触摸的target-action delegate设计思想的运用

目标:当点击一个类的视图对象的时候,做一些响应,点击该类不同的视图对象做出的响应不同

而触发时机是点击该视图时,所以在- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event这个方法让代理去执行任务

1.定义协议

@classTouchView;//当定义协议的时候TouchView还没出现

@protocol TouchViewDelegate <NSObject>

    //协议中存在四个方法,对应触摸的四个时机,当视图对象接收到不同的触摸事件之后,通过协议中的方法通知代理对象

@optional

- (void)touchViewTouchesBegan:(TouchView *)touchView;

- (void)touchViewTouchesMoved:(TouchView *)touchView;

- (void)touchViewTouchesEnded:(TouchView *)touchView;

- (void)touchViewTouchesCancelled:(TouchView *)touchView;

@end

@interface TouchView :UIView

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

//代理是通过属性的形似出现的

@end

2.遵守协议

@interfaceDelegateViewController ()<TouchViewDelegate>

@end

3.设置代理

- (void)viewDidLoad

{

    [superviewDidLoad];

    // Do any additional setup after loading the view.

    self.view.backgroundColor = [UIColorcyanColor];

   TouchView *redView = [[TouchViewalloc]initWithFrame:CGRectMake(20,50, 280, 40)];

    redView.backgroundColor = [UIColorredColor];

    redView.tag =100;

        //为视图指定代理,来处理视图的触摸事件

    redView.delegate =self;

    [self.viewaddSubview:redView];

    [redViewrelease];

    

    

    

   TouchView *blueView = [[TouchViewalloc]initWithFrame:CGRectMake(20,120, 280, 40)];

    blueView.backgroundColor = [UIColorblueColor];

    blueView.tag =101;

    blueView.delegate =self;

    [self.viewaddSubview:blueView];

    [blueViewrelease];

    

        //grayView

   TouchView *grayView = [[TouchViewalloc]initWithFrame:CGRectMake(20,450, 280, 100)];

    grayView.backgroundColor = [UIColorgrayColor];

    grayView.tag =102;

    grayView.delegate =self;

    [self.viewaddSubview:grayView];

    [grayViewrelease];

}

4.让代理做事情的一个时机

//代理设计模式思想:对于当前视图对象,只负责接收触摸事件,当触摸事件发生之后,通知代理做相应处理,代理如何处理视图不关心

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

{

        //原理:

        //如果代理实现了协议的方法,就让代理调用方法,如果没有实现就不要调用

        //判断代理是否实现了对应的方法(判断一个对象是否实现某个特定的方法)

    if ([self.delegate respondsToSelector:@selector(touchViewTouchesBegan:)]) {

            //触摸开始时通知代理做相应的操作

        [self.delegate touchViewTouchesBegan:self];

    }

    

}

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

{

        //respondsToSelector:@selector 返回BOOL类型

    if ([self.delegate respondsToSelector:@selector(touchViewTouchesMoved:)]) {

            //触摸移动时通知代理做相应的操作

        [self.delegate touchViewTouchesMoved:self];

    }

    

}

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

{

    if ([self.delegate respondsToSelector:@selector(touchViewTouchesEnded:)]) {

            //触摸结束时通知代理做相应的操作

        [self.delegate touchViewTouchesEnded:self];

    }

    

}

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

{

    if ([self.delegate respondsToSelector:@selector(touchViewTouchesCancelled:)]) {

            //触摸取消时通知代理做相应的操作

        [self.delegate touchViewTouchesCancelled:self];

    }

    

}

5.代理做的事情

- (void)touchViewTouchesBegan:(TouchView *)touchView

{

    //匹配的用switch

    switch (touchView.tag) {

       case 100:

            touchView.backgroundColor = [UIColorrandomColor];

           break;

       case 101:

            touchView.superview.backgroundColor = [UIColor randomColor];

           break;

       case 102:

            touchView.center =CGPointMake(arc4random() %200 + 100, arc4random() %400 + 100);

           break;

            

       default:

           break;

    }

}