- (id)readViewControllerFromStoryBoardWithIdentifier:(NSString *)identifier
{
return [[UIStoryboard storyboardWithName:@"ELVStoryBoard" bundle:nil] instantiateViewControllerWithIdentifier:identifier];
}
[backBtn setImageEdgeInsets:UIEdgeInsetsMake(0, 0, 0, 44)];
根据identifier从StoryBoard中获取对象，UIButton的图片文件位置
原文：http://www.cnblogs.com/hanjian/p/4506501.html