iOS：outputStream不會保持打開

Question

好吧，我正在實現NSOutput和Input Streams。當它們被初始化時，流打開並連接到我的PC上運行的TCPServer，但在初始化函數之外似乎關閉一次，或者流可能沒有正確存儲。我不太清楚，所以任何幫助是極大的讚賞

在我的.h文件：

@interface AVCamViewController : UIViewController <UIImagePickerControllerDelegate,UINavigationControllerDelegate, NSStreamDelegate> { 
    NSOutputStream *outputStream; 
    NSInputStream *inputStream; 
} 

@property (retain) NSInputStream *inputStream; 
@property (retain) NSOutputStream *outputStream; 

在我的.m文件：

@synthesize inputStream, outputStream; 

    -(void)sendaResponse 
    { 
     NSString *response = [NSString stringWithFormat:@"Hello from Ipad Simulator"]; 
     NSData *data = [[NSData alloc] initWithData:[response dataUsingEncoding:NSASCIIStringEncoding]]; 
     [outputStream write:[data bytes] maxLength:[data length]]; 
     NSLog(@"%u", outputStream.streamStatus); 
    } 

    -(void)initNetworkCommunication 
    { 
     CFReadStreamRef readStream; 
     CFWriteStreamRef writeStream; 
     CFStreamCreatePairWithSocketToHost(NULL, (CFStringRef)@"10.9.100.122", 80, &readStream, &writeStream); 

     NSInputStream *inputStream = (NSInputStream *) readStream; 
     NSOutputStream *outputStream = (NSOutputStream *) writeStream; 

     [inputStream setDelegate:self]; 
     [outputStream setDelegate:self]; 
     [inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; 
     [outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; 
     [inputStream open]; 
     [outputStream open]; 


     NSLog(@"%u and %u", inputStream.streamStatus, outputStream.streamStatus); 
     NSString *response = [NSString stringWithFormat:@"Hello from Mikes Ipad Simulator"]; 
     NSData *data = [[NSData alloc] initWithData:[response dataUsingEncoding:NSASCIIStringEncoding]]; 
     [outputStream write:[data bytes] maxLength:[data length]]; 
     NSLog(@"%u", outputStream.streamStatus); 
    } 

    -(void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode 
    { 
     switch (eventCode) { 
      case NSStreamEventOpenCompleted: 
       NSLog(@"Stream Opened %u", outputStream.streamStatus); 
       break; 

      case NSStreamEventHasBytesAvailable: 
       if(aStream == inputStream) 
       { 
        uint8_t buffer [1024]; 
        int len; 

        while ([inputStream hasBytesAvailable]) 
        { 
         len = [inputStream read:buffer maxLength:sizeof(buffer)]; 
         if(len>0) 
         { 
          NSString *output = [[NSString alloc] initWithBytes:buffer length:len encoding:NSASCIIStringEncoding]; 

          if(nil != output) 
          { 
           NSLog(@"Server said: %@", output); 
          } 
         } 
        } 
       } 
       break; 

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

      case NSStreamEventEndEncountered: 
       if(aStream == inputStream) 
        NSLog(@"Ending input stream"); 
       if(aStream == outputStream) 
        NSLog(@"Ending output stream"); 

       [aStream close]; 
       [aStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; 
       [aStream release]; 
       aStream = nil; 
       break; 

      default: 
       break; 
     } 
    } 

在initNetworkConnection模擬器連接到我TCPServer並打開一個連接（streamstatus = 2）。接收到消息「Ipad Simulator Hello」。 但是，然後我有一個按鈕點擊調用「sendaResponse」方法，然後streamstatus = 0和「outputstream」似乎沒有被初始化。我只是沒有正確保留變量？

Answer 1

我假設你正在使用ARC。 中刪除此代碼：

{ 
NSOutputStream *outputStream; 
NSInputStream *inputStream; 
} 

@synthesize inputStream, outputStream; 

這只是迷惑你的屬性和實例變量之間。並且它的結果是你直接設置實例變量，並且你的流實例被ARC解除分配。

取而代之，一旦您刪除了上面的代碼，請使用self.inputStream和self.outputStream訪問流。這將允許屬性正常工作，並確保您配置的「保留」規範得到遵守。

您的原始代碼也可能只是沒有嘗試設置屬性... 你的配置應該是：

NSInputStream *inputStream = (NSInputStream *) readStream; 
    NSOutputStream *outputStream = (NSOutputStream *) writeStream; 

    [inputStream setDelegate:self]; 
    [outputStream setDelegate:self]; 
    [inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; 
    [outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode]; 
    [inputStream open]; 
    [outputStream open]; 

self.inputStream = inputStream; 
self.outputStream = outputStream; 

然後，更改屬性：

@property (strong) NSInputStream *inputStream; 
@property (strong) NSOutputStream *outputStream;