UIViewAutoresizingNone = 0, UIViewAutoresizingFlexibleLeftMargin = 1 << 0, UIViewAutoresizingFlexibleWidth = 1 << 1, UIViewAutoresizingFlexibleRightMa
UIViewAutoresizingNone = 0, UIViewAutoresizingFlexibleLeftMargin = 1 << 0, UIViewAutoresizingFlexibleWidth = 1 << 1, UIViewAutoresizingFlexibleRightMargin = 1 << 2, UIViewAutoresizingFlexibleTopMargin = 1 << 3, UIViewAutoresizingFlexibleHeight = 1 << 4, UIViewAutoresizingFlexibleBottomMargin = 1 << 5
控制視圖與superview的位置,大小變化
UIViewAutoresizingNone:superview變換時,不作變換。
UIViewAutoresizingFlexibleHeight:上邊距不變,superview在高度上增加減少多少高度 ,view也同等的增減,做相應的變化。
UIViewAutoresizingFlexibleTopMargin:高度不變。上邊距彈性可變,下邊距保持不變。
UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleHeight: 下邊距不變,高度和上邊距可變且變化的比例為:(superView的原高度 - 下邊距)/(superview變化後的高度 - 下邊距 )。
UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleBottomMargin : 上邊距,高,下邊距都和superview同比變換
autoresizesSubviews預設為YES。