iOS 开发之 ReactiveCocoa(进阶)
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Map : 映射
UITextField *textField =[[UITextField alloc]initWithFrame:CGRectMake(100, 100, 100, 40)];
textField.backgroundColor =[UIColor redColor];
[self.view addSubview:textField];
[[textField.rac_textSignal map:^id(NSString * value) {
return @(value.length);
}] subscribeNext:^(NSNumber * x) {
NSLog(@"%@",x);
}];
输入Ricky:
结果:
filter: 过滤
//只有当text.length>3的时候才会订阅改消息
[[textField.rac_textSignal filter:^BOOL(NSString * text) {
return text.length>3;
}] subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
同样输入Ricky结果就是:
delay:延时
//延时2秒发送消息
RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
[subscriber sendNext:@"Ricky"];
[subscriber sendCompleted];
return nil;
}] delay:2];
[signal subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
startWith:在发送消息之前,先发送一个消息
RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
[subscriber sendNext:@"Ricky"];
[subscriber sendCompleted];
return nil;
}] startWith:@"RAC"];
[signal subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
timeout :超时
//设置超时时间为2秒,当超过2秒还没有发送消息的时候,就不会发送了
RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
[[RACScheduler mainThreadScheduler] afterDelay:3 schedule:^{
[subscriber sendNext:@"Ricky"];
[subscriber sendCompleted];
}];
return nil;
}] timeout:2 onScheduler:[RACScheduler mainThreadScheduler]];
[signal subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
take :发送多个消息的时候,取最前面的几条
RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
[subscriber sendNext:@"Ricky1"];
[subscriber sendNext:@"Ricky2"];
[subscriber sendNext:@"Ricky3"];
[subscriber sendNext:@"Ricky4"];
[subscriber sendCompleted];
return nil;
}] take:2];
[signal subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
takelast :发送多个消息的时候,取最后面的几条
RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
[subscriber sendNext:@"Ricky1"];
[subscriber sendNext:@"Ricky2"];
[subscriber sendNext:@"Ricky3"];
[subscriber sendNext:@"Ricky4"];
[subscriber sendCompleted];
return nil;
}] takeLast:3];
[signal subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
takeUntil: RACSignal (发送在takeUntil后面的信号完成前的消息)
// RAC这个消息是2秒后完成,所以Ricky1 Ricky2这两个消息是可以发送到 而3秒后的Ricky3 Ricky4就不会发送.
RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
[subscriber sendNext:@"Ricky1"];
[subscriber sendNext:@"Ricky2"];
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[subscriber sendNext:@"Ricky3"];
[subscriber sendNext:@"Ricky4"];
[subscriber sendCompleted];
});
[subscriber sendCompleted];
return nil;
}] takeUntil:[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[subscriber sendNext:@"RAC"];
[subscriber sendCompleted];
});
return nil;
}]];
[signal subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
takeWhileBlock :当takeWhileBlock返回YES的时候发送消息
RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
[subscriber sendNext:@"Ricky1"];
[subscriber sendNext:@"Ricky2"];
[subscriber sendNext:@"Ricky3"];
[subscriber sendNext:@"Ricky4"];
[subscriber sendCompleted];
return nil;
}] takeWhileBlock:^BOOL(id x) {
return YES;
}];
[signal subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
skip: 跳过
//跳过前2次
RACSignal *signal = [[RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
[subscriber sendNext:@"Ricky1"];
[subscriber sendNext:@"Ricky2"];
[subscriber sendNext:@"Ricky3"];
[subscriber sendNext:@"Ricky4"];
[subscriber sendCompleted];
return nil;
}] skip:2];
[signal subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
skipWhileBlcok 和 skipUntilBlcok
-
skipWhileBlcok:当Block返回YES的时候跳过,返回No的时候发送.
-
skipUntilBlcok: skipUntilBlcok和skipWhileBlcok相反,当Block返回NO的时候跳
-
过,返回YES的时候发送.
结合及时搜索优化
当我们在做及时搜索的时候,例如在UITextField中输入搜索内容,每当我们输入一个字符的时候当会请求服务器,无形中给服务器带来了很大的压力
UITextField *textField =[[UITextField alloc]initWithFrame:CGRectMake(100, 100, 100, 40)];
textField.backgroundColor =[UIColor redColor];
[self.view addSubview:textField];
[textField.rac_textSignal subscribeNext:^(NSString * text) {
NSLog(@"request--- %@",text);
}];
-
优化请求时间间隔:throttle(节流)
throttle:设置一个间隔时间,当两次信号之间的时间差下于这个时间就不会发送请求
[[textField.rac_textSignal throttle:0.3] subscribeNext:^(NSString * text) {
NSLog(@"request--- %@",text);
}];
-
distinctUntilChanged: 优化请求字符一样的时候(当后一个请求和前一个请求一样的时候,就可以不用请求)
[[[textField.rac_textSignal throttle:0.3]distinctUntilChanged]
subscribeNext:^(NSString * text) {
NSLog(@"request--- %@",text);
}];
-
ignore :忽略某些 例如上面的空字符
[[[[textField.rac_textSignal throttle:0.3]distinctUntilChanged] ignore:@"" ]
subscribeNext:^(NSString * text) {
NSLog(@"request--- %@",text);
}];
-
switchToLatest :当你请求数据的时候,网络会有延迟,数据还没有返回回来,这时候你发送了新的请求,则我们取消前一次的请求,只发送最新的请求.
[[[[[[textField.rac_textSignal throttle:0.3]distinctUntilChanged] ignore:@"" ] map:^id(id value) {
return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
[subscriber sendNext:@"Request --- ricky"];
return nil;
}];
}] switchToLatest]
subscribeNext:^(NSString * text) {
NSLog(@"request--- %@",text);
}];
多个信号处理
RACSignal *singalA = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[subscriber sendNext:@"singalA"];
[subscriber sendCompleted];
});
return nil;
}];
RACSignal *singalB = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
[subscriber sendNext:@"singalB"];
[subscriber sendCompleted];
});
return nil;
}];
merge: 同时订阅2个信号
[[singalA merge:singalB] subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
singalA延迟2秒,singalB延迟5秒,她们相差了3秒.说明他们是同时发送的
concat
singalA完成后 才会订阅singalB 有点像串行队列 A失败了 B就不会被订阅
[[singalA concat:singalB] subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
singalA延迟2秒,singalB延迟5秒,她们相差了5秒.说明A发送完,B才发送的.
zipWith和combineLatest:每个信号都至少要发送一次才可以被订阅.
[[singalA zipWith:singalB] subscribeNext:^(RACTuple * tuple) {
NSLog(@"%@",tuple);
}];
[[RACSignal combineLatest:@[singalA,singalB]] subscribeNext:^(RACTuple * tuple) {
NSLog(@"%@",tuple);
}];
RAC中的宏(结合例子)
-
UIButton中没有setbackgroundColor forstatus这个方法,使用RAC很简单实现
UIButton *button =[UIButton buttonWithType:UIButtonTypeCustom];
button.frame = CGRectMake(100, 100, 100, 100);
button.backgroundColor = [UIColor yellowColor];
[self.view addSubview:button];
RAC(button,backgroundColor) = [RACObserve(button, selected) map:^id(NSNumber * selected) {
return [selected boolValue]?[UIColor yellowColor]:[UIColor redColor];
}];
[[button rac_signalForControlEvents:UIControlEventTouchUpInside] subscribeNext:^(UIButton * x) {
x.selected = !x.selected;
}];
-
RAC快速实现秒表
UILabel *lab =[[UILabel alloc]initWithFrame:CGRectMake(100, 100, 200, 50)];
lab.backgroundColor =[UIColor cyanColor];
[self.view addSubview:lab];
RAC(lab,text) = [[RACSignal interval:1 onScheduler:[RACScheduler mainThreadScheduler]] map:^id(NSData * value) {
return value.description;
}];
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