ReactiveCocoa的使用

1.ReactiveCocoa(简称RAC),是GitHub上开源的一个应用于iOS和OS X开发的一个新框架.RAC具有函数式编程和响应者编程的特性

RAC是一套super重量级函数响应编程开源框架，它可以帮助我们简单粗暴的处理事件！！！

2.在实际开发中的使用

2.1UIButton

[[_btn rac_signalForControlEvents:UIControlEventTouchUpInside]subscribeNext:^(__kindof UIControl * _Nullable x) {
        NSLog(@"%@",x);
        //在这里执行_btn点击后的code
    }];

2.2UITextField

[[_textField rac_textSignal]subscribeNext:^(NSString * _Nullable x) {
        NSLog(@"%@",x);
        //_textField.text内容改变后的block回调
    }];

2.3通知

[[[NSNotificationCenter defaultCenter]rac_addObserverForName:UIKeyboardDidShowNotification object:nil]subscribeNext:^(NSNotification * _Nullable x) {
        NSLog(@"%@",x.userInfo);
    }];

2.4Timer定时器

使用RAC来实现定时器，能够完美解决循环引用，内存不释放的问题，

//定时器
    self.timerDisposable = [[RACSignal interval:2.0 onScheduler:[RACScheduler mainThreadScheduler]]subscribeNext:^(NSDate * _Nullable x) {
        NSLog(@"我是定时器");
    }];
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(50 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        //在合适的位置调用，释放定时器
        [self.timerDisposable dispose];
    });

2.5KVO

2.5.1监听对象的成员变量

@interface Person:NSObject
@property(nonatomic,strong) NSString * name;
@end

@implementation Person

@end

@interface ViewController ()
@property(nonatomic,strong) Person * person;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    _person = [[Person alloc]init];
    _person.name = @"小王";
    //无需进行移除监听通知的操作，返回的RACDisposable对象会帮我们做这些操作
    [_person rac_observeKeyPath:@"name" options:NSKeyValueObservingOptionNew observer:nil block:^(id value, NSDictionary *change, BOOL causedByDealloc, BOOL affectedOnlyLastComponent) {
        NSLog(@"name修改了");
    }];
    
}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    _person.name = @"小李";
    NSLog(@"%@",_person.name);
}

2.5.2监听self的成员变量

 //监听self.changeStr值得变化
    [RACObserve(self, changeStr)subscribeNext:^(id  _Nullable x) {
        NSLog(@"%@",x);
    }];

2.6 合并信号

[[RACSignal combineLatest:@[[_textField rac_textSignal],[_passwordTextField rac_textSignal]] reduce:^id _Nonnull(NSString *name,NSString*password){
        return [NSString stringWithFormat:@"%@+%@",name,password];
    }]subscribeNext:^(id  _Nullable x) {
        NSLog(@"%@",x); // x = name+password
    }];

2.7 过滤

- (void)viewDidLoad {
    [super viewDidLoad];
    self.username = @"liuguanhua";
    //过滤
    //-filter 只有当block返回YES时才会创建一个新的RACSignal发送一个新值
    //只有当名字的开头为"liu"时才打印
    [[RACObserve(self, username)filter:^BOOL(id  _Nullable value) {
        return [value hasPrefix:@"liu"];
    }]subscribeNext:^(id  _Nullable newName) {
        NSLog(@"%@",newName);
    }];
}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    self.username = @"liuxiaoyun";
}

2.8 信号聚合

self.btn的enabled属性可以由self.textField.text以及self.passwordTextField的内容长度决定。
当username和password的长度都>=6时，返回YES.

RAC(self.btn, enabled) = [RACSignal
     combineLatest:@[self.textField.rac_textSignal,self.passwordTextField.rac_textSignal]
     reduce:^(NSString *name, NSString *password) {
         NSLog(@"%@,%@",name,password);
         return @(name.length>=6 && password.length>=6); //需要返回对象
     }];

2.9 序列

//序列
    NSArray *array = @[@"a",@"b",@"ab",@"agh",@"gha",@"rta",@"sda",@"asa",@"vba",@"nma",@(14),@(YES)];
    [array.rac_sequence.signal subscribeNext:^(id  _Nullable x) {
        NSLog(@"%@",x);
    }];
    
    NSDictionary *dict = @{
                           @"name":@"lgh",
                           @"age":@(14)
                           };
    [dict.rac_sequence.signal subscribeNext:^(id  _Nullable x) {
        NSLog(@"%@",x);
    }];

2.10协议

//协议
    [[self rac_signalForSelector:@selector(textFieldDidEndEditing:) fromProtocol:@protocol(UITextFieldDelegate)]subscribeNext:^(RACTuple * _Nullable x) {
        NSLog(@"protocol:%@",x);
    }];
    self.textField.delegate = self;

2.11手势

//手势
    UITapGestureRecognizer *reg = [[UITapGestureRecognizer alloc]init];
    self.label.userInteractionEnabled = YES;
    [self.label addGestureRecognizer:reg];
    [[reg rac_gestureSignal]subscribeNext:^(__kindof UIGestureRecognizer * _Nullable x) {
        NSLog(@"UIGestureRecognizer: %@",x);
    }];