信号量先执行block再return

dispatch_semaphore_t signal = dispatch_semaphore_create(0);

dask = [NetWorkManager PostWithUrl:KAPI_RCIM_ConversationRelation Params:@{@"token":[UserManager share].userModel.token, @"to_user_id": modelIDString} successHander:^(id reponse) {
        if ([reponse[@"code"] integerValue] == 0) {
            dispatch_semaphore_signal(signal);
        }else {
            dispatch_semaphore_signal(signal);
        }
} returnFailHander:^(id returnFail) {
        dispatch_semaphore_signal(signal);
} failHander:^(NSError *error) {
        dispatch_semaphore_signal(signal);
}];
    
dispatch_semaphore_wait(signal, DISPATCH_TIME_FOREVER);
return someThing;

最近发现不好使了，因为AFN把回调放在主线程了

image.png

需要设置一下manager的线程：

manager.completionQueue = dispatch_get_global_queue(0, 0);

dispatch_semaphore_t signal = dispatch_semaphore_create(0);
AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
manager.responseSerializer.acceptableContentTypes = [NSSet setWithObjects: @"application/json", @"text/html", @"text/json", nil];
manager.requestSerializer.timeoutInterval = 30;
manager.completionQueue = dispatch_get_global_queue(0, 0);
[manager POST:@"http://www.test.com/" parameters:nil progress:nil success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
    dispatch_semaphore_signal(signal);
        
} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
    dispatch_semaphore_signal(signal);
}];
    
dispatch_semaphore_wait(signal, DISPATCH_TIME_FOREVER);

而且不要在afn回调的block里进行UI修改，会报这个错：
Main Thread Checker: UI API called on a background thread
把更新UI操作放到dispatch_semaphore_wait(signal, DISPATCH_TIME_FOREVER);后面就可以了