如果maskToBounds为YES,则圆角显示,否则为阴影显示.这是实现,但它只显示没有阴影的圆角：

[self.view setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:@"blue_gradient.jpeg"]]];


    self.view.layer.masksToBounds = YES; 
    self.view.layer.opaque = NO; 
    self.view.layer.cornerRadius = 15.0f; 


    self.view.layer.shadowColor = [UIColor blackColor].CGColor;
    self.view.layer.shadowRadius = 5.0; 
    self.view.layer.shadowOffset = CGSizeMake(3.0,3.0);
    self.view.layer.shadowOpacity = 0.9f;

想法！

注意：我已经阅读并实现了以下线程中的代码,但它不起作用：
UIView with rounded corners and drop shadow?

更新1：

我试图创建两个单独的视图.一个将代表半径,一个将代表阴影.问题是在半径视图的顶部创建阴影,如下面的屏幕截图所示：

H

ere is the code: 

 self.view.layer.masksToBounds = YES; 
    self.view.layer.opaque = NO; 
    self.view.layer.cornerRadius = 15.0f; 
   // self.view.backgroundColor = [UIColor clearColor];
    self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"blue_gradient.jpeg"]];
//
    UIView *shadowView = [[UIView alloc] initWithFrame:CGRectMake(0,100,100)];
    shadowView.layer.shadowColor = [UIColor blackColor].CGColor;
    shadowView.layer.shadowRadius = 2.0; 
    shadowView.backgroundColor = [UIColor clearColor];
    shadowView.layer.shadowOffset = CGSizeMake(3.0,3.0);
    shadowView.layer.shadowOpacity = 0.9f;
    shadowView.layer.shadowPath = [UIBezierPath 
                                                                   bezierPathWithRect:CGRectMake(0,100)].CGPath;

    [self.view addSubview:shadowView];

更新2：

倒置仍然不行.没有创建圆角.

UIView *roundCornerView = [[UIView alloc] initWithFrame:CGRectMake(0,100)];
    roundCornerView.layer.masksToBounds = YES; 
    roundCornerView.layer.opaque = NO; 
    roundCornerView.layer.cornerRadius = 15.0f; 

    self.view.layer.shadowColor = [UIColor blackColor].CGColor;
    self.view.layer.shadowRadius = 2.0; 
    //self.view.backgroundColor = [UIColor clearColor];
    self.view.layer.shadowOffset = CGSizeMake(3.0,3.0);
    self.view.layer.shadowOpacity = 0.9f;
    self.view.layer.shadowPath = [UIBezierPath 
                                                                   bezierPathWithRect:CGRectMake(0,100)].CGPath;

    [self.view addSubview:roundCornerView];

解：

UIView *roundCornerView = [[UIView alloc] initWithFrame:CGRectMake(0,100)];
    roundCornerView.layer.masksToBounds = YES; 
    roundCornerView.layer.opaque = NO; 
    roundCornerView.layer.cornerRadius = 15.0f; 

    roundCornerView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"blue_gradient.jpeg"]];

    self.view.layer.shadowColor = [UIColor blackColor].CGColor;
    self.view.layer.shadowRadius = 2.0; 
    self.view.backgroundColor = [UIColor clearColor];
    self.view.layer.shadowOffset = CGSizeMake(3.0,3.0);
    self.view.layer.shadowOpacity = 0.9f;
    //self.view.layer.shadowPath = [UIBezierPath 
      //                                                             bezierPathWithRect:CGRectMake(0,100)].CGPath;

    [self.view addSubview:roundCornerView];