重寫drawRect方法

准備：繼承UIView的子類

.h文件

#import<UIKit/UIKit.h>

@interfaceDashesLineView :UIView

@property(nonatomic)CGPointstartPoint;//虛線起點

@property(nonatomic)CGPointendPoint;//虛線終點

@property(nonatomic,strong)UIColor* lineColor;//虛線顏色

@end
.m文件

#import"DashesLineView.h"

@implementationDashesLineView

- (id)initWithFrame:(CGRect)frame

{

self= [superinitWithFrame:frame];

if(self) {

// Initialization code

}

returnself;

}

// Only override drawRect: if you perform custom drawing.

// An empty implementation adversely affects performance during animation.

- (void)drawRect:(CGRect)rect

{

CGContextRefcontext =UIGraphicsGetCurrentContext();

CGContextBeginPath(context);

CGContextSetLineWidth(context,0.5);//線寬度

CGContextSetStrokeColorWithColor(context,self.lineColor.CGColor);

CGFloatlengths[] = {4,2};//先畫4個點再畫2個點

CGContextSetLineDash(context,0, lengths,2);//注意2(count)的值等於lengths數組的長度

CGContextMoveToPoint(context,self.startPoint.x,self.startPoint.y);

CGContextAddLineToPoint(context,self.endPoint.x,self.endPoint.y);

CGContextStrokePath(context);

CGContextClosePath(context);

}

@end