UIView的圆角矩形效果 关键是修改layer

//导入QuartzCore库
#import "QuartzCore/CALayer.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
[super viewDidLoad];
UIView * view = [[UIView alloc] initWithFrame:CGRectMake(50, 50, 60, 60)];
view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"2"]];
view.layer.cornerRadius = 6;
view.layer.masksToBounds = YES;
[self.view addSubview:view];
[view release];
}