UIButton

按鈕型別

按鈕的型別定義其基本外觀和行為。建立按鈕後，你無法更改其型別。最常用的按鈕型別是自定義和系統型別，但在適當時使用其他型別

• UIButtonTypeCustom

  No button style.
  

• UIButtonTypeSystem

  A system style button, such as those shown in navigation bars and toolbars.
  

• UIButtonTypeDetailDisclosure

  A detail disclosure button.
  

• UIButtonTypeInfoLight

  An information button that has a light background.
  

• UIButtonTypeInfoDark

  An information button that has a dark background.
  

• UIButtonTypeContactAdd

  A contact add button.
  

建立自定義按鈕（即自定義型別的按鈕）時，按鈕的框架最初設定為（0,0,0,0）。在將按鈕新增到介面之前，應將幀更新為更合適的值。