[iOS]UIView添加阴影

• (void)viewDidLoad {
  [super viewDidLoad];
  [self addShadowToView:_floatView withColor:[UIColor blackColor]];
  }
  /// 添加四边阴影效果
• (void)addShadowToView:(UIView *)theView withColor:(UIColor *)theColor {
  // 阴影颜色
  theView.layer.shadowColor = theColor.CGColor;
  // 阴影偏移，默认(0, -3)
  theView.layer.shadowOffset = CGSizeMake(0,0);
  // 阴影透明度，默认0
  theView.layer.shadowOpacity = 0.5;
  // 阴影半径，默认3
  theView.layer.shadowRadius = 5;
  }

/// 添加单边阴影效果

• (void)addShadowToView:(UIView *)theView withColor:(UIColor *)theColor {
  theView.layer.shadowColor = theColor.CGColor;
  theView.layer.shadowOffset = CGSizeMake(0,0);
  theView.layer.shadowOpacity = 0.5;
  theView.layer.shadowRadius = 5;
  // 单边阴影 顶边
  float shadowPathWidth = theView.layer.shadowRadius;
  CGRect shadowRect = CGRectMake(0, 0-shadowPathWidth/2.0, theView.bounds.size.width, shadowPathWidth);
  UIBezierPath *path = [UIBezierPath bezierPathWithRect:shadowRect];
  theView.layer.shadowPath = path.CGPath;
  }

来自：https://blog.csdn.net/wsyx768/article/details/80859990