iphone - 单例实现从服务器读/写

Question

我正在尝试实现一个单例来从简单的聊天服务器读取/写入。我使用单例模型，以便我可以访问数据并从所有 View Controller 写入。

我的单例代码:

#import "ChatDataController.h"

@implementation ChatDataController
{
    ChatDataController * anotherSingles;
}

@synthesize enString;
@synthesize enInt;


+(ChatDataController *) singlOjb {

    static ChatDataController * single=nil;

    @synchronized(self)
    {
        if(!single)
        {
            single = [[ChatDataController alloc] init];
        }
    }

    return single;
}


// We can still have a regular init method, that will get called the first time the Singleton is used.
- (id)init
{
    self = [super init];

    if (self) {
        // Work your initialising magic here as you normally would

        [self initNetworkCommunication];
    }

    return self;
}

// Open connection to server
- (void)initNetworkCommunication {
    CFReadStreamRef readStream;
    CFWriteStreamRef writeStream;
    CFStreamCreatePairWithSocketToHost(NULL, (CFStringRef)@"localhost", 8080, &readStream, &writeStream);
    inputStream = (__bridge NSInputStream *)readStream;
    outputStream = (__bridge NSOutputStream *)writeStream;

    [inputStream setDelegate:self];
    [outputStream setDelegate:self];

    [inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    [outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];

    [inputStream open];
    [outputStream open];
}

- (void) sendMsg {
    NSString *response  = [NSString stringWithFormat:@"iam:TestString"];
    NSData *data = [[NSData alloc] initWithData:[response dataUsingEncoding:NSASCIIStringEncoding]];
    [outputStream write:[data bytes] maxLength:[data length]];
}

@end

问题是，当我从 init 方法运行 [self initNetworkCommunication]; 时，我的应用程序崩溃并出现错误:(lldb)

检测到线路中断:inputStream = (__bridge NSInputStream *)readStream;

知道我做错了什么吗？

编辑:这是我应该这样做的方式吗？

Answer 1

首先，你的单例代码应该是这样的......

+ (ChatDataController *)sharedInstance
{
    static dispatch_once_t once;
    static ChatDataController *chatDataController;
    dispatch_once(&once, ^ { chatDataController = [[ChatDataController alloc] init];});
    return chatDataController;
}

接下来，我不确定这是否会解决，因为我不确定确切的问题，但我会这样做......

在您的 AppDelegate(或任何您需要启动流的地方)执行此操作...

[[ChatDataController sharedInstance] initNetworkCommunication];

这确保单例对象在调用其实例方法之前已完全实例化。