旧线程仍然当前…

我编辑了Daniel Gindi的方法，使它可以用于按钮等。 如果有人需要圆角，或者想要将圆角和边框结合起来，它必须在视图层上设置，这个视图层被传递给这个方法。我还设置了栅格化来加快一点。

+ (UIView*)putView:(UIView*)view insideShadowWithColor:(CGColorRef)color 
                                 andRadius:(CGFloat)shadowRadius 
                                 andOffset:(CGSize)shadowOffset 
                                 andOpacity:(CGFloat)shadowOpacity
{
    // Must have same position like "view"
    UIView *shadow = [[UIView alloc] initWithFrame:view.frame]; 

    shadow.layer.contentsScale = [UIScreen mainScreen].scale;
    shadow.userInteractionEnabled = YES; // Modify this if needed
    shadow.layer.shadowColor = color;
    shadow.layer.shadowOffset = shadowOffset;
    shadow.layer.shadowRadius = shadowRadius;
    shadow.layer.masksToBounds = NO;
    shadow.clipsToBounds = NO;
    shadow.layer.shadowOpacity = shadowOpacity;
    shadow.layer.rasterizationScale = [UIScreen mainScreen].scale;
    shadow.layer.shouldRasterize = YES;

    [view.superview insertSubview:shadow belowSubview:view];
    [shadow addSubview:view];

    // Move view to the top left corner inside the shadowview 
    // ---> Buttons etc are working again :)
    view.frame = CGRectMake(0, 0, view.frame.size.width, view.frame.size.height);

    return shadow;
}

Evan Mulawski提供的答案将会非常有效。问题是你必须将视图的背景色设置为clearColor，并将masksToBounds属性设置为NO。

你可以为视图设置任何你想要的颜色

v.layer.backgroundColor = your color;

希望这能有所帮助。

如果你因为圆角、子视图和masksToBounds而挣扎，那么尝试使用我的函数:

- (UIView*)putView:(UIView*)view insideShadowWithColor:(UIColor*)color andRadius:(CGFloat)shadowRadius andOffset:(CGSize)shadowOffset andOpacity:(CGFloat)shadowOpacity
{
    CGRect shadowFrame; // Modify this if needed
    shadowFrame.size.width = 0.f;
    shadowFrame.size.height = 0.f;
    shadowFrame.origin.x = 0.f;
    shadowFrame.origin.y = 0.f;
    UIView * shadow = [[UIView alloc] initWithFrame:shadowFrame];
    shadow.userInteractionEnabled = NO; // Modify this if needed
    shadow.layer.shadowColor = color.CGColor;
    shadow.layer.shadowOffset = shadowOffset;
    shadow.layer.shadowRadius = shadowRadius;
    shadow.layer.masksToBounds = NO;
    shadow.clipsToBounds = NO;
    shadow.layer.shadowOpacity = shadowOpacity;
    [view.superview insertSubview:shadow belowSubview:view];
    [shadow addSubview:view];
    return shadow;
}

在你的视图中调用它。无论你的视图是否有圆角，无论它的大小，它的形状-一个漂亮的阴影将被绘制出来。

只要保留函数的返回值，这样当你想要删除表时就可以引用它(或者例如使用insertSubview:aboveView:)

如果你不想像David c建议的那样改变你的nibs和视图层次结构，这个方法可以帮你。为你的UIImageView添加圆角和阴影只需使用这个方法，例如:

[Utils roundCornersForImageView:myImageView withCornerRadius:6.0 
andShadowOffset:2.0];

(!)出于性能原因，我不认为在像UITableView这样的东西中使用这段代码是个好主意，因为这段代码改变了视图层次结构。所以我会建议改变你的nib，并添加一个容器视图的阴影效果和使用戴维C.代码。

+ (void)roundCornersForImageView:(UIImageView *)imageView 
withCornerRadius:(float)cornerRadius andShadowOffset:(float)shadowOffset
{
    const float CORNER_RADIUS = cornerRadius;
    const float BORDER_WIDTH = 1.0; 
    const float SHADOW_OFFSET = shadowOffset;
    const float SHADOW_OPACITY = 0.8;
    const float SHADOW_RADIUS = 3.0;

    //Our old image now is just background image view with shadow
    UIImageView *backgroundImageView = imageView;
    UIView *superView = backgroundImageView.superview;

    //Make wider actual visible rect taking into account shadow
    //offset
    CGRect oldBackgroundFrame = backgroundImageView.frame;
    CGRect newBackgroundFrame = CGRectMake(oldBackgroundFrame.origin.x, oldBackgroundFrame.origin.y, oldBackgroundFrame.size.width + SHADOW_OFFSET, oldBackgroundFrame.size.height + SHADOW_OFFSET);
    [backgroundImageView removeFromSuperview];
    backgroundImageView.frame = newBackgroundFrame;        

    //Make new UIImageView with rounded corners and put our old image
    CGRect frameForRoundedImageView = CGRectMake(0, 0, oldBackgroundFrame.size.width, oldBackgroundFrame.size.height);
    UIImageView *roundedImageView = [[UIImageView alloc]initWithFrame:frameForRoundedImageView];
    roundedImageView.image = imageView.image;
    [roundedImageView.layer setCornerRadius:CORNER_RADIUS];
    [roundedImageView.layer setBorderColor:[UIColor lightGrayColor].CGColor];        
    [roundedImageView.layer setBorderWidth:BORDER_WIDTH]; 
    [roundedImageView.layer setMasksToBounds:YES];

    //Set shadow preferences
    [backgroundImageView setImage:nil];
    [backgroundImageView.layer setShadowColor:[UIColor blackColor].CGColor];
    [backgroundImageView.layer setShadowOpacity:SHADOW_OPACITY];
    [backgroundImageView.layer setShadowRadius:SHADOW_RADIUS];
    [backgroundImageView.layer setShadowOffset:CGSizeMake(SHADOW_OFFSET, SHADOW_OFFSET)];   

    //Add out two image views back to the view hierarchy.
    [backgroundImageView addSubview:roundedImageView];
    [superView addSubview:backgroundImageView];   
}    

当为容器视图分配阴影路径时，我使用以下技巧解决了这个问题:

[UIBezierPath bezierPathWithRoundedRect:cell.bounds cornerRadius:12]

请注意，阴影的路径是一个圆角矩形，与单元格包含的背景具有相同的角半径:

//this is the border for the UIView that is added to a cell
cell.backgroundView.layer.cornerRadius = 12;
cell.backgroundView.layer.masksToBounds = YES;
cell.backgroundView.layer.borderColor = [UIColor darkGrayColor].CGColor;
cell.backgroundView.layer.borderWidth = 1;

//this is the shadow around the cell itself (cannot have round corners with borders and shadow, need to use two views
cell.layer.shadowRadius = 2;
cell.layer.cornerRadius = 12;
cell.layer.masksToBounds = NO;
[[cell layer] setShadowColor:[[UIColor darkGrayColor] CGColor]];

[[cell layer] setShadowOffset:CGSizeMake(0.0,0.0)];
[[cell layer] setShadowOpacity:1.0];

UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:cell.bounds cornerRadius:12];
[[cell layer] setShadowPath:[path CGPath]];

这里是masksToBounds冲突问题的解决方案，它适用于我。

在你设置corderRadius/borderColor/shadow等之后，将masksToBounds设置为NO:

v.layer.masksToBounds = NO;