enum UIViewAutoresizing {
UIViewAutoresizingNone = 0,
UIViewAutoresizingFlexibleLeftMargin = 1 << 0,
UIViewAutoresizingFlexibleWidth = 1 << 1,
UIViewAutoresizingFlexibleRightMargin = 1 << 2,
UIViewAutoresizingFlexibleTopMargin = 1 << 3,
UIViewAutoresizingFlexibleHeight = 1 << 4,
UIViewAutoresizingFlexibleBottomMargin = 1 << 5,
}”
這個<<是什么意思?
位操作法蚂踊，即往左移動N位仗谆，舉個例子，1的二進(jìn)制表示是1扒吁，往左移一位就是10火鼻。這種枚舉是一般叫做option室囊。舉個例子UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleWidth就是 01 | 10 即11
順便提一下動畫的枚舉
0A7BB0BB-621A-4548-807D-4475164E4EF5.png
typedef NS_OPTIONS(NSUInteger, UIViewAnimationOptions) {
UIViewAnimationOptionLayoutSubviews = 1 << 0, //提交動畫的時候布局子控件，表示子控件將和父控件一同動畫魁索。
UIViewAnimationOptionAllowUserInteraction = 1 << 1, //動畫時允許用戶交流融撞，比如觸摸
UIViewAnimationOptionBeginFromCurrentState = 1 << 2, //從當(dāng)前狀態(tài)開始動畫
UIViewAnimationOptionRepeat = 1 << 3, //動畫無限重復(fù)
UIViewAnimationOptionAutoreverse = 1 << 4, //執(zhí)行動畫回路,前提是設(shè)置動畫無限重復(fù)
UIViewAnimationOptionOverrideInheritedDuration = 1 << 5, //忽略外層動畫嵌套的執(zhí)行時間
UIViewAnimationOptionOverrideInheritedCurve = 1 << 6, //忽略外層動畫嵌套的時間變化曲線
UIViewAnimationOptionAllowAnimatedContent = 1 << 7, //通過改變屬性和重繪實(shí)現(xiàn)動畫效果，如果key沒有提交動畫將使用快照
UIViewAnimationOptionShowHideTransitionViews = 1 << 8, //用顯隱的方式替代添加移除圖層的動畫效果
UIViewAnimationOptionOverrideInheritedOptions = 1 << 9, //忽略嵌套繼承的?選項(xiàng)
UIViewAnimationOptionCurveEaseInOut = 0 << 16,//時間曲線函數(shù)粗蔚，由慢到快
UIViewAnimationOptionCurveEaseIn = 1 << 16, //時間曲線函數(shù)尝偎，由慢到特別快
UIViewAnimationOptionCurveEaseOut = 2 << 16, //時間曲線函數(shù)，由快到慢
UIViewAnimationOptionCurveLinear = 3 << 16,//時間曲線函數(shù)鹏控，勻速
UIViewAnimationOptionTransitionNone = 0 << 20, //無轉(zhuǎn)場動畫
UIViewAnimationOptionTransitionFlipFromLeft = 1 << 20,//轉(zhuǎn)場從左翻轉(zhuǎn)
UIViewAnimationOptionTransitionFlipFromRight = 2 << 20, //轉(zhuǎn)場從右翻轉(zhuǎn)
UIViewAnimationOptionTransitionCurlUp = 3 << 20,//上卷轉(zhuǎn)場
UIViewAnimationOptionTransitionCurlDown = 4 << 20,//下卷轉(zhuǎn)場
UIViewAnimationOptionTransitionCrossDissolve = 5 << 20,//轉(zhuǎn)場交叉消失
UIViewAnimationOptionTransitionFlipFromTop = 6 << 20,//轉(zhuǎn)場從上翻轉(zhuǎn)
UIViewAnimationOptionTransitionFlipFromBottom = 7 << 20,//轉(zhuǎn)場從下翻轉(zhuǎn)
} NS_ENUM_AVAILABLE_IOS(4_0);
