UIImage* itemImage= [UIImage imageNamed:@"notification-app-icon"];
itemImage = [itemImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
UIBarButtonItem * itemLocation =[[UIBarButtonItem alloc]initWithImage:itemImage style:UIBarButtonItemStylePlain target:self action:nil];
主要就是要设置图片的UIImageRenderingModeAlwaysOriginal
