iOS ReactiveCocoa

一、ReactiveCocoa简介

ReactiveCocoa框架(简称RAC)是Github上的一个开源项目，是一个将函数响应式编程范例带入Object-C的开源库。iOS开发中的事件包括：Target、Delegate、KVO、通知、时钟、网络异步回调。ReactiveCocoa ，就是用信号接管了iOS 中的所有事件；也就意味着，用一种统一的方式来处理iOS中的所有事件，解决了各种分散的事件处理方式。

二、ReactiveCocoa的使用

2.1 KVO监听

注意，RAC 的信号一旦注册不会主动释放

只要在 block 中包含有 self. 一定会出现强引用* 需要使用 @weakify(self) / @strongify(self) 组合使用解除强引用

#import "ViewController.h"
#import <ReactiveCocoa/ReactiveCocoa.h>

@interface ViewController ()

@property (nonatomic, assign) NSInteger num;
@property (nonatomic, strong) UILabel *label;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(20, 50, self.view.frame.size.width-40,  35)];
    [button setTitle:@"测试" forState:UIControlStateNormal];
    [button setBackgroundColor:[UIColor orangeColor]];
    [button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
    [button addTarget:self action:@selector(buttonClick) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];

    _label = [[UILabel alloc] initWithFrame:CGRectMake(10, 100, self.view.frame.size.width-20, 30)];
    [self.view addSubview:_label];

    [self testKVO];
}

- (void)buttonClick
{
    if (self.num < 10) {
        self.num ++;
    }
}

#pragma mark - KVO 监听
- (void)testKVO
{
    @weakify(self)
    [RACObserve(self, self.num) subscribeNext:^(id x) {
        @strongify(self)
        self.label.text = [NSString stringWithFormat:@"当前num的值为：%ld", (long)self.num];
    }];
}

2.2 文本输入框事件监听

- (void)demoTextField {

    @weakify(self);
    [[self.nameText rac_textSignal]
     subscribeNext:^(id x) {
         @strongify(self);
         NSLog(@"%@",x);
         self.person.name = x;
     }];
}

2.3 文本框组合信号

- (void)textFileCombination {

    id signals = @[[self.nameText rac_textSignal],[self.passWordText rac_textSignal]];

    @weakify(self);
    [[RACSignal
      combineLatest:signals]
      subscribeNext:^(RACTuple *x) {

          @strongify(self);
          NSString *name = [x first];
          NSString *password = [x second];

          if (name.length > 0 && password.length > 0) {

              self.loginButton.enabled = YES;
              self.person.name = name;
              self.person.password = password;

          } else  {
              self.loginButton.enabled = NO;

          }
      }];

}

2.4 按钮监听

#pragma -mark 按钮监听

- (void)buttonDemo {
    @weakify(self);
    [[self.loginButton rac_signalForControlEvents:UIControlEventTouchUpInside]
       subscribeNext:^(id x) {
           @strongify(self);
           NSLog(@"person.name:  %@    person.password:  %@",self.person.name,self.person.password);
       }
     ];
}

2.5 代理方法

#pragma -mark 代理方法
/**
 * 5、验证此函：nameText的输入字符时，输入回撤或者点击键盘的回车键使passWordText变为第一响应者（即输入光标移动到passWordText处）
 */
- (void)delegateDemo {

    @weakify(self)
    // 1. 定义代理
    self.proxy = [[RACDelegateProxy alloc] initWithProtocol:@protocol(UITextFieldDelegate)];
    // 2. 代理去注册文本框的监听方法
    [[self.proxy rac_signalForSelector:@selector(textFieldShouldReturn:)]
     subscribeNext:^(id x) {
         @strongify(self)
         if (self.nameText.hasText) {
             [self.passWordText becomeFirstResponder];
         }
     }];
    self.nameText.delegate = (id<UITextFieldDelegate>)self.proxy;
}

2.6 通知

#pragma -mark 通知
/**
 * 验证此函数：点击textFile时，系统键盘会发送通知，打印出通知的内容
 */
- (void)notificationDemo {
    [[[NSNotificationCenter defaultCenter] rac_addObserverForName:UIKeyboardWillChangeFrameNotification object:nil]
        subscribeNext:^(id x) {
            NSLog(@"notificationDemo : %@", x);
        }
     ];
}