Github地址 https://github.com/zhangxiaomeng1/XMLineChartView
简书 https://www.jianshu.com/u/949e63975031
采用继承的方法，写了个基类，，重写- (void)drawRect:(CGRect)rect 方法，setNeedsDisplay 调用drawRect方法；
- (void)drawline:(CGContextRef)context
startPoint:(CGPoint)startPoint
stopPoint:(CGPoint)stopPoint
color:(UIColor *)color
lineWidth:(CGFloat)lineWitdth;
- (void)drawLabelPrice:(CGContextRef)context;
//高亮状态滑动
- (void)drawHighlighted:(CGContextRef)context
point:(CGPoint)point
idex:(NSInteger)idex
value:(id)value
color:(UIColor *)color
lineWidth:(CGFloat)lineWidth;
- (void)drawLabel:(CGContextRef)context
attributesText:(NSAttributedString *)attributesText
rect:(CGRect)rect;
//画柱状图
- (void)drawRect:(CGContextRef)context
rect:(CGRect)rect
color:(UIColor*)color;
- (void)drawGridBackground:(CGContextRef)context
rect:(CGRect)rect;