ios - AFNetworking 成功/失败 block 是否在主线程上调用？

Question

AFNetworking 是否在主线程上调用完成 block ？还是在后台调用，需要我手动将 UI 更新分派(dispatch)到主线程？

使用代码而不是文字，这是来自 AFNetworking documentation 的示例代码调用 NSLog 替换为 UI 更新:

AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
    self.label.text = JSON[@"text"];
} failure:nil];

应该这样写吗？

AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
    dispatch_async(dispatch_get_main_queue(), ^{
        self.label.text = JSON[@"text"];
    });
} failure:nil];

Answer 1

它们在主队列上调用，除非您在 AFHTTPRequestOperation 上显式设置队列，如 AFHTTPRequestOperation.m 中的 setCompletionBlockWithSuccess:failure 所示>

self.completionBlock = ^{
    if (self.error) {
        if (failure) {
            dispatch_async(self.failureCallbackQueue ?: dispatch_get_main_queue(), ^{
                failure(self, self.error);
            });
        }
    } else {
        if (success) {
            dispatch_async(self.successCallbackQueue ?: dispatch_get_main_queue(), ^{
                success(self, self.responseData);
            });
        }
    }
};