MVVM优缺点
1:任务均摊 -- MVVM 的 View 要比 MVP 中的 View 承担的责任多。因为前者通过 ViewModel 的设置绑定来更新状态，而后者只监听 Presenter 的事件但并不会对自己有什么更新。
2:可测试性 -- ViewModel 不知道关于 View 的任何事情，这允许我们可以轻易的测试 ViewModel。同时 View 也可以被测试，但是由于属于 UIKit 的范畴，对他们的测试通常会被忽略。
3:易用性 -- 在实际开发中必须把 View 中的事件指向 Presenter 并且手动的来更新 View，如果使用绑定的话，MVVM 代码量将会小的多。
MVC视图控制器太大且难以管理，这个模式提供了一个很好的代替MVC的方案，它保证了让视图控制器的轻量性。
MVVM核心 block回调通过RAC结合进行双向绑定
MVVM结构
- M层-Model层
//
// Model.h
// 002-MVVM
//
// Created by Cooci on 2018/4/1.
// Copyright © 2018年 Cooci. All rights reserved.
//
#import <Foundation/Foundation.h>
@interface Model : NSObject
@end
//
// Model.m
// 002-MVVM
//
// Created by Cooci on 2018/4/1.
// Copyright © 2018年 Cooci. All rights reserved.
//
#import "Model.h"
@implementation Model
@end
- VM - ViewModel
//
// BaseViewModel.h
// 002-MVVM
//
// Created by Cooci on 2018/6/14.
// Copyright © 2018年 Cooci. All rights reserved.
//
#import <Foundation/Foundation.h>
typedef void(^SuccessBlock)(id data);
typedef void(^FailBlock)(id data);
@interface BaseViewModel : NSObject{
@public
NSString *name;
}
@property (nonatomic, copy) SuccessBlock successBlock;
@property (nonatomic, copy) FailBlock failBlock;
- (void)initWithBlock:(SuccessBlock)successBlock fail:(FailBlock)failBlock;
@end
//
// BaseViewModel.m
// 002-MVVM
//
// Created by Cooci on 2018/6/14.
// Copyright © 2018年 Cooci. All rights reserved.
//
#import "BaseViewModel.h"
@implementation BaseViewModel
- (void)initWithBlock:(SuccessBlock)successBlock fail:(FailBlock)failBlock{
_successBlock = successBlock;
_failBlock = failBlock;
}
@end
//
// MVVMViewModel.h
// 002-MVVM
//
// Created by Cooci on 2018/4/1.
// Copyright © 2018年 Cooci. All rights reserved.
//
#import "BaseViewModel.h"
#import <UIKit/UIKit.h>
@interface MVVMViewModel : BaseViewModel
@property (nonatomic, copy) NSString *contentKey;
@property (nonatomic, strong) NSMutableArray *dataArray;
- (void)loadData;
@end
//
// MVVMViewModel.m
// 002-MVVM
//
// Created by Cooci on 2018/4/1.
// Copyright © 2018年 Cooci. All rights reserved.
//
#import "MVVMViewModel.h"
#import <ReactiveObjC.h>
@implementation MVVMViewModel
- (instancetype)init{
if (self==[super init]) {
// [self addObserver:self forKeyPath:@"contentKey" options:(NSKeyValueObservingOptionNew) context:nil];
}
return self;
}
- (void)initWithBlock:(SuccessBlock)successBlock fail:(FailBlock)failBlock{
[super initWithBlock:successBlock fail:failBlock];
[RACObserve(self, contentKey) subscribeNext:^(id _Nullable x) {
NSArray *array = @[@"转账",@"信用卡",@"充值中心",@"蚂蚁借呗",@"电影票",@"滴滴出行",@"城市服务",@"蚂蚁森林"];
NSMutableArray *mArray = [NSMutableArray arrayWithCapacity:1];
[mArray addObjectsFromArray:array];
[mArray removeObject:x];
self.successBlock(mArray);
}];
}
- (void)loadData{
dispatch_async(dispatch_get_global_queue(0, 0), ^{
NSArray *array = @[@"转账",@"信用卡",@"充值中心",@"蚂蚁借呗",@"电影票",@"滴滴出行",@"城市服务",@"蚂蚁森林"];
// 有问题:
dispatch_async(dispatch_get_main_queue(), ^{
self.successBlock(array);
});
});
}
//#pragma mark - KVO回调
//- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context{
// NSLog(@"%@",change[NSKeyValueChangeNewKey]);
//
// NSArray *array = @[@"转账",@"信用卡",@"充值中心",@"蚂蚁借呗",@"电影票",@"滴滴出行",@"城市服务",@"蚂蚁森林"];
// NSMutableArray *mArray = [NSMutableArray arrayWithCapacity:1];
// [mArray addObjectsFromArray:array];
// [mArray removeObject:change[NSKeyValueChangeNewKey]];
//
// self.successBlock(mArray);
//}
//
//#pragma mark - dealloc
//
//- (void)dealloc{
// [self removeObserver:self forKeyPath:@"contentKey"];
//}
#pragma mark - lazy
- (NSMutableArray *)dataArray{
if (!_dataArray) {
_dataArray = [NSMutableArray arrayWithCapacity:10];
}
return _dataArray;
}
@end
- V层 View层
//
// MVVMView.h
// 002-MVVM
//
// Created by Cooci on 2018/4/1.
// Copyright © 2018年 Cooci. All rights reserved.
//
#import <UIKit/UIKit.h>
@interface MVVMView : UIView
- (void)headViewWithData:(id)data;
@end
//
// MVVMView.m
// 002-MVVM
//
// Created by Cooci on 2018/4/1.
// Copyright © 2018年 Cooci. All rights reserved.
//
#import "MVVMView.h"
#define SCREEN_WIDTH [UIScreen mainScreen].bounds.size.width
#define random(r, g, b, a) [UIColor colorWithRed:(r)/255.0 green:(g)/255.0 blue:(b)/255.0 alpha:(a)/255.0]
#define randomColor random(arc4random_uniform(256), arc4random_uniform(256), arc4random_uniform(256), arc4random_uniform(256))
@implementation MVVMView{
NSMutableArray *dataArray;
}
- (void)headViewWithData:(id)data{
NSMutableArray *dataArray = [NSMutableArray arrayWithCapacity:4];
dataArray = data;
for (int i = 0; i<dataArray.count; i++) {
int row = i % 4;
int loc = i / 4;
CGFloat btnW = SCREEN_WIDTH/4;
CGFloat btnH = 50;
CGFloat btnX = row*btnW;
CGFloat btnY = loc*btnH;
UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
[btn setTitle:dataArray[i] forState:UIControlStateNormal];
[btn setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
[btn setBackgroundColor:randomColor];
btn.frame = CGRectMake(btnX, btnY, btnW, btnH);
btn.tag = 1000+i;
[btn addTarget:self action:@selector(didClickBtn:) forControlEvents:UIControlEventTouchUpInside];
[self addSubview:btn];
}
}
#pragma mark - action
- (void)didClickBtn:(UIButton *)sender{
NSInteger tag = sender.tag - 1000;
NSLog(@"%zd",tag);
}
#pragma mark - private
/**
通过颜色获得图片
*/
- (UIImage *)createImageWithColor:(UIColor *)color {
CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [color CGColor]);
CGContextFillRect(context, rect);
UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return theImage;
}
@end
- 调用层
//
// ViewController.m
// 002-MVVM
//
// Created by Cooci on 2018/4/1.
// Copyright © 2018年 Cooci. All rights reserved.
//
#import "ViewController.h"
#import "MVVMViewModel.h"
#import "MVVMView.h"
#define SCREEN_WIDTH [UIScreen mainScreen].bounds.size.width
static NSString *const reuserId = @"reuserId";
@interface ViewController ()<UITableViewDelegate,UITableViewDataSource>
@property (nonatomic, strong) NSMutableArray *dataArray;
@property (nonatomic, strong) UITableView *tableView;
@property (nonatomic, strong) MVVMViewModel *vm;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// 双向绑定 ---> 数据 绑定 UI
// 写一次 use anywhere
// VC 作用: model VS UI
__weak typeof(self) weakSelf = self;
self.vm = [[MVVMViewModel alloc] init];
[self.vm initWithBlock:^(id data) {
NSArray *array = (NSArray *)data;
[weakSelf.dataArray removeAllObjects];
[weakSelf.dataArray addObjectsFromArray:array];
MVVMView *headView = [[MVVMView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, (array.count + 1)/4*50)];
[headView headViewWithData:array];
weakSelf.tableView.tableHeaderView = headView;
[weakSelf.tableView reloadData];
} fail:nil];
[self.view addSubview:self.tableView];
self.tableView.dataSource = self;
self.tableView.delegate = self;
}
- (IBAction)didClickReloadDataItem:(id)sender {
NSLog(@"点我刷新数据");
[self.vm loadData];
}
#pragma mark - tableViewDataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return self.dataArray.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:reuserId forIndexPath:indexPath];
cell.textLabel.text = self.dataArray[indexPath.row];
return cell;
}
#pragma mark - tableViewDelegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
[tableView deselectRowAtIndexPath:indexPath animated:YES];
self.vm.contentKey = self.dataArray[indexPath.row];
}
#pragma mark - lazy
- (NSMutableArray *)dataArray{
if (!_dataArray) {
_dataArray = [NSMutableArray arrayWithCapacity:10];
}
return _dataArray;
}
- (UITableView *)tableView{
if (!_tableView) {
_tableView = [[UITableView alloc] initWithFrame:self.view.bounds style:UITableViewStylePlain];
_tableView.backgroundColor = [UIColor whiteColor];
[_tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:reuserId];
}
return _tableView;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
MVVM亮点
- 双向绑定（UI和model）
self.vm = [[MVVMViewModel alloc] init];
[self.vm initWithBlock:^(id data) {
NSArray *array = (NSArray *)data;
[weakSelf.dataArray removeAllObjects];
[weakSelf.dataArray addObjectsFromArray:array];
MVVMView *headView = [[MVVMView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, (array.count + 1)/4*50)];
[headView headViewWithData:array];
weakSelf.tableView.tableHeaderView = headView;
[weakSelf.tableView reloadData];
} fail:nil];
- (void)initWithBlock:(SuccessBlock)successBlock fail:(FailBlock)failBlock{
[super initWithBlock:successBlock fail:failBlock];
//观察contentKey这个属性，当属性发生改变的时候
[RACObserve(self, contentKey) subscribeNext:^(id _Nullable x) {
NSArray *array = @[@"转账",@"信用卡",@"充值中心",@"蚂蚁借呗",@"电影票",@"滴滴出行",@"城市服务",@"蚂蚁森林"];
NSMutableArray *mArray = [NSMutableArray arrayWithCapacity:1];
[mArray addObjectsFromArray:array];
[mArray removeObject:x];
self.successBlock(mArray);
}];
}//当值发生改变的时候才会发生回调：（观察者模式的应用）RAC
- 结合RAC（kvo观察者模式）
- router路由（降低耦合，解决页面之间跳转，组件化之间的依赖）
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