData:input encoding:NSUTF8StringEncoding];  NSLog(@”接收:%@”,resultstring);  _message.text = resultstring;  }  break;  case NSStreamEventHasSpaceAvailable:  event = @”NSStreamEventHasSpaceAvailable”;  if (flag ==0 && theStream == _outputStream) {  //输出  UInt8 buff[] = ”Hello Server!”; ④  [_outputStream write:buff maxLength: strlen((const char*)buff)+1]; ⑤  //关闭输出流  [_outputStream close];  }  break;  case NSStreamEventErrorOccurred:  event = @”NSStreamEventErrorOccurred”;  [self close]; ⑥  break;  case NSStreamEventEndEncountered:  event = @”NSStreamEventEndEncountered”;  NSLog(@”Error:%d:%@”,[[theStream streamError] code],  [[theStream streamError] localizedDescription]);  break;  default:  [self close];  ⑦  event = @”Unknown”;  break;  }  NSLog(@”event——%@”,event);  }

在读取数据分支(NSStreamEventHasBytesAvailable)中,代码第①行为读取数据准备缓冲区,本例中设置的是1024个字节,这个大小会对流的读取有很多的影响。第②行代码使用hasBytesAvailable方法判断是否流有数据可以读,如果有可读数据就进行循环读取。第③行代码使用流的read:maxLength:方法读取数据到缓冲区,第1个参数是缓冲区对象buffer,第2个参数是读取的缓冲区的字节长度。

在写入数据分支(NSStreamEventHasSpaceAvailable)中,代码第④行是要写入的数据,第⑤行代码[_outputStream write:buff maxLength: strlen((const char*)buff)+1]是写如数据方法。

第⑥和第⑦行代码[self close]调用close方法关闭,close方法代码如下:

-(void)close  {  [_outputStream close];  [_outputStream removeFromRunLoop:[NSRunLoop currentRunLoop]  forMode:NSDefaultRunLoopMode];  [_outputStream setDelegate:nil];  [_inputStream close];  [_inputStream removeFromRunLoop:[NSRunLoop currentRunLoop]  forMode:NSDefaultRunLoopMode];  [_inputStream setDelegate:nil];  }

12 responses on “iOS网络编程实践–NSStream实现TCP Socket iPhone客户端

发表评论

电子邮件地址不会被公开。 必填项已用*标注

您可以使用这些HTML标签和属性: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>