使用场景：同一次操作有多个选项，可以同时多选同时禁用
摘取一段定义好的iOS代码
typedef NS_OPTIONS(NSUInteger, NSKeyValueObservingOptions) {
NSKeyValueObservingOptionNew =0x01, // = 1 << 0 , 1
NSKeyValueObservingOptionOld =0x02, // = 1 << 1 , 2
NSKeyValueObservingOptionInitial NS_ENUM_AVAILABLE(10_5,2_0) =0x04, // = 1 << 2 , 4
NSKeyValueObservingOptionPrior NS_ENUM_AVAILABLE(10_5,2_0) =0x08 // = 1 << 3 , 8
};
写一个方法，需要选择两种特性来实现
- (void)chooseTwoCharacter:(NSKeyValueObservingOptions)options {
if (options == 0) {
return;
}
else if (options & NSKeyValueObservingOptionNew ==
NSKeyValueObservingOptionNew) {
NSLog(@"choose NSKeyValueObservingOptionNew");
}
else if (options & NSKeyValueObservingOptionNew ==
NSKeyValueObservingOptionOld) {
NSLog(@"choose NSKeyValueObservingOptionOld");
}
else if (options & NSKeyValueObservingOptionNew ==
NSKeyValueObservingOptionInitial) {
NSLog(@"choose NSKeyValueObservingOptionInitial");
}
else if (options & NSKeyValueObservingOptionNew ==
NSKeyValueObservingOptionPrior) {
NSLog(@"choose NSKeyValueObservingOptionPrior");
}
}
那么我们在调用的时候可以将需要选择的枚举值按位或，或者按十进制相加
<code>
NSKeyValueObservingOptions options = NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld; // 0x0011
[self chooseTwoCharacter:options];
NSKeyValueObservingOptions options2 = NSKeyValueObservingOptionNew + NSKeyValueObservingOptionOld; // 3
[self chooseTwoCharacter:options2];
</code>
