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我正在使用一个名为 WiFly 的设备，其 IP 地址为：169.254.1.1 和端口 2000。我正在尝试通过 iOS 应用程序连接到该设备。我使用以下代码进行连接：

CFReadStreamRef readStream;
CFWriteStreamRef writeStream;

UInt32 port = 2000;
CFStringRef host = CFSTR("169.254.1.1");

CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault, host, port, &readStream, &writeStream);

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

// set the delegates to this view controller
[inputStream setDelegate:self];
[outputStream setDelegate:self];

// Set run loops to continuous receive information
[inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];

// Finally, open the connection
[inputStream open];
[outputStream open];

然后我使用以下内容来处理流事件：

- (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent {
    NSLog(@"stream event %i", streamEvent);

    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't connect to server");
            break;

        case NSStreamEventEndEncountered:
            [theStream close];
            [theStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
            break;

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

因此，我可以看到前两个流已正确打开。然后紧随其后的是流事件 4，据我了解，这是可以预料的。但是，然后我尝试调用一个函数：

- (IBAction)moveForward
{
    NSLog(@"move forward called");
    NSString *response  = [NSString stringWithFormat:@"2"];
    NSData *data = [[NSData alloc] initWithData:[response dataUsingEncoding:NSASCIIStringEncoding]];
    [outputStream write:[data bytes] maxLength:[data length]];
}

哪个应该通过wifly从arduino uno返回“前进”。但是，当我单击时，由于某种原因，我得到了另一个 NSStreamEvent 4。我还通过终端远程登录到设备：

远程登录 169.254.1.1 2000

然后键入“2”...这立即返回了所需的“转发”。从 iPad 的角度来看，我做错了什么？

此外，这段代码在几周前就开始工作了。但是一旦我更新了模拟器，它就停止了工作......连接正常打开，但 arduino 设备似乎没有从 iOS 获得输出。

非常感谢您的帮助！

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2 回答 2

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NSStreamEvent 4 是 NSStreamEventHasSpaceAvailable。您必须等到输出流有可用空间后才能发送数据。

于 2014-04-20T19:55:40.897 回答
-1

尝试替换 NSString *response = [NSString stringWithFormat:@"2"]; 使用这个 NSString *response = [NSString stringWithFormat:@"%d",2]; 在 moveForward 方法中。

于 2013-07-23T12:55:40.083 回答