向我的UIView添加投影的最佳方法是什么

6 回答

• 62

  试试这个：

  UIBezierPath *shadowPath = [UIBezierPath bezierPathWithRect:view.bounds];
  view.layer.masksToBounds = NO;
  view.layer.shadowColor = [UIColor blackColor].CGColor;
  view.layer.shadowOffset = CGSizeMake(0.0f, 5.0f);
  view.layer.shadowOpacity = 0.5f;
  view.layer.shadowPath = shadowPath.CGPath;
  

  First of all ：用作 shadowPath 的 UIBezierPath 至关重要 . 如果你没有't use it, you might not notice a difference at first, but the keen eye will observe a certain lag occurring during events like rotating the device and/or similar. It'进行重要的性能调整 .

  Regarding your issue specifically ：重要的一行是 view.layer.masksToBounds = NO . 它禁用视图's layer's子图层的剪切，这些子图层比视图的边界延伸得更远 .

  对于那些想知道 masksToBounds （在图层上）和视图自己的 clipToBounds 属性之间的区别是：实际上并没有 . 切换一个会影响另一个 . 只是一个不同的抽象层次 .

  ---

  Swift 2.2：

  override func layoutSubviews()
  {
      super.layoutSubviews()
  
      let shadowPath = UIBezierPath(rect: bounds)
      layer.masksToBounds = false
      layer.shadowColor = UIColor.blackColor().CGColor
      layer.shadowOffset = CGSizeMake(0.0, 5.0)
      layer.shadowOpacity = 0.5
      layer.shadowPath = shadowPath.CGPath
  }
  

  ---

  斯威夫特3：

  override func layoutSubviews()
  {
      super.layoutSubviews()
  
      let shadowPath = UIBezierPath(rect: bounds)
      layer.masksToBounds = false
      layer.shadowColor = UIColor.black.cgColor
      layer.shadowOffset = CGSize(width: 0.0, height: 5.0)
      layer.shadowOpacity = 0.5
      layer.shadowPath = shadowPath.cgPath
  }
  

  回复于 2024-05-02T07:42:35+08:00
• 13

  Wasabii在Swift 2.3中的回答：

  let shadowPath = UIBezierPath(rect: view.bounds)
      view.layer.masksToBounds = false
      view.layer.shadowColor = UIColor.blackColor().CGColor
      view.layer.shadowOffset = CGSize(width: 0, height: 0.5)
      view.layer.shadowOpacity = 0.2
      view.layer.shadowPath = shadowPath.CGPath
  

  在Swift 3/4中：

  let shadowPath = UIBezierPath(rect: view.bounds)
      view.layer.masksToBounds = false
      view.layer.shadowColor = UIColor.black.cgColor
      view.layer.shadowOffset = CGSize(width: 0, height: 0.5)
      view.layer.shadowOpacity = 0.2
      view.layer.shadowPath = shadowPath.cgPath
  

  如果您正在使用AutoLayout，请将此代码放在layoutSubviews（）中 .

  回复于 2024-05-02T07:42:35+08:00
• 265

  诀窍是正确定义视图层的 masksToBounds 属性：

  view.layer.masksToBounds = NO;
  

  它应该工作 .

  （Source）

  回复于 2024-05-02T07:42:35+08:00
• 13

  您可以为UIView创建扩展，以在设计编辑器中访问这些值

  

  extension UIView{
  
      @IBInspectable var shadowOffset: CGSize{
          get{
              return self.layer.shadowOffset
          }
          set{
              self.layer.shadowOffset = newValue
          }
      }
  
      @IBInspectable var shadowColor: UIColor{
          get{
              return UIColor(cgColor: self.layer.shadowColor!)
          }
          set{
              self.layer.shadowColor = newValue.cgColor
          }
      }
  
      @IBInspectable var shadowRadius: CGFloat{
          get{
              return self.layer.shadowRadius
          }
          set{
              self.layer.shadowRadius = newValue
          }
      }
  
      @IBInspectable var shadowOpacity: Float{
          get{
              return self.layer.shadowOpacity
          }
          set{
              self.layer.shadowOpacity = newValue
          }
      }
  }
  

  回复于 2024-05-02T07:42:35+08:00
• 1

  您也可以从故事板为视图设置阴影

  

  回复于 2024-05-02T07:42:35+08:00
• 6

  在viewWillLayoutSubviews上：

  override func viewWillLayoutSubviews() {
      sampleView.layer.masksToBounds =  false
      sampleView.layer.shadowColor = UIColor.darkGrayColor().CGColor;
      sampleView.layer.shadowOffset = CGSizeMake(2.0, 2.0)
      sampleView.layer.shadowOpacity = 1.0
  }
  

  使用UIView的扩展：

  extension UIView {
  
      func addDropShadowToView(targetView:UIView? ){
          targetView!.layer.masksToBounds =  false
          targetView!.layer.shadowColor = UIColor.darkGrayColor().CGColor;
          targetView!.layer.shadowOffset = CGSizeMake(2.0, 2.0)
          targetView!.layer.shadowOpacity = 1.0
      }
  }
  

  用法：

  sampleView.addDropShadowToView(sampleView)
  

  回复于 2024-05-02T07:42:35+08:00