实例如下：
// 获取网络环境的方法
+ (NSString *)networktype{
NSArray *subviews = [[[[UIApplication sharedApplication] valueForKey:@statusBar] valueForKey:@foregroundView]subviews];
NSNumber *dataNetworkItemView = nil;
for (id subview in subviews) {
if([subview isKindOfClass:[NSClassFromString(@UISt
