1. initWithFrame: - It is recommended that you implement this method. You can also implement custom initialization methods in addition to, or instead of, this method.

  2. initWithCoder: - Implement this method if you load your view from an Interface Builder nib file and your view requires custom initialization.

UIView和XIB

  1. 首先自定义下UIView
  2. 再创建一个Xib文件
  3. Xib中随便拖拽几个UIView
  4. 设置File owner为自定义UIView
  5. 连接一个View到自定义UIView
  6. 添加到ViewController中测试

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如果在finishInit 中不执行 
Bundle.main.loadNibNamed("CustomView", owner: self, options: nil)
将报错。因为我们已经将一个UIView 和 自定义View连线，执行load以后默认就会初始化View

屏幕快照 2017-02-14 11.34.38

```利用@IBDesignable 在Storeboard中直接显示自定义View

1. 在自定义View Class 添加 @IBDesignable
2. 在storyboard ->ViewController 拖拽一个UIView ， class 改成我们自定义View

可惜storyboard 报错了，IB Designables: Failed to update auto layout status: The agent raised a “NSInternalInconsistencyException” exception: Could not load NIB in bundle: ‘NSBundle </Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/Xcode/Overlays> (loaded)’ with name ‘CustomView’


```查看错误信息应该表示Bundle 无法加载NIB
通过在网上查找资料，问题其实是这样的。

When loading the nib, we're relying on the fact that passing bundle: nil defaults to your app's mainBundle at run time.
我们修改代码，将Bundle.main.loadNibNamed("CustomView", owner: self, options: nil) 改为
Bundle(for: CustomView.self).loadNibNamed("CustomView", owner: self, options: nil)
再查看下，结果显示正确

屏幕快照 2017-02-14 11.57.24