前言：说到设计模式，许多人认为是很高深的东西，其实许多都是由简单演变而来，或许MVC模式并不难理解因为熟悉，其他模式其实也是同样如此。MVC ->MVP ->MVVM 每次演变都是为了低耦合，易维护的目的，但也不是一成不变，多种混合也是可以同时存在， 所以我们需要抓住每个理念的核心概念，选择合适的方式应用到工程中理解会更深！
参考文献：https://blog.nodejitsu.com/scaling-isomorphic-javascript-code/
一、MVC
MVC
由屏幕获取响应指令， View 传送指令到 Controller，Controller 完成业务逻辑后，要求Model 改变状态Model 将新的数据发送到 View，用户得到反馈
MVCViewController.m
#import "MVCViewController.h"
#import "MVCView.h"
#import "MVCModel.h"
@interface MVCViewController ()<MVCDelegate>
@end
@implementation MVCViewController
- (void)viewDidLoad {
[super viewDidLoad];
MVCView *view = [[MVCView alloc]initWithFrame:[UIScreen mainScreen].bounds];
view.delegate = self;
MVCModel *model = [MVCModel new];
model.name = @"name1";
[view setViewWithModel:model];
}
#pragma mark - delegate
//代理来返回view对viewController的操控
-(void)clickChange{
NSLog(@"chang from View!");
}
二、 MVP
MVP 模式将 Controller 改换为 Presenter，同时断开View和Model之间联系，通过Presenter做桥梁来沟通。
** MVP**
- 各部分之间的通信，都是双向的。
- View 与 Model 不发生联系，都通过 Presenter 传递。
- View 非常薄，不部署任何业务逻辑，称为"被动视图"（Passive View），即没有任何主动性，而 Presenter非常厚，所有逻辑都部署在那里。
- Presenter 可以另一种理解为View和Model的管家
MVPViewController.m
#import "MVPViewController.h"
#import "MVPPresenter.h"
#import "MVPCell.h"
#import "MVPModel.h"
@implementation MVPViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
self.view.backgroundColor = [UIColor whiteColor];
MVPPresenter *present = [MVPPresenter new];
MVPCell *view = [MVPCell new];
MVPModel *model = [MVPModel new];
//获取数据
model.name = @"name1";
//视图布局
[self.view addSubview:view];
//交给presenter处理 ，避免 view和 model 之间的交互
[present setPreModel:model];
[present setPreView:view];
}
MVPPresenter .h /.m
#import <Foundation/Foundation.h>
#import "MVPModel.h"
#import "MVPCell.h"
@interface MVPPresenter : NSObject
@property(nonatomic,strong)MVPCell *MVPView;
@property(nonatomic,strong)MVPModel *model;
-(void)setPreView:(MVPCell *)view;
-(void)setPreModel:(MVPModel *)model;
-(void)clickChangName;
#import "MVPPresenter.h"
@implementation MVPPresenter
- (instancetype)init
{
self = [super init];
if (self) {
}
return self;
}
-(void)setPreModel:(MVPModel *)model{
self.model = model;
}
-(void)setPreView:(MVPCell *)view{
self.MVPView = view;
[self.MVPView setlabel:_model.name];
}
-(void)clickChangName{
NSLog(@"name change %d",arc4random()%10);
}
三、MVVM
MVVM 模式将 Presenter 改名为 ViewModel，基本上与 MVP 模式完全一致。
唯一的区别是，它采用双向绑定（data-binding）：View <->ViewModel , ViewModel作为Model中值得的映射，是数据发生改变时，通知View中发生改变 ，以后不需要考虑View和Model 之间的交互更新，只需着手界面布局逻辑即可
MVVMViewController.m
#import "MVVMViewController.h"
#import "MVVMView.h"
#import "MVVMModel.h"
#import "MVVMViewModel.h"
@interface MVVMViewController ()
@end
@implementation MVVMViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
MVVMView *MView = [MVVMView new];
MVVMModel *model = [MVVMModel new];
model.name = @"name1";
MVVMViewModel *viewModel = [MVVMViewModel new];
[self.view addSubview:MView];
//* viewModel 作为枢纽 沟通view和model之间关系
[viewModel setWithModel:model];
[MView setWithViewMoel:viewModel];
}
关键点：
- 将viewModel 中
nameStr与Model 中name相对应； - View中
label的text值将与nameStr进行绑定(KVO键值观察) - 这样model的值发生改变时 ，View会自动发生改变
- View 和Model通过ViewModel实现动态关联
**MVVMModel **
#import <Foundation/Foundation.h>
@interface MVVMModel : NSObject
@property(nonatomic,copy)NSString *name;
@end
MVVMViewModel.h
#import "MVVMModel.h"
@interface MVVMViewModel : NSObject
//对应Model中name
@property(nonatomic,copy)NSString *nameStr;
@property(nonatomic,strong)MVVMModel *model;
-(void)setWithModel:(MVVMModel *)model;
-(void)clickChangeName;
MVVMView.m 利用KVO监测值变化
#import "MVVMView.h"
#import "NSObject+FBKVOController.h"
@interface MVVMView ()
@property(nonatomic,strong)MVVMViewModel *vm;
@property(nonatomic,strong)UILabel *label;
@property(nonatomic,strong)UIButton *button;
@end
@implementation MVVMView
- (instancetype)init
{
self = [super init];
if (self) {
self.backgroundColor = [UIColor whiteColor];
self.frame = [UIScreen mainScreen].bounds;
self.label = [[UILabel alloc]initWithFrame:CGRectMake(150,100 , 100, 30)];
self.label.backgroundColor = [UIColor orangeColor];
[self addSubview:_label];
self.button = [UIButton new];
_button.backgroundColor = [UIColor redColor];
[_button setTitle:@"点击" forState:UIControlStateNormal];
[_button addTarget:self action:@selector(mvvmClickChangModel) forControlEvents:UIControlEventTouchUpInside];
_button.frame = CGRectMake(150, 200, 50, 50);
[self addSubview:_button];
}
return self;
}
-(void)setWithViewMoel:(MVVMViewModel *)vm{
self.vm = vm;
//KVO
[self.vm addObserver:self forKeyPath:@"nameStr" options:NSKeyValueObservingOptionOld|NSKeyValueObservingOptionNew context:nil];
self.label.text = vm.nameStr;
// //* FBKVO 第三方库
// [self.KVOController observe:self.vm keyPath:@"nameStr" options:NSKeyValueObservingOptionInitial|NSKeyValueObservingOptionNew block:^(id _Nullable observer, id _Nonnull object, NSDictionary<NSString *,id> * _Nonnull change) {
// self.label.text = change[NSKeyValueChangeNewKey];
// }];
}
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change: (NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context{
if ([keyPath isEqualToString:@"nameStr"]&&[change objectForKey:NSKeyValueChangeNewKey]) {
NSNumber *new = [change objectForKey:NSKeyValueChangeNewKey];
self.label.text = [NSString stringWithFormat:@"%@",new];
}
}
-(void)mvvmClickChangModel{
[self.vm clickChangeName];
}
-(void)dealloc{
[self.vm removeObserver:self forKeyPath:@"nameStr"];
}
