使用手势UIPanGestureRecognizer作为手指在屏幕上滑动获取坐标方式，摒弃touches:begin; touches:moved。
// 初始化设置
- (void)setUp
{
// 添加pan手势
_pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
_pan.delegate=self;
_pan.maximumNumberOfTouches = 1;
[self addGestureRecognizer:_pan];
_lineWidth = 1;
_pathColor= [UIColorblackColor];
}
UIPanGestureRecognizer方法
// 当手指拖动的时候调用
- (void)pan:(UIPanGestureRecognizer *)pan
{
// 获取当前手指触摸点
CGPointcurP = [panlocationInView:self];
CGPointmidPoint =midpoint(_prePoint, curP);
// 获取开始点
if (pan.state == UIGestureRecognizerStateBegan) {
// 创建贝瑟尔路径
_path= [[WDDrawPathalloc]init];
// 设置线宽
_path.lineWidth = _lineWidth;
// 给路径设置颜色
_path.pathColor = _pathColor;
// 设置路径的起点
[_pathmoveToPoint:curP];
_startPoint= curP;
// 保存描述好的路径
[self.pathsaddObject:_path];
}
if (pan.state==UIGestureRecognizerStateEnded) {
_endPoint= curP;
}
if (pan.state==UIGestureRecognizerStateChanged) {
if(self.viewType==kQuXian) {
[_path addQuadCurveToPoint:midPoint controlPoint:_prePoint];
}elseif(self.viewType==kZhiXian) {
[_pathremoveAllPoints];
[_pathmoveToPoint:_startPoint];
[_pathaddLineToPoint:_endPoint];
}elseif(self.viewType==kJuXing) {
[_pathremoveAllPoints];
[_pathmoveToPoint:_startPoint];
CGPointleftBottomPoint =CGPointMake(_startPoint.x, curP.y);
CGPointrightTopPoint =CGPointMake(curP.x,_startPoint.y);
[_pathaddLineToPoint:leftBottomPoint];
[_pathaddLineToPoint:curP];
[_pathaddLineToPoint:rightTopPoint];
[_pathaddLineToPoint:_startPoint];
}
_endPoint= curP;
}
// 手指一直在拖动
// 添加线到当前触摸点
_prePoint= curP;
// 重绘
[self setNeedsDisplay];
}