RacChannel ---RacChannelTerminal+++UIControl
RacKVOChannel ------RACChannelTo
RacObserve -------RacDelegateProxy
1, RACKVOChannel
双向绑定+继承于RACChannel
代理人模式；实现KVO；
底层还是依赖于RACKVO
[RACKVOProxy.sharedProxy addObserver:self forContext:(__bridge void *)self];
[strongTarget addObserver:RACKVOProxy.sharedProxy forKeyPath:self.keyPath options:options context:(__bridge void *)self];
RACChannelTo
[[RACKVOChannel alloc] initWithTarget:(TARGET) keyPath:@keypath(TARGET, KEYPATH) nilValue:(NILVALUE)][@keypath(RACKVOChannel.new, followingTerminal)]
管道------ A[0] = 111; ///实现中括号下标操作符
- (RACChannelTerminal *)objectForKeyedSubscript:(NSString *)key {
NSCParameterAssert(key != nil);
RACChannelTerminal *terminal = [self valueForKey:key];
NSCAssert([terminal isKindOfClass:RACChannelTerminal.class], @"Key \"%@\" does not identify a channel terminal", key);
return terminal;
}
- (void)setObject:(RACChannelTerminal *)otherTerminal forKeyedSubscript:(NSString *)key {
NSCParameterAssert(otherTerminal != nil);
RACChannelTerminal *selfTerminal = [self objectForKeyedSubscript:key];
[otherTerminal subscribe:selfTerminal];
[[selfTerminal skip:1] subscribe:otherTerminal];
}
2,
使用KVC实现+ RACChannel
- (RACChannelTerminal *)rac_channelForControlEvents:(UIControlEvents)controlEvents key:(NSString *)key nilValue:(nullable id)nilValue;
[[self
rac_liftSelector:@selector(valueForKey:) withSignals:eventSignal, nil]
subscribe:channel.followingTerminal];
[self rac_liftSelector:@selector(setValue:forKey:) withSignals:valuesSignal, [RACSignal return:key], nil];
