objective-c - NS_OPTIONS 个匹配项

Question

我正在尝试实现以下 typedef

typedef NS_OPTIONS (NSInteger, MyCellCorners) {
    MyCellCornerTopLeft,
    MyCellCornerTopRight,
    MyCellCornerBottomLeft,
    MyCellCornerBottomRight,
};

并正确地赋值

MyCellCorners cellCorners = (MyCellCornerTopLeft | MyCellCornerTopRight);

绘制单元格时，如何检查哪些选项匹配，以便正确绘制。

Answer 1

使用位掩码:

typedef NS_OPTIONS (NSInteger, MyCellCorners) {
    MyCellCornerTopLeft = 1 << 0,
    MyCellCornerTopRight = 1 << 1,
    MyCellCornerBottomLeft = 1 << 2,
    MyCellCornerBottomRight = 1 << 3,
};

MyCellCorners cellCorners = MyCellCornerTopLeft | MyCellCornerTopRight;

if (cellCorners & MyCellCornerTopLeft) {
    // top left corner set
}

if (etc...) {

}