ReactiveCocoa的實際應用

1.監(jiān)聽方法執(zhí)行

• 方法：rac_signalForSelector

[[v rac_signalForSelector:@selector(touchesBegan:withEvent:)] subscribeNext:^(id  _Nullable x) {
    NSLog(@"點擊了我");
 }];

• 這個方法是創(chuàng)建對象中一定會調用的，所以在此方法中可以監(jiān)聽各個系統(tǒng)方法的執(zhí)行，換了一種方式來寫各個系統(tǒng)方法

+ (instancetype)allocWithZone:(struct _NSZone *)zone {
    ViewController *vc = [super allocWithZone:zone];
    // ViewDidLoad
    [[vc rac_signalForSelector:@selector(viewDidLoad)] subscribeNext:^(id  _Nullable x) {
        NSLog(@"ViewDidLoad");
    }];
    // ViewWillAppear
    [[vc rac_signalForSelector:@selector(viewWillAppear:)] subscribeNext:^(id  _Nullable x) {
        NSLog(@"ViewWillAppear");
    }];
    return vc;
}

2.監(jiān)聽按鈕點擊

• 方法：rac_signalForControlEvents

[[_button rac_signalForControlEvents:UIControlEventTouchDown] subscribeNext:^(id x) {
}];

3.監(jiān)聽文字的改變 ：(替代textField的代理)

• 方法：rac_textSignal

[_passWordTextField.rac_textSignal subscribeNext:^(id x) {
    _passWordLabel.text = x;
}];

• 方法：宏定義 RAC() 信號綁定

RAC(_passWordLabel, text) = _passWordTextField.rac_textSignal;

• 錯誤示范

//這樣并不能獲取textField的文字信號，獲取的是textField本身的信號，寫法錯誤
[[_passWordTextField rac_signalForControlEvents:UIControlEventValueChanged] subscribeNext:^(id x) {
    NSLog(@"%@", x);
    _passWordLabel.text = x; 
}];

4.代替KVO

• 方法：rac_valuesForKeyPath:@keypath(self, age) observer:self

    //方法默認監(jiān)聽新值和舊值
    [[self rac_valuesForKeyPath:@keypath(self, age) observer:self] subscribeNext:^(id x) {
        NSLog(@"0 - age = %d", self.age);
    }];

• 方法：rac_valuesAndChangesForKeyPath:@"age" options:NSKeyValueObservingOptionNew observer:self

    //按照選項監(jiān)聽新值或是舊值
    [[self rac_valuesAndChangesForKeyPath:@"age" options:NSKeyValueObservingOptionNew observer:self] subscribeNext:^(id x) {
        NSLog(@"1 - age = %d", self.age);
    }];

• 方法：rac_observeKeyPath:@"age" options:NSKeyValueObservingOptionNew observer:self block:

    //按照選項監(jiān)聽新值或是舊值
    [self rac_observeKeyPath:@"age" options:NSKeyValueObservingOptionNew observer:self block:^(id value, NSDictionary *change, BOOL causedByDealloc, BOOL affectedOnlyLastComponent) {
        NSLog(@"2 - age = %d", self.age);
    }];

• 方法：宏定義RACObserve()

//方法默認監(jiān)聽新值和舊值
[RACObserve(self, age) subscribeNext:^(id x) {
    NSLog(@"3 - age = %d", self.age);
}];

5.代替通知

• 方法：rac_addObserverForName

//不需要手動管理（移除）觀察者
[[[NSNotificationCenter defaultCenter] rac_addObserverForName:@"Note" object:nil] subscribeNext:^(id x) {
    NSLog(@"%@", x);
}];
[[NSNotificationCenter defaultCenter] postNotificationName:@"Note" object:nil];

6.當某幾個信號執(zhí)行完畢再去調用一個方法（rac_liftSelector）

• 注意：有幾個信號就必須有幾個參數遥巴，參數就是訂閱者發(fā)出的數據

    // 創(chuàng)建請求最熱數據信號
    RACSignal *hotSignal = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
        // 請求最熱數據
        [subscriber sendNext:@"最熱數據"];
        return nil;
    }];
    // 創(chuàng)建請求最新數據信號
    RACSignal *newSignal = [RACSignal createSignal:^RACDisposable * _Nullable(id<RACSubscriber>  _Nonnull subscriber) {
        // 請求最新的數據
        [subscriber sendNext:@"最新數據"];
        return nil;
    }];
    // Selector:當數組所有信號都發(fā)送next之后調用
    [self rac_liftSelector:@selector(updateUIWithHot:new:) withSignalsFromArray:@[hotSignal,newSignal]];