问题
BACKGROUND: I made an IPhone socket application based on UDP. It works as a client and server while it communicates with a Linux [Ubuntu] server. I’m using a GCDAsyncUdpSocket to send and receive data. I also have a back-up server/client application on my Macbook to test/verify the socket communication application. It simply acts like the Linux [Ubuntu] server. It works perfect.
PROBLEM: I can’t receive any data from the Linux [Ubuntu] server.
DETAILS: I can successfully send data to the Linux server and it reacts/processes upon that data. But when the server sends replies or echoes, my iPhone app can't see/read it. A similar application I developed with a colleague for Android does read/see data from the server. Please see the code below. Cheers!
This is the code for it: .m file:
-(void)viewDidLoad
{
[super viewDidLoad];
backGround.userInteractionEnabled=YES;
udpSocket = [[GCDAsyncUdpSocket alloc] initWithDelegate:self delegateQueue:dispatch_get_main_queue()];
NSError *error = nil;
if (![udpSocket bindToPort:0 error:&error]) //check ff of dit werkt!
{
return;
}
if (![udpSocket beginReceiving:&error])
{
return;
}
}
- (IBAction)sendData:(id)sender
{
NSString *msg = messageField.text;
NSData *data = [msg dataUsingEncoding:NSUTF8StringEncoding];
[self sendingRealData:data];
}
-(void)sendingRealData:(NSData *) Content
{
NSString *msg = [[NSString alloc] initWithData:Content encoding:NSUTF8StringEncoding];
NSLog(@"msg is: %@", msg);
NSString *host = [self getHost];
int port = [self getPort];
if ((port == 65536) && (host == @"-1"))
{
NSLog(@"Port and IP are not filled in!");
[self errorManag:2];
}
else if ((port == 65536) && (host != @"-1"))
{
NSLog(@"return was -2");
[self errorManag:1];
}
else if (host == @"-1")
{
NSLog(@"return was -1");
[self errorManag:0];
}
else
{
[udpSocket sendData:Content toHost:host port:port withTimeout:1 tag:tag];
NSLog(@"Gestuurd");
}
}
- (void)udpSocket:(GCDAsyncUdpSocket *)sock didReceiveData:(NSData *)data
fromAddress:(NSData *)address
withFilterContext:(id)filterContext
{
NSLog(@"niets.");
NSString *msg = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
if (msg)
{
NSLog(@"iets gekregen");
}
else
{
NSLog(@"Error convertion");
//[self logError:@"Error converting received data into UTF-8 String"];
}
//NSString *test = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
//NSLog(@"%@",test);
//[udpSocket sendData:data toAddress:address withTimeout:-1 tag:0];
NSLog(@"HMMMM");
messageField.text = [[NSString alloc] initWithFormat:@"RE: %@", msg];
}
回答1:
I found out that I had written in the ViewDidLoad to bind to port: 0, because this advice was given to me before.
This caused the mobile to listen to a random port instead of port 12345. Changing the binding to port 12345 and works!
来源：https://stackoverflow.com/questions/10313278/receiving-data-from-udp-server-on-ios-app-is-not-working-from-linux-server-but