UISearchBar 的使用

1.UISearchBar 去掉背景、自定义边框（不喜欢自带的的边框阴影可以使用）

[[[searchBar subviews] objectAtIndex:0] setAlpha:0];    UITextField *field = (UITextField*)[[searchBar subviews] objectAtIndex:1];field.background = nil;field.backgroundColor = [UIColor clearColor];field.borderStyle = UITextBorderStyleNone;field.layer.borderWidth = 1.f;field.layer.borderColor = [UIColor colorWithRed:217/255.0 green:217/255.0 blue:217/255.0 alpha:1].CGColor;field.layer.cornerRadius = 14.0f;[field setReturnKeyType:UIReturnKeySearch];