UITouch触摸事件

• 主要为三个方法

1.-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{2.3.    UITouch *touch = [touches anyObject];4.    CGPoint point = [touch locationInView:self];5.    start = point;6.    end = point;7.8.}9.10.-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{11.12.    UITouch *touch = [touches anyObject];13.    CGPoint point = [touch locationInView:self];14.    end = point;15.16.    [self setNeedsDisplay];17.}18.19.-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{20.21.    UITouch *touch = [touches anyObject];22.    CGPoint point = [touch locationInView:self];23.    end = point;24.25.    [self setNeedsDisplay];26.27.28.}29.

• 示例

1.#import "myView.h"2.3.@interface myView ()4.{5.    CGPoint start;6.    CGPoint end;7.}8.@end9.10.11.@implementation myView12.13.-(instancetype)initWithFrame:(CGRect)frame{14.    if (self = [super initWithFrame:frame]) {15.        self.backgroundColor = [UIColor whiteColor];16.    }17.    return self;18.}19.20.21.22.-(void)drawRect:(CGRect)rect{23.24.    if (start.x != end.x && start.y != end.y) {25.26.        CGFloat w = fabs(end.x - start.x);27.        CGFloat h = fabs(end.y - start.y);28.29.        CGFloat x = end.x < start.x ? end.x : start.x;30.        CGFloat y = end.y < start.y ? end.y : start.y;31.32.        //画圆33.        UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:34.                              CGRectMake(x, y, w, h)];35.36.        //画方37.//        UIBezierPath *path = [UIBezierPath bezierPathWithRect:CGRectMake(x, y, w, h)];38.39.        [[UIColor redColor] setStroke];40.        [path stroke];41.    }42.43.}44.45.-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{46.47.    UITouch *touch = [touches anyObject];48.    CGPoint point = [touch locationInView:self];49.    start = point;50.    end = point;51.52.}53.54.-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{55.56.    UITouch *touch = [touches anyObject];57.    CGPoint point = [touch locationInView:self];58.    end = point;59.60.    [self setNeedsDisplay];61.}62.63.-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{64.65.    UITouch *touch = [touches anyObject];66.    CGPoint point = [touch locationInView:self];67.    end = point;68.69.    [self setNeedsDisplay];70.71.72.}73.74.75.76.77.@end78.