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浅谈MVC&变异MVC&MVP&MVVM

稍微做过几年开发的一定都听过MVC、MVP、MVVM这些架构名称吧。其实不论我们用哪一种机构模式，总会有一个地方造成臃肿，我们需要根据我们的具体业务使用更加合适的架构模式。而不能迷信哪种架构模式比较先进什么的。。。

MVC

MVC

MVC的优点和缺点都是很明显

  • 优点：View、Model都是可以重复利用的，可以独立使用
  • 缺点：Controller的代码过于臃肿。

对于MVC，iOS中最为典型的就是UITableview的时候，UITableview几乎是对MVC架构用到了极致。我们平时创建UITableview、UITableviewCell、Model，这就是最为常见的MVC架构。

今天我们对一个view进行一些实现

MVC1

APPView代码

@class APPView;
@protocol MyAppViewDelegate <NSObject>
@optional
- (void)appViewDidClick:(APPView *)appView;
@end

@interface APPView : UIView

@property (nonatomic,strong) UIImageView *iconView;
@property (nonatomic,strong) UILabel *nameLabel;

@property (weak, nonatomic) id<MyAppViewDelegate> delegate;

@end



实现

- (instancetype)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame]) {
UIImageView *iconView = [[UIImageView alloc] init];
iconView.frame = CGRectMake(0, 0, 100, 100);
[self addSubview:iconView];
_iconView = iconView;

UILabel *nameLabel = [[UILabel alloc] init];
nameLabel.frame = CGRectMake(0, 100, 100, 30);
nameLabel.textAlignment = NSTextAlignmentCenter;
[self addSubview:nameLabel];
_nameLabel = nameLabel;
}
return self;
}


- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
if ([self.delegate respondsToSelector:@selector(appViewDidClick:)]) {
[self.delegate appViewDidClick:self];
}
}

APPModel代码

@interface APPModel : NSObject

@property (nonatomic,copy) NSString *name;
@property (nonatomic,copy) NSString *image;

@end

Controller实现

- (void)viewDidLoad {
[super viewDidLoad];


//创建view
APPView *app = [[APPView alloc]initWithFrame:CGRectMake(100, 100, 100, 150)];
app.delegate = self;
[self.view addSubview:app];

//创建model
APPModel *model = [[APPModel alloc]init];
model.name = @"我是一片云";
model.image = @"cloud";

//赋值
app.nameLabel.text = model.name;
app.iconView.image = [UIImage imageNamed:model.image];

}

#pragma mark -- view点击事件 --
- (void)appViewDidClick:(APPView *)appView{
NSLog(@"点击了view");
}

为了更加明白的看出来MVC，我这里有单独的实现了一个APPModel，我们查看代码可以看到，大量的业务逻辑需要再Controller里面处理。我们需要处理View的创建，赋值，实现点击事件，这些功能就造成了Controller的臃肿。但是好处也是有的，因为View和Model互相不知道对方是谁，我们可以重复利用他们。

变异MVC

MVC2

变异MVC其实就是View也持有Model，将View内部的细节封装起来了

  • 优点：对Controller进行瘦身，将View内部的细节封装起来了，外界不知道View内部的具体实现
  • 缺点：View依赖于Model

APPView代码

#import <UIKit/UIKit.h>
#import "APPModel.h"
NS_ASSUME_NONNULL_BEGIN

@class APPView;
@protocol MyAppViewDelegate <NSObject>
@optional
- (void)appViewDidClick:(APPView *)appView;
@end

@interface APPView : UIView

@property (nonatomic,strong) APPModel *model;
@property (weak, nonatomic) id<MyAppViewDelegate> delegate;

@end


//实现
#import "APPView.h"
@interface APPView ()
@property (nonatomic,strong) UIImageView *iconView;
@property (nonatomic,strong) UILabel *nameLabel;
@end
@implementation APPView

- (instancetype)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame]) {
UIImageView *iconView = [[UIImageView alloc] init];
iconView.frame = CGRectMake(0, 0, 100, 100);
[self addSubview:iconView];
_iconView = iconView;

UILabel *nameLabel = [[UILabel alloc] init];
nameLabel.frame = CGRectMake(0, 100, 100, 30);
nameLabel.textAlignment = NSTextAlignmentCenter;
[self addSubview:nameLabel];
_nameLabel = nameLabel;
}
return self;
}


- (void)setModel:(APPModel *)model{
_model = model;
_iconView.image = [UIImage imageNamed:model.image];
_nameLabel.text = model.name;
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
if ([self.delegate respondsToSelector:@selector(appViewDidClick:)]) {
[self.delegate appViewDidClick:self];
}
}

@end

代码变化是view持有了Model，然后把view的实现方法了匿名函数里面了。model的结构还是不变

Controller实现

- (void)viewDidLoad {
[super viewDidLoad];


//创建view
APPView *app = [[APPView alloc]initWithFrame:CGRectMake(100, 100, 100, 150)];
app.delegate = self;
[self.view addSubview:app];

//创建model
APPModel *model = [[APPModel alloc]init];
model.name = @"我是一片云";
model.image = @"cloud";

//赋值
app.model = model;
}

#pragma mark -- view点击事件 --
- (void)appViewDidClick:(APPView *)appView{
NSLog(@"点击了view");
}

在controller里面我们不在controller里面对view进行实现，需要把Model的值传给View

MVP

MVP

MVP是controller不在持有 View和Model，而是有一个Presenter类持有。

Presenter实现

@interface APPPresenter ()<MyAppViewDelegate>
@property (weak, nonatomic) UIViewController *controller;
@end

@implementation APPPresenter
- (instancetype)initWithController:(UIViewController *)controller{
if (self = [super init]) {
_controller = controller;
//创建view
APPView *app = [[APPView alloc]initWithFrame:CGRectMake(100, 100, 100, 150)];
app.delegate = self;
[controller.view addSubview:app];

//创建model
APPModel *model = [[APPModel alloc]init];
model.name = @"我是一片云";
model.image = @"cloud";

//赋值
app.model = model;
}

return self;
}

#pragma mark -- view点击事件 --
- (void)appViewDidClick:(APPView *)appView{
NSLog(@"点击了view");
}

Controller实现

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.

self.presenter = [[APPPresenter alloc]initWithController:self];

}

【注意】：要把APPPresenter设置为全部变量，如果设置为局部变量的话，会在出函数以后presenter对象就会被销毁。

其实MVP就是我们在专门做一个APPPresenter类，把controller里面方法给方法APPPresenter类里面

MVVM

使用MVVM最好的框架是ReactiveCocoa，但是这个框架是重量级的框架，学习成本还是比较大的，如果项目中主要使用的架构就是MVVM，那么用这个框架是非常好的，如果只是局部使用的话我们可以使用KVOController来简单的替代一下

MVVM

MVVM我感觉好像跟MVP有点类似，但是比MVP多了一个功能，就是在view改变时，model也能及时改变，在model改变时view也能及时改变

APPView代码

#import "APPView.h"
#import "NSObject+FBKVOController.h"
@interface APPView ()
@property (nonatomic,strong) UIImageView *iconView;
@property (nonatomic,strong) UILabel *nameLabel;
@end
@implementation APPView

- (instancetype)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame]) {
UIImageView *iconView = [[UIImageView alloc] init];
iconView.frame = CGRectMake(0, 0, 100, 100);
[self addSubview:iconView];
_iconView = iconView;

UILabel *nameLabel = [[UILabel alloc] init];
nameLabel.frame = CGRectMake(0, 100, 100, 30);
nameLabel.textAlignment = NSTextAlignmentCenter;
[self addSubview:nameLabel];
_nameLabel = nameLabel;
}
return self;
}


- (void)setModel:(APPModel *)model{
_model = model;
_iconView.image = [UIImage imageNamed:model.image];
_nameLabel.text = model.name;


__weak typeof(self) waekSelf = self;
[self.KVOController observe:model keyPath:@"name" options:NSKeyValueObservingOptionNew block:^(id  _Nullable observer, id  _Nonnull object, NSDictionary<NSKeyValueChangeKey,id> * _Nonnull change) {
waekSelf.nameLabel.text = change[NSKeyValueChangeNewKey];
}];

[self.KVOController observe:model keyPath:@"image" options:NSKeyValueObservingOptionNew block:^(id  _Nullable observer, id  _Nonnull object, NSDictionary<NSKeyValueChangeKey,id> * _Nonnull change) {
waekSelf.iconView.image = [UIImage imageNamed:change[NSKeyValueChangeNewKey]];
}];

}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
if ([self.delegate respondsToSelector:@selector(appViewDidClick:)]) {
[self.delegate appViewDidClick:self];
}
}

在实现model的set方法时，要监听model值的变化。

viewModel的实现

- (instancetype)initWithController:(UIViewController *)controller{
if (self = [super init]) {

_controller = controller;
//创建view
APPView *app = [[APPView alloc]initWithFrame:CGRectMake(100, 100, 100, 150)];
app.delegate = self;
[controller.view addSubview:app];

//创建model
APPModel *model = [[APPModel alloc]init];
model.name = @"我是一片云";
model.image = @"cloud";

//赋值
app.model = model;
}

return self;
}

#pragma mark -- view点击事件 --
- (void)appViewDidClick:(APPView *)appView{
NSLog(@"点击了view");

appView.model.name = [NSString stringWithFormat:@"%d",arc4random()%100];

NSLog(@"%@",appView.model.name);
}

viewModel实现跟Presenter实现是类似的。