简介：本文主要对RAC常见使用方法及易混淆的概念和注意事项进行汇总，方便后续查询和学习。原文请参考：《ReactiveCocoa 概述》《zwcshy/RAC》常见问题请参考《iOS RAC常见问题汇总》
1.代替代理
//代理
[[self rac_signalForSelector:@selector(tableView:didSelectRowAtIndexPath:) fromProtocol:@protocol(UITableViewDelegate)] subscribeNext:^(id x) {
}];
2.监听事件
按钮点击
[[self.button rac_signalForControlEvents:UIControlEventTouchUpInside] subscribeNext:^(id x) {
}];
文本内容变化
[[self.textField rac_textSignal] subscribeNext:^(NSString * _Nullable x) {
}];
手势事件
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]init];
[tap.rac_gestureSignal subscribeNext:^(id x) {
}];
3.通知
[[[NSNotificationCenter defaultCenter] rac_addObserverForName:@"name" object:nil] subscribeNext:^(id x) {
}];
4.KVO
//方法1
[[self rac_valuesAndChangesForKeyPath:@"title" options:NSKeyValueObservingOptionNew observer:nil] subscribeNext:^(id x) {
}];
//方法2
[[self rac_valuesForKeyPath:@"title" observer:nil] subscribeNext:^(id x) {
}];
//方法3
[RACObserve(self, title) subscribeNext:^(id x) {
}];
5.定时器
//定时器
RACDisposable * disposable = [[RACSignal interval:1 onScheduler:[RACScheduler scheduler]] subscribeNext:^(id x) {
}];
//释放定时器
[disposable dispose];
6.集合遍历RACSequence
数组遍历
//默认在子线程中遍历
NSArray *numbers = @[@"1",@"2",@"3",@"4"];
[numbers.rac_sequence.signal subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
//放在主线程中遍历
[[numbers.rac_sequence.signal deliverOn:[RACScheduler mainThreadScheduler]] subscribeNext:^(id _Nullable x) {
}];
字典遍历
NSDictionary * dic = @{
@"1":@"1111",
@"2":@"2222",
@"3":@"3333",
@"4":@"4444"
};
[dic.rac_sequence.signal subscribeNext:^(id x) {
RACTupleUnpack(NSString * key,NSObject * value) = x;
NSLog(@"key=%@,value=%@",key,value);
}];
字符串遍历
NSString *text = @"123456789";
[text.rac_sequence.signal subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
7.映射Map（生成新的值）flattenMap（生成新的信号）
map（生成新的值）
NSArray * newNumbers = [numbers.rac_sequence map:^id(id value) {
return [NSString stringWithFormat:@"numbers: %@",value];
}].array;
flattenMap（生成新的信号）
// 创建信号
RACSubject *subject = [RACSubject subject];
// 绑定信号
RACSignal *bindSignal = [subject flattenMap:^RACStream *(id value) {
// value: 就是源信号发送的内容
// 返回信号用来包装成修改内容的值
return [RACReturnSignal return:value];
}];
// flattenMap中返回的是什么信号，订阅的就是什么信号(那么，x的值等于value的值，如果我们操纵value的值那么x也会随之而变)
// 订阅信号
[bindSignal subscribeNext:^(id x) {
NSLog(@"%@", x);
}];
// 发送数据
[subject sendNext:@"123"];
8.延时执行
throttle:延时调用block(subscribeNext)
[[[self.button rac_signalForControlEvents:UIControlEventTouchUpInside] throttle:5] subscribeNext:^(id x) {
}];
delay:延迟调用
[[[self.button rac_signalForControlEvents:UIControlEventTouchUpInside] delay:5] subscribeNext:^(id x) {
}];
timeout:超时后则不调用block
[[self.signal timeout:5 onScheduler:[RACScheduler scheduler]] subscribeNext:^(id x) {
}];
延时执行
[[RACScheduler scheduler] after:[NSDate dateWithTimeIntervalSinceNow:3] schedule:^{
}];
9.过滤
filter接受满足条件的信号
[[numbers.rac_sequence.signal filter:^BOOL(id value) {
return [value integerValue] > 3;
}] subscribeNext:^(id x) {
}];
// 只有当文本框的内容长度大于5，才获取文本框里的内容
[[self.textField.rac_textSignal filter:^BOOL(id value) {
// value 源信号的内容
return [value length] > 5;
// 返回值 就是过滤条件。只有满足这个条件才能获取到内容
}] subscribeNext:^(id x) {
NSLog(@"%@", x);
}];
skip跳过几个信号
// skip:后边传入要跳过几个信号
RACSubject *subject = [RACSubject subject];
[[subject skip:2] subscribeNext:^(id x) {
NSLog(@"%@", x);
}];
[subject sendNext:@1];
[subject sendNext:@2];
[subject sendNext:@3];
distinctUntilChanged新值与旧值不一样则接收
//例子1
RACSubject *subject = [RACSubject subject];
[[subject distinctUntilChanged] subscribeNext:^(id x) {
NSLog(@"%@", x);
}];
// 发送信号
[subject sendNext:@1];
[subject sendNext:@2];
[subject sendNext:@2]; // 不会被订阅
//例子2
[[RACObserve(self, title) distinctUntilChanged] subscribeNext:^(id x) {
}];
take只拿前几个值
RACSubject *subject = [RACSubject subject];
[[subject take:2] subscribeNext:^(id x) {
NSLog(@"%@", x);
}];
// 发送信号
[subject sendNext:@1];
[subject sendNext:@2];
[subject sendNext:@3];
takeLast取最后几个值，takeLast 一定要调用sendCompleted，告诉他发送完成才能取到最后的几个值
RACSubject *subject = [RACSubject subject];
[[subject takeLast:2] subscribeNext:^(id x) {
NSLog(@"%@", x);
}];
// 发送信号
[subject sendNext:@1];
[subject sendNext:@2];
[subject sendNext:@3];
[subject sendCompleted];
takeUntil给takeUntil传的是哪个信号，那么当这个信号发送信号或sendCompleted，就不能再接受源信号的内容了
RACSubject *subject = [RACSubject subject];
RACSubject *subject2 = [RACSubject subject];
[[subject takeUntil:subject2] subscribeNext:^(id x) {
NSLog(@"%@", x);
}];
// 发送信号
[subject sendNext:@1];
[subject sendNext:@2];
[subject2 sendNext:@3]; // 1
// [subject2 sendCompleted]; // 或2
[subject sendNext:@4];
ignore:忽略一些值
ignoreValues:表示忽略所有的值
// 1.创建信号
RACSubject *subject = [RACSubject subject];
// 2.忽略一些值
RACSignal *ignoreSignal = [subject ignore:@2]; // ignoreValues:表示忽略所有的值
// 3.订阅信号
[ignoreSignal subscribeNext:^(id x) {
NSLog(@"%@", x);
}];
// 4.发送数据
[subject sendNext:@2];
10.RAC组合
combine场景：账号和密码都有值，登录按钮才可点击
//reduce里的参数一定要和combineLatest数组里的一一对应。
RACSignal *combinSignal = [RACSignal combineLatest:@[self.accountField.rac_textSignal, self.pwdField.rac_textSignal] reduce:^id(NSString *account, NSString *pwd){ NSLog(@"%@ %@", account, pwd);
return @(account.length && pwd.length);
}];
RAC(self.loginBtn, enabled) = combinSignal;
merge多个信号合并成一个信号，任何一个信号有新值就会调用
// 创建信号A
RACSubject *signalA = [RACSubject subject];
// 创建信号B
RACSubject *signalB = [RACSubject subject];
//组合信号
RACSignal *mergeSignal = [signalA merge:signalB];
// 订阅信号
[mergeSignal subscribeNext:^(id x) {
NSLog(@"%@", x);
}];
// 发送信号---交换位置则数据结果顺序也会交换
[signalB sendNext:@"下部分"];
[signalA sendNext:@"上部分"];
concat:串行执行，第一个信号必须要调用sendCompleted
// 创建信号A
RACSignal *signalA = [RACSignal createSignal:^RACDisposable *(id subscriber) {
[subscriber sendNext:@"上部分数据"];
[subscriber sendCompleted]; // 必须要调用sendCompleted方法！
return nil;
}];
// 创建信号B，
RACSignal *signalsB = [RACSignal createSignal:^RACDisposable *(id subscriber) {
[subscriber sendNext:@"下部分数据"];
return nil;
}];
// 创建组合信号
RACSignal *concatSignal = [signalA concat:signalsB];
// 订阅组合信号
[concatSignal subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
其他方法
doNext:添加额外执行代码
[[[self.button rac_signalForControlEvents:UIControlEventTouchUpInside] doNext:^(id x){
//开始loading
}] subscribeNext:^(id x){
//结束loading
}];