两种设计模式（解藕）

来源：互联网发布：辩证看待人工智能编辑：程序博客网时间：2024/05/17 17:43

1. target/action 设计模式

这种设计模式是为了降低程序之间的耦合程度

比如：我创建了3个轻拍View 当我轻拍不同的视图的时候（一个视图改变颜色，一个视图改变位置，一个视图改变大小）此时想到的第一种做法就是在tapView 中通过 tag进行if判断如果tag=100 执行改变颜色的方法如果tag=101 就执行其他方法等等使用这一种方法当我要再添加视图的时候发现我要在控制器中创建视图，为它添加tag，然后在转回到 tapView中添加判断与方法。这样的形式就回是程序的耦合度很低

下面使用 target/action的方法来降低耦合度

TapView.h中

#import <UIKit/UIKit.h>

@interface TapView :UIView

{

id _target;//执行 action的对象

SEL _action;//target要执行的行为

}

//为 target和 action赋值

- (void)setTarget:(id)target action:(SEL)action;

@end

TapView.m中

#import "TapView.h"

@implementation TapView

- (void)dealloc

{

[superdealloc];

}

- (id)initWithFrame:(CGRect)frame

{

self = [superinitWithFrame:frame];

if (self) {

// Initialization code

}

return self;

}

//当触摸事件触发时让target 执行 action 方法

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event

{

//点击事件结束时随机改变背景颜色

[selfchangeColor];

[_target performSelector:_actionwithObject:nil ];

//这个方法中 withObject:表示 _action需要传递的参数一般为当前对象即 self

//当_ action这个方法不需要参数而 withObject:设置为 self时这个 self并没有传递给 action

}

//为 target和 action赋值

//不带星号的一般情况下只需要直接赋值不需要 retain或者 copy

- (void)setTarget:(id)target action:(SEL)action

{

_target=target;

_action=action;

}

//随机改变当前视图的颜色

//考虑这个功能用的很多的时候可以创建一个 UIColor的分类实现获取随机颜色的UIColor对象

//这样就不用在使用此功能时都要写这么多代码

- (void)changeColor

{

//随机获取 RGB色值

CGFloat redValue=arc4random()%256/255.0;

CGFloat greenValue=arc4random()%256/255.0;

CGFloat blueValue=arc4random()%256/255.0;

//设置当前视图的背景颜色

self.backgroundColor =[UIColorcolorWithRed:redValuegreen:greenValueblue:blueValuealpha:1];

}

// Only override drawRect: if you perform custom drawing.

// An empty implementation adversely affects performance during animation.

- (void)drawRect:(CGRect)rect

{

// Drawing code

}

@end

RootViewController.m中

#import "RootViewController.h"

#import "TapView.h"

@interface RootViewController ()

@end

@implementation RootViewController

- (void)dealloc

{

[superdealloc];

}

- (void)aa

{

NSLog(@"Hello World!");

}

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil

{

self = [superinitWithNibName:nibNameOrNilbundle:nibBundleOrNil];

if (self) {

// Custom initialization

}

return self;

}

- (void)viewDidLoad

{

[superviewDidLoad];

//创建tapView类的对象作为控制器的子视图

TapView *tapView=[[TapViewalloc]initWithFrame:CGRectMake(100, 100, 100, 100)];

tapView.backgroundColor =[UIColorpurpleColor];

[tapViewsetTarget:selfaction:@selector(aa)];//这里就相当于给TapView的对象赋了一个 target 和 action的初值

[self.viewaddSubview:tapView];

[tapViewrelease];

}

- (void)didReceiveMemoryWarning

{

[superdidReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender

{

// Get the new view controller using [segue destinationViewController].

// Pass the selected object to the new view controller.

}

@end

2. 代理 delegate 设计模式

使用 delegate模式与 targt/action设计模式的区别在于 delegate 模式将代理要实现的方法固定了. 而 target/action 完全将要进行的操作交给 target来定义

任何一个代理方法都至少有一个参数(即对象本身)

两种模式的区别

1.delegate是一堆事件而 target/action 是需要几个事件,就写几个

2.调用方式不同

3.原理相同

TapView.h

#import <UIKit/UIKit.h>

@class TapView;

//使用 delegate 模式与 targt/action 设计模式的区别在于 delegate模式将代理要实现的方法固定了. 而 target/action 完全将要进行的操作交给 target来定义

//任何一个代理方法都至少有一个参数(即对象本身)

//两种模式的区别

//1.delegate 是一堆事件而 target/action 是需要几个事件,就写几个

//2.调用方式不同

//3.原理相同

//设置代理协议

@protocol TapViewDelegate <NSObject>

//tapView开始点击

- (void)tapViewBeganTouch:(TapView *)tapView;

//tapView 结束点击

- (void)tapVIewEndedTouch:(TapView *)tapView;

@optional

//tapView 正在移动

- (void)tapViewMoved:(TapView *)tapView;

@end

@interface TapView :UIView

//设置代理对象

@property (nonatomic,assign)id<TapViewDelegate> delegate;

//@property (nonatomic,assign) SEL action;

@end

TapView.m

#import "TapView.h"

@implementation TapView

- (void)dealloc

{

[superdealloc];

}

- (id)initWithFrame:(CGRect)frame

{

self = [superinitWithFrame:frame];

if (self) {

// Initialization code

}

return self;

}

//在触发事件中让代理去执行代理的实现方法

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

[_delegate tapViewBeganTouch:self];

}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event

{

[_delegate tapViewMoved:self];

}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event

{

[_delegate tapVIewEndedTouch:self];

// [_delegate performSelector:_action withObject:self];

}

// Only override drawRect: if you perform custom drawing.

// An empty implementation adversely affects performance during animation.

- (void)drawRect:(CGRect)rect

{

// Drawing code

}

@end

RootViewController.h文件（这里作为代理）

#import <UIKit/UIKit.h>

#import "TapView.h"

//代理要实现代理协议

@interface RootViewController :UIViewController<TapViewDelegate>

@end

#import "RootViewController.h"

#import "TapView.h"

@interface RootViewController ()

@end

RootViewController.m

@implementation RootViewController

- (void)dealloc

{

[superdealloc];

}

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil

{

self = [superinitWithNibName:nibNameOrNilbundle:nibBundleOrNil];

if (self) {

// Custom initialization

}

return self;

}

- (void)viewDidLoad

{

[superviewDidLoad];

TapView *tapView=[[TapViewalloc]initWithFrame:CGRectMake(100, 100, 100, 100)];

tapView.backgroundColor=[UIColorblueColor];

tapView.delegate=self; //初始化时为 tapView的对象指定代理对象

// tapView.action=@selector(aa:);

[self.viewaddSubview:tapView];

[tapViewrelease];

}

- (void)didReceiveMemoryWarning

{

[superdidReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

- (void)aa:(TapView *)tapView

{

tapView.backgroundColor=[UIColorredColor];

NSLog(@"我是 delegate设计模式");

}

//实现代理方法

- (void)tapViewBeganTouch:(TapView *)tapView

{

NSLog(@"开始");

}

- (void)tapViewMoved:(TapView *)tapView

{

NSLog(@"移动 ");

}

- (void)tapVIewEndedTouch:(TapView *)tapView

{

NSLog(@"结束");

}

#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender

{

// Get the new view controller using [segue destinationViewController].

// Pass the selected object to the new view controller.

}

@end

0 0