ReactiveCocoa使用详解

ReactiveCocoa是基于响应式编程的实践，使用起来很方便，下面将讲解详细使用。

1.监听对象的成员变量变化，当成员变量值被改变时，触发做一些事情.A)普通属性@property(nonatomic,copy) NSString *changeinput;[RACObserve(self, changeinput) subscribeNext:^(id x) {NSLog(@"成员变量 changeinput 被修改成了：%@", x);}];当在其他地方修改了changeinput的属性值，将会调用。B)如何监听控件的值变化，[[self.textfiled.rac_textSignalfilter:^(NSString *str) {if (str.integerValue > 30) {return YES;} else {return NO;}}]subscribeNext:^(NSString *str) {NSLog(@"textfield 控件变化了：%@",str);}];2. 属性绑定，转换数据流A)//直接绑定RAC(self.loginButton,enabled) = RACObserve(self,isCanLogin);;//需要转换数据流，让输入和alpha绑定，当输入为12时，透明度为1.0 否则是0.5RACSignal *changeSignal = RACObserve(self,changeinput);RAC(self.loginButton, alpha) = [changeSignalmap:^id(NSString *str) {return [str isEqualToString:@"12"] ? @1.0 : @0.5;}];B)两个输入，按钮之间的绑定关系，当输入长度大于5时，按钮可点击RACSignal *validUsernameSignal = [self.textfiled.rac_textSignal map:^id(NSString *text) {return @(text.length >5);}];RACSignal *validPasswordSignal = [self.passwordTextfield.rac_textSignal map:^id(NSString *text) {return @(text.length >5);}];RACSignal *signUpActiveSignal = [RACSignal combineLatest:@[validUsernameSignal, validPasswordSignal]reduce:^id(NSNumber *usernameValid, NSNumber *passwordValid){return @([usernameValid boolValue] && [passwordValid boolValue]);}];[signUpActiveSignal subscribeNext:^(NSNumber *signupActive) {self.loginButton.enabled = [signupActive boolValue];}];3.两个控件之间的绑定关系，如输入框输入，label显示输入结果RAC(self.outputLabel,text) = self.textfiled.rac_textSignal;或者也可以和一个属性值绑定，当changeinput改变时，outputLabel也会发生改变，RAC(self.outputLabel, text) = RACObserve(self, changeinput);4.事件监听- (void)eventListener{RACSignal *buttonSignal = [self.signalButton rac_signalForControlEvents:UIControlEventTouchUpInside];[buttonSignal subscribeNext:^(id x) {NSLog(@"buttonSignal %@",buttonSignal);}];RACSignal *textChange = [self.passwordTextfield rac_textSignal];[textChange subscribeNext:^(NSString *textfield){NSLog(@"textfield %@", textfield);}];RACSignal *viewAppeared = [self rac_signalForSelector:@selector(viewDidAppear:)];[viewAppeared subscribeNext:^(id x) {NSLog(@"viewDidAppear %@", x);}];}5.其它的一些用法如，A)添加观察者[[[NSNotificationCenter defaultCenter] rac_addObserverForName:@"MyNotification" object:nil] subscribeNext:^(NSNotification *notification) {NSLog(@"Notification Received");}];B)object的dealloc被触发时，执行的一段代码，这样很方便吧　　NSArray *array = @[@"foo"];[[array rac_willDeallocSignal] subscribeCompleted:^　　{　　NSLog(@"will dealloc");}];array = nil;