RACSignal使用基础
ReactiveCocoa的基础—-信号。信号变相来说也是一种对象，需要创建，本身不具备发送的能力
获取信号的方式
单元信号
1
2
3
4
5
| RACSignal *signal1 = [RACSignal return:@"some value"];
NSError *error;
RACSignal *signal2 = [RACSignal error:error];
RACSignal *signal3 = [RACSignal empty];
RACSignal *signal4 = [RACSignal never];
|
动态信号
源码解析：创建一个RACDynamicSignal并且保存一个didSubscribeblock，返回RACSignal对象。
注意：在创建动态信号结束的时候要sendCompleted
1
2
3
4
5
6
7
8
9
| RACSignal *signal5 = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber> _Nonnull subscriber) {
[subscriber sendNext:@1];
[subscriber sendNext:@2];
NSError *error;
[subscriber sendError:error];
[subscriber sendCompleted];
return [RACDisposable disposableWithBlock:^{
}];
}];
|
cocoa桥接
1
2
3
4
5
| UIButton *view;
RACSignal *signal6 = [view rac_signalForSelector:@selector(setFrame:)];
RACSignal *signal7 = [view rac_willDeallocSignal];
RACSignal *signal8 = [view rac_signalForControlEvents:UIControlEventTouchUpInside];
RACSignal *signal9 = RACObserve(view, backgroundColor);
|
信号变换
1
2
3
| RACSignal *signal10 = [signal1 map:^id _Nullable(id _Nullable value) {
return [value substringFromIndex:1];
}];
|
序列转换
1
2
| RACSequence *squence = [RACSequence empty];
RACSignal *signal11 = squence.signal;
|
信号的使用
订阅一个信号
源码大致顺序就是创建subscriber，调用subscriber，block回调
1
2
3
4
5
6
7
| [signal10 subscribeNext:^(id _Nullable x) {
NSLog(@"next value is %@",x);
} error:^(NSError * _Nullable error) {
NSLog(@"some error:%@",error);
} completed:^{
NSLog(@"finished success");
}];
|
绑定（常用，kvo）
1
| RAC(view,backgroundColor) = signal10;
|
cocoa桥接
1
2
3
4
|
[view rac_liftSelector:@selector(convertPoint:toView:) withSignals:signal1,signal2, nil];
[view rac_liftSelector:@selector(convertPoint:toView:) withSignalsFromArray:@[signal3,signal4]];
[view rac_liftSelector:@selector(convertPoint:toView:) withSignalOfArguments:signal5];
|
订阅过程
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
| RACSignal *signal = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber> _Nonnull subscriber) {
[subscriber sendNext:@1];
[subscriber sendNext:@2];
[subscriber sendCompleted];
return [RACDisposable disposableWithBlock:^{
NSLog(@"dispose");
}];
}];
RACDisposable *disposable = [signal subscribeNext:^(id _Nullable x) {
NSLog(@"next value is %@",x);
} error:^(NSError * _Nullable error) {
NSLog(@"some error:%@",error);
} completed:^{
NSLog(@"finished success");
}];
[disposable dispose];
|
RACSignal各种操作
对值操作
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
| RACSignal *signala = [RACSignal return:@1];
RACSignal *signalb = [signala map:^id _Nullable(NSNumber *value) {
return @(value.intValue * 2);
}];
RACSignal *signalc = [signala mapReplace:@8];
RACSignal *signald = [signala reduceEach:^id (NSNumber *a,NSNumber *b){
return @(a.intValue + b.intValue);
}];
[signala subscribeNext:^(id _Nullable x) {
NSLog(@"next %@",x);
} completed:^{
NSLog(@"compltet");
}];
|
数量操作
1
2
3
4
5
6
7
8
9
| RACSignal *signale = [signala filter:^BOOL(NSString *value) {
return value.length > 2;
}];
RACSignal *signalf = [signala take:2];
RACSignal *signalg = [signala skip:1];
RACSignal *signalh = [signala startWith:@7];
RACSignal *signali = [signala repeat];
RACSignal *signalj = [signala retry];
RACSignal *signalk = [signala retry:3];
|
副作用
1
2
3
| [signala doNext:^(id _Nullable x) {
}];
|
收集
折叠、汇聚
1
2
3
4
5
6
7
8
|
[signala aggregateWithStart:@1 reduce:^id _Nonnull(NSNumber * running, NSNumber *next) {
return @(running.intValue + next.intValue);
}];
[signala scanWithStart:@1 reduce:^id _Nullable(NSNumber * running,NSNumber * next) {
return @(running.intValue + next.intValue);
}];
|
实践操作 timer信号
1
2
3
| RACSignal *signall = [signala delay:1];
[signala throttle:2];
|
多个信号组合操作
首尾合并，第一个信号终止后拼接第二个信号
1
2
3
| RACSignal *signala = [RACSignal return:@2];
RACSignal *signalb = [RACSignal return:@5];
RACSignal *signalc = [signala concat:signalb];
|
根据时间轴合并，如果不是同一线程，signal会跳
1
2
| [signalb merge:signala];
`
|
zip 拉链 连个信号打包成tuple的形式，场景：需要a请求数据和b请求数据，此时zip两个数据的信号
1
| [signalb zipWith:signala];
|
combinelatest 两个信号互相与最新的信号组合成tuple
1
| [signalb combineLatestWith:signala];
|
sample采样 当signala收到信号的时候会在新的信号中取signalb中的信号
1
| [signalb sample:signala];
|
takeUntil 当signalb信号相应时signala截止
akeuntilreplacement 当signalb信号相应时signala截止,并且在接下来接入signalb的信号
1
| [signalb takeUntilReplacement:signala];
|
