The default implementation of this method does nothing on iOS 5.1 and earlier. Otherwise, the default implementation uses any constraints you have set to determine the size and position of any subviews.
iOS - layoutSubviews總結(jié)(作用及調(diào)用機制)iOS layout機制相關(guān)方法 layoutSubviews在以下情況下會被調(diào)用: 1、init初始化不會觸發(fā)layoutSubviews但是是用initWithFrame...