//在向服务端发送请求状态栏显示网络活动标志：

[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];

//请求结束状态栏隐藏网络活动标志：

dispatch_async(dispatch_get_main_queue(), ^{

//状态栏隐藏活动

[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];

});