iphone - NSStreams 崩溃程序!

Question

全部，

我已经通过注释、断点等方式将它运行到这一点。程序在标记的代码处崩溃。

-(void) initNetworkCommunication
{
    CFReadStreamRef readStream;
    CFWriteStreamRef writeStream;
    CFStreamCreatePairWithSocketToHost(NULL, (CFStringRef)@"192.168.17.1", 2004, &readStream, &writeStream);

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

    [inputStream open];//WHY MUST YOU CRASH HERE
    [outputStream open];//WHY MUST YOU CRASH HERE ALSO!!?!?

    NSLog(@"She be opened, sir!");
}

如果我注释掉这两个，它不会崩溃，但如果我注释掉其中一个，它就会崩溃(也就是说，它们都会导致程序崩溃)。调试器中也没有发布任何信息。它所做的就是将我发送到 main.m 并显示给我

“线程 1:程序收到信号:“EXC_BAD_ACCESS”。

提前感谢您的帮助!

编辑:这是我的委托(delegate)方法，但它甚至没有在日志中显示第二个事件行。

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

    NSLog(@"stream event %i", streamEvent); //this doesn't post in the log when stream opened...

    switch (streamEvent) {

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

            if (theStream == 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);
                            //[self messageReceived:output];

                        }
                    }
                }
            }
            break;


        case NSStreamEventErrorOccurred:

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

        case NSStreamEventEndEncountered:

            [theStream close];
            [theStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
            //[theStream release];
            theStream = nil;

            break;
        default:
            NSLog(@"Unknown event");
    }

} 

Answer 1

正在发生的事情是委托(delegate)类的实例正在被释放(在运行循环中导致 EXC_BAD_ACCESS)，要么是因为您没有保留它，要么是因为您正在使用 ARC(很可能)并且您没有引用给它。

解决方案是在委托(delegate)类上调用 retain，大致如下:

SomeStreamDelegate *theDelegate = [[SomeStreamDelegate alloc] init];
[theDelegate retain];

或者，如果您确实启用了 ARC，请在您分配委托(delegate)的类中创建一个实例变量，并将您的连接实例存储在那里。这样 ARC 就不会释放它，因为实例 var 算作一个引用。