事件处理

- (BOOL)canBecomeFirstResponder;    // default is NO
- (BOOL)becomeFirstResponder;

- (BOOL)canResignFirstResponder;    // default is YES
- (BOOL)resignFirstResponder;

- (BOOL)isFirstResponder;

// 手指触摸
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
// 手指移动
- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
// 手指移开   —> 这三个是一个完整的响应事件
- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;
// 手指取消  —> 非正常手指移开（突然接电话什么时候会调用）
- (void)touchesCancelled:(nullable NSSet<UITouch *> *)touches withEvent:(nullable UIEvent *)event;

// 触摸时间
@property(nonatomic,readonly) NSTimeInterval      timestamp;
@property(nonatomic,readonly) UITouchPhase        phase;
@property(nonatomic,readonly) NSUInteger          tapCount;   // touch down within a certain point within a certain amount of time
@property(nonatomic,readonly) UITouchType        type NS_AVAILABLE_IOS(9_0);

// majorRadius and majorRadiusTolerance are in points
// The majorRadius will be accurate +/- the majorRadiusTolerance
@property(nonatomic,readonly) CGFloat majorRadius NS_AVAILABLE_IOS(8_0);
@property(nonatomic,readonly) CGFloat majorRadiusTolerance NS_AVAILABLE_IOS(8_0);

@property(nullable,nonatomic,readonly,strong) UIWindow                        *window;
@property(nullable,nonatomic,readonly,strong) UIView                          *view;
@property(nullable,nonatomic,readonly,copy)   NSArray <UIGestureRecognizer *> *gestureRecognizers NS_AVAILABLE_IOS(3_2);

- (CGPoint)locationInView:(nullable UIView *)view;
- (CGPoint)previousLocationInView:(nullable UIView *)view;

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
   
   
    // 1.单击，子view变成中心
    UITouch *touch = touches.anyObject;
   
    // 获得现在的点
    CGPoint nowPoint = [touch locationInView:self.superview];

    self.center = nowPoint;
   

}

- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
   
    // 3.拖拽时候跟着鼠标走
    UITouch *touch = touches.anyObject;
    // 获得当前的点
    CGPoint previousPoint = [touch previousLocationInView:self.superview];
    // 获得现在的点
    CGPoint nowPoint = [touch locationInView:self.superview];
    NSLog(@"%@",NSStringFromCGPoint(nowPoint));
    NSLog(@"%@",NSStringFromCGPoint(previousPoint));
    // 获取x，y偏移量
    CGFloat x = nowPoint.x - previousPoint.x;
    CGFloat y = nowPoint.y - previousPoint.y;
    self.transform = CGAffineTransformTranslate(self.transform,x , y);
  
}
主view
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
   
    // 点击外面view时候，橘色view中心变变成点击点
    UITouch *touch = touches.anyObject;
    self.orangeView.center = [touch locationInView:self];
}
 

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
   
    NSLog(@"%@",self.imageArray); // 这个是有的，好的.
   
   
    for (UITouch *t in touches) {
       
        CGPoint nowPoint = [t locationInView:self.superview];
       
        UIImageView *imgView = [[UIImageView alloc] initWithImage:[self ramdomImage]];
       
        imgView.center = nowPoint;
       
        [self addSubview:imgView];
       
        [UIView animateWithDuration:2.0 animations:^{
           
            imgView.alpha = 0;
           
        } completion:^(BOOL finished) {
            [imgView removeFromSuperview];
        }];
       
    }

}

- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
   
    for (UITouch *t in touches) {
       
        CGPoint nowPoint = [t locationInView:self.superview];
       
        UIImageView *imgView = [[UIImageView alloc] initWithImage:[self ramdomImage]];
       
        imgView.center = nowPoint;
       
        [self addSubview:imgView];
       
        [UIView animateWithDuration:2.0 animations:^{
           
            imgView.alpha = 0;
           
        } completion:^(BOOL finished) {
            [imgView removeFromSuperview];
        }];
       
    }
   
   
}


- (UIImage *)ramdomImage {
   
   
    UIImage *image = self.imageArray[arc4random() % self.imageArray.count];
   
    return image;
}


// 懒加载
- (NSArray *)imageArray {
   
    if (_imageArray == nil) {
       
        _imageArray = @[[UIImage imageNamed:@"spark_1"],[UIImage imageNamed:@"spark_2"],[UIImage imageNamed:@"spark_3"],[UIImage imageNamed:@"spark_4"],[UIImage imageNamed:@"spark_5"],[UIImage imageNamed:@"spark_6"],];
    }
    return  _imageArray;
   
}