RAC+MVVM

MVVM:使用MVVM模式将网络请求以及数据处理放到VM中,主要减轻控制器的负担,使用RAC中的RACCommand发送网络请求.

M:模型

#import <Foundation/Foundation.h>

@interface Books : NSObject

@property (nonatomic, strong) NSString *subtitle;
@property (nonatomic, strong) NSString *title;
@property (nonatomic, strong) NSString *image;

+ (instancetype)bookWithDict:(NSDictionary *)dict;
@end

#import "Books.h"

@implementation Books
+ (instancetype)bookWithDict:(NSDictionary *)dict
{
    Books *book = [[Books alloc] init];
    
    book.title = dict[@"title"];
    book.image = dict[@"image"];
    book.subtitle = dict[@"subtitle"];
    return book;
}

@end

V:视图+控制器

- (void)viewDidLoad {
    [super viewDidLoad];

    UITableView *tableView = [[UITableView alloc] initWithFrame:self.view.bounds style:UITableViewStylePlain];
    tableView.delegate = self.requestModel;
    tableView.dataSource = self.requestModel;
    [self.view addSubview:tableView];
    self.requestModel.tableView = tableView;
    
    //执行请求
    [self.requestModel.requestCMD execute:nil];
    
}

VM:视图模型

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#import "ReactiveCocoa.h"

@interface RequestViewModel : NSObject<UITableViewDataSource,UITableViewDelegate>

@property (nonatomic, weak) UITableView *tableView;
/** 请求命令*/
@property (nonatomic, strong) RACCommand *requestCMD;
//模型数组
@property (nonatomic, strong, readonly) NSArray *models;

@end

#import "RequestViewModel.h"
#import "AFNetworking.h"
#import "Books.h"

@implementation RequestViewModel

- (instancetype)init {
    if (self == [super init]) {
        [self initialBind];
    }
    return self;
}

- (void)initialBind {
    _requestCMD = [[RACCommand alloc] initWithSignalBlock:^RACSignal *(id input) {
        RACSignal *signal = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
            AFHTTPSessionManager *sessionMgr = [AFHTTPSessionManager manager];
            [sessionMgr GET:@"https://api.douban.com/v2/book/search" parameters:@{@"q":@"美女"} progress:^(NSProgress * _Nonnull downloadProgress) {
            } success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {

                //把数据用信号传递出去
                [subscriber sendNext:responseObject];
                [subscriber sendCompleted];
            } failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
                
            }];
            return nil;
        }];

        //再返回数据信号的时候,把数据中的字典映射成模型信号,传递出去
        return [signal map:^id(NSDictionary *value) {
            NSMutableArray *dicArray = value[@"books"];
            
            NSArray *model = [[dicArray.rac_sequence map:^id(NSDictionary *value) {
                return [Books bookWithDict:value];
            }] array];
            return model;
        }] ;
    }];

    //获取请求的数据
    [_requestCMD.executionSignals.switchToLatest subscribeNext:^(id x) {
        
        //赋值新数据
        _models = x;
        [self.tableView reloadData];
    }];
    
}

#pragma mark - UITableViewDelegate

#pragma mark - Table view data source
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    return 60;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return self.models.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cell"];
    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"cell"];
    }
    
    Books *book = self.models[indexPath.row];
    cell.textLabel.text = book.title;
    cell.detailTextLabel.text = book.subtitle;
    
    return cell;
}
@end

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