我知道有 another similar question ,但它适用于旧版本的 AFNetworking,并且无论如何都没有真正回答它。
我有以下代码:
AFHTTPRequestOperationManager* manager = [AFHTTPRequestOperationManager manager];
manager.securityPolicy.allowInvalidCertificates = YES;
manager.requestSerializer = [AFJSONRequestSerializer serializer];
[manager.requestSerializer setAuthorizationHeaderFieldWithUsername: currentUser() password: currentPassword()];
__block NSDictionary* response = nil;
AFHTTPRequestOperation* operation = [manager
GET: @"https://10.20.30.40:8765/foobar"
parameters: [NSDictionary dictionary]
success:^(AFHTTPRequestOperation* operation, id responseObject){
response = responseObject;
NSLog(@"response (block): %@", response);
}
failure:^(AFHTTPRequestOperation* operation, NSError* error){
NSLog(@"Error: %@", error);}
];
[operation waitUntilFinished];
NSLog(@"response: %@", response);
...
如果我运行它,我将在我的日志中看到的是:
2013-12-09 09:26:20.105 myValve[409:60b] response: (null)
2013-12-09 09:26:20.202 myValve[409:60b] response (block): {
F00005 = "";
F00008 = "";
F00013 = "";
}
在waitUntilFinished
之后 的NSLog
首先触发。我预计它会第二次开火。我错过了什么?
最佳答案
几个想法:
问题是
waitUntilFinished
将等待核心网络操作完成,但不会等待成功
或失败
完成 block 。如果你想等待完成 block ,你可以使用信号量:__block NSDictionary* response = nil; dispatch_semaphore_t semaphore = dispatch_semaphore_create(0); manager.completionQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0); AFHTTPRequestOperation* operation = [manager GET: @"https://10.20.30.40:8765/foobar" parameters: [NSDictionary dictionary] success:^(AFHTTPRequestOperation* operation, id responseObject){ response = responseObject; NSLog(@"response (block): %@", response); dispatch_semaphore_signal(semaphore); } failure:^(AFHTTPRequestOperation* operation, NSError* error){ NSLog(@"Error: %@", error); dispatch_semaphore_signal(semaphore); }]; NSLog(@"waiting"); dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER); // [operation waitUntilFinished]; NSLog(@"response: %@", response);
或者,您可以将其包装在您自己的并发
NSOperation
子类中,在AFHTTPRequestOperation
完成 block 中发布isFinished
,消除进程中的信号量
。注意,如果在主队列上执行信号量,请确保指定
completionQueue
因为,在没有它的情况下,AFNetworking 默认将完成处理程序分派(dispatch)到主队列,您可能会死锁。顺便说一句,你永远不应该阻塞主队列(糟糕的用户体验,你的应用程序可能会被看门狗进程杀死,等等),所以如果你从主队列这样做,我会劝阻
waitUntilFinished
或信号量的使用。最好从完成 block 中启动任何你需要的东西,让主队列在这个异步网络操作正在进行时继续执行,例如:[activityIndicatorView startAnimating]; AFHTTPRequestOperation* operation = [manager GET: @"https://10.20.30.40:8765/foobar" parameters: [NSDictionary dictionary] success:^(AFHTTPRequestOperation* operation, id responseObject){ // do whatever you want with `responseObject` here // now update the UI, e.g.: [activityIndicatorView stopAnimating]; [self.tableView reloadData]; } failure:^(AFHTTPRequestOperation* operation, NSError* error){ // put your error handling here // now update the UI, e.g.: [activityIndicatorView stopAnimating]; }]; // NSLog(@"waiting"); // dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER); // // [operation waitUntilFinished]; // NSLog(@"response: %@", response);
听起来您想让您的模型让 UI 在模型对象完成更新后进行任何必要的更新。因此,您可以使用自己的 block 参数,以便 View Controller 可以告诉模型对象在完成时做什么(而不是使用 waitUntilFinished
或信号量来使网络操作阻塞主队列)。例如,假设您的模型有这样的方法:
- (void)updateModelWithSuccess:(void (^)(void))success failure:(void (^)(NSError *error))failure
{
AFHTTPRequestOperationManager* manager = [AFHTTPRequestOperationManager manager];
manager.securityPolicy.allowInvalidCertificates = YES;
manager.requestSerializer = [AFJSONRequestSerializer serializer];
[manager.requestSerializer setAuthorizationHeaderFieldWithUsername: currentUser() password: currentPassword()];
AFHTTPRequestOperation* operation = [manager GET: @"https://10.20.30.40:8765/foobar"
parameters: [NSDictionary dictionary]
success:^(AFHTTPRequestOperation* operation, id responseObject){
// do your model update here
// then call the success block passed to this method (if any),
// for example to update the UI
if (success)
success();
}
failure:^(AFHTTPRequestOperation* operation, NSError* error){
NSLog(@"Error: %@", error);
// if caller provided a failure block, call that
if (failure)
failure(error);
}];
}
然后你的 View Controller 可以做类似的事情:
[modelObject updateModelWithSuccess:^{
// specify UI updates to perform upon success, e.g.
// stop activity indicator view, reload table, etc.
} failure:^(NSError *error){
// specify any UI updates to perform upon failure
}]
最重要的是,您的代码可以使用 AFNetworking 使用的相同样式的完成 block 。如果您希望模型将信息传回,您可以向完成 block 本身添加额外的参数,但我认为以上说明了基本思想。
关于ios - AFNetworking-2 waitUntilFinished 不工作,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/20476957/