IPhone network programming first-time chat program instance Development

IPhone Network ProgrammingInitial ExperienceChat programThis document describes how to implement instance development.Chat programFor more information, see the content first. First, use Xcode to name a common View-based application project named Network.

Use network communication flow

The simplest way to use sockets to communicate over the network is to use the NSStream class, which is an abstract class that represents a stream. You can use it to read and write data, it can be used in memory, files, or networks. With the NSStream class, you can write data to the server or read data from the server.

On Mac OS X, you can use the NSHost and NSStream objects to establish a connection to the server, for example:

 
 

  
  
NSInputStream *iStream;  
  
  
            NSOutputStream *oStream;  
  
  
            uint portNo = 500;  
  
  
            NSURL *website = [NSURL URLWithString:urlStr];  
  
  
            NSHost *host = [NSHost hostWithName:[website host]];  
  
  
            [NSStream getStreamsToHost:host  
  
  
                                  port:portNo  
  
  
                           inputStream:&iStream  
  
  
                          outputStream:&oStream]; 
 
 

The NSStream class has a method getStreamsToHost: port: inputStream: outputStream:, which creates an input and output stream to the server, but the problem is that iPhone OS does not support getStreamsToHost: port: inputStream: outputStream: therefore, the above Code cannot run in the iPhone application.

To solve this problem, you can add a category to the existing NSStream class and replace the functions provided by the getStreamsToHost: port: inputStream: outputStream: method. Right-click the Classes in Xcode and add the NSStreamAdditions. m file. In the NSStreamAdditions. h file, add the following code:

 
 

  
  
#import  
  
  
@interface NSStream (MyAdditions)  
  
  
+ (void)getStreamsToHostNamed:(NSString *)hostName  
  
  
                         port:(NSInteger)port  
  
  
                  inputStream:(NSInputStream **)inputStreamPtr  
  
  
                 outputStream:(NSOutputStream **)outputStreamPtr;  
  
  
@end 
 
 

Add the following code to the NSStreamAdditions file:

 
 

  
  
#import "NSStreamAdditions.h"  
  
  
@implementation NSStream (MyAdditions)  
  
  
+ (void)getStreamsToHostNamed:(NSString *)hostName  
  
  
                          port:(NSInteger)port  
  
  
                   inputStream:(NSInputStream **)inputStreamPtr  
  
  
                  outputStream:(NSOutputStream **)outputStreamPtr  
  
  
 {  
  
  
     CFReadStreamRef     readStream;  
  
  
     CFWriteStreamRef    writeStream;  
  
  
     assert(hostName != nil);  
  
  
     assert( (port > 0) && (port < 65536) );  
  
  
     assert( (inputStreamPtr != NULL) || (outputStreamPtr != NULL) );  
  
  
     readStream = NULL;  
  
  
     writeStream = NULL;  
  
  
     CFStreamCreatePairWithSocketToHost(  
  
  
                                        NULL,  
  
  
                                        (CFStringRef) hostName,  
  
  
                                        port,  
  
  
                                        ((inputStreamPtr  != nil) ? &readStream : NULL),  
  
  
                                        ((outputStreamPtr != nil) ? &writeStream : NULL)  
  
  
                                        );  
  
  
         if (inputStreamPtr != NULL) {  
  
  
        *inputStreamPtr  = [NSMakeCollectable(readStream) autorelease];  
  
  
     }  
  
  
     if (outputStreamPtr != NULL) {  
  
  
         *outputStreamPtr = [NSMakeCollectable(writeStream) autorelease];  
  
  
     }  
  
  
 }  
  
  
 @end 
 
 

The above Code adds a getStreamsToHostNamed: port: inputStream: outputStream: method to the NSStream class. Now you can use this method in your iPhone application to connect to the server using the TCP protocol.

In the NetworkViewController. m file, insert the following code:

 
 

  
  
#import "NetworkViewController.h"  
  
  
#import "NSStreamAdditions.h"  
  
  
@implementation NetworkViewController  
  
  
NSMutableData *data;  
  
  
NSInputStream *iStream;  
  
  
NSOutputStream *oStream; 
 
 

Define connectToServerUsingStream: portNo: Method to connect to the server, and then create input and output stream objects:

 
 

  
  
-(void) connectToServerUsingStream:(NSString *)urlStr  
  
  
                            portNo: (uint) portNo {  
  
  
    if (![urlStr isEqualToString:@""]) {  
  
  
        NSURL *website = [NSURL URLWithString:urlStr];  
  
  
        if (!website) {  
  
  
            NSLog(@"%@ is not a valid URL");  
  
  
            return;  
  
  
        } else {  
  
  
            [NSStream getStreamsToHostNamed:urlStr  
  
  
                                       port:portNo  
  
  
                                inputStream:&iStream  
  
  
                               outputStream:&oStream];              
  
  
            [iStream retain];  
  
  
            [oStream retain];  
  
  
            [iStream setDelegate:self];  
  
  
            [oStream setDelegate:self];  
  
  
              
  
  
            [iStream scheduleInRunLoop:[NSRunLoop currentRunLoop]   forMode:NSDefaultRunLoopMode];  
  
  
            [oStream scheduleInRunLoop:[NSRunLoop currentRunLoop]   forMode:NSDefaultRunLoopMode];  
  
  
            [oStream open];  
  
  
            [iStream open];              
  
  
        }  
  
  
}      
  
  
} 
 
 

In a running loop, you can schedule input and output streams to receive events to avoid blocking.

Summary:IPhone Network ProgrammingInitial ExperienceChat programI hope this article will help you with the introduction of instance development!