UIButtonに枠線をつける
xxx.h
@property (strong, nonatomic) IBOutlet UIButton *btn;
xxx.m
#import <QuartzCore/QuartzCore.h>
- (void)initView {
[[self.btn layer] setBorderColor:[[UIColor blackColor] CGColor]];
[[self.btn layer] setBorderWidth:2.0];
[[self.btn layer] setCornerRadius:10.0];
[self.btn setClipsToBounds:YES];
}