How does iOS draw dashed lines?

Overriding the DrawRect method

Preparing: Inheriting UIView subclasses

1.. h file

//

DashesLineView.h

Inface

//

Created by Huangzengsong on 15/5/11.

Copyright (c) 2015 Huangzs. All rights reserved.

//

#import <UIKit/UIKit.h>

@interface Dasheslineview:uiview

@property (nonatomic) cgpoint startpoint;//dashed start

@property (nonatomic) cgpoint endpoint;//dashed End

@property (Nonatomic,strong) uicolor* linecolor;//dashed color

@end

2.. m file

//

dasheslineview.m

Inface

//

Created by Huangzengsong on 15/5/11.

Copyright (c) 2015 Huangzs. All rights reserved.

//

#import "DashesLineView.h"

@implementation Dasheslineview

-(ID) initWithFrame: (CGRect) frame

{

self= [Super Initwithframe:frame];

if (self) {

Initialization code

}

return self;

}

Only override Drawrect:if perform custom drawing.

An empty implementation adversely affects performance during animation.

-(void) DrawRect: (cgrect) rect

{

Cgcontextref context =uigraphicsgetcurrentcontext ();

Cgcontextbeginpath (context);

Cgcontextsetlinewidth (context,1);//Line width

Cgcontextsetstrokecolorwithcolor (Context,self.linecolor.cgcolor);

CGFloat lengths[] = {1,2};//First draw 4 points and then draw 2 points

Cgcontextsetlinedash (context,0, lengths,2);//Note the value of 2 (count) equals the length of the lengths array

Cgcontextmovetopoint (CONTEXT,SELF.STARTPOINT.X,SELF.STARTPOINT.Y);

Cgcontextaddlinetopoint (CONTEXT,SELF.ENDPOINT.X,SELF.ENDPOINT.Y);

Cgcontextstrokepath (context);

Cgcontextclosepath (context);

}

/*

Only override Drawrect:if perform custom drawing.

An empty implementation adversely affects performance during animation.

-(void) DrawRect: (cgrect) Rect {

Drawing Code

}

*/

@end

3. When to adjust

Self. Dashlineview.startpoint=cgpointmake (0, 1);

Self. Dashlineview.endpoint=cgpointmake (

[[UIScreen Mainscreen] Bounds].size.width

-40, 1);

Self. Dashlineview.linecolor=

[Uicolor colorwithred:28.0/255.0 green:160.0/255.0 blue:229.0/255.0 alpha:1]

;

How does iOS draw dashed lines?