利用CAShapeLayer在文字上画虚线(UILable举例)

来源：互联网发布：解压rar文件的软件 mac 编辑：程序博客网时间：2024/05/17 23:42

今天看到朋友有个需求，是要在lab的文字下画虚线，感觉很有意思就用CAShapeLayer研究了下，来一起看看吧。

老样子直奔主题上代码：

////  ViewController.m//  DottedLineDemo////  Created by a111 on 16/3/16.//  Copyright © 2016年 司小文. All rights reserved.//#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    self.view.backgroundColor = [UIColor blackColor];    [self makeDottedLine];    // Do any additional setup after loading the view, typically from a nib.}#pragma mark 制作虚线- (void)makeDottedLine{    //lab    NSString *str = @"司小文的博客:http://blog.csdn.net/siwen1990";    float strFont = 14.;    CGRect labRect = [str boundingRectWithSize:CGSizeMake(MAXFLOAT, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:strFont]} context:nil];    UILabel *lab = [[UILabel alloc] initWithFrame:CGRectMake((self.view.frame.size.width-labRect.size.width)/2, 100, labRect.size.width,labRect.size.height)];    lab.textColor = [UIColor whiteColor];    lab.text = str;    lab.font = [UIFont systemFontOfSize:strFont];    [self.view addSubview:lab];        //layer    CAShapeLayer *shapeLayer = [CAShapeLayer layer];    [shapeLayer setBounds:lab.bounds];    [shapeLayer setPosition:lab.center];    [shapeLayer setFillColor:[[UIColor redColor] CGColor]];        //设置虚线的颜色 - 颜色请必须设置    [shapeLayer setStrokeColor:[[UIColor whiteColor] CGColor]];        //设置虚线的高度    [shapeLayer setLineWidth:1.0f];        //设置类型    [shapeLayer setLineJoin:kCALineJoinRound];        /*        10.f=每条虚线的长度        3.f=每两条线的之间的间距     */    [shapeLayer setLineDashPattern:     [NSArray arrayWithObjects:[NSNumber numberWithInt:10.f],      [NSNumber numberWithInt:3.f],nil]];        // Setup the path    CGMutablePathRef path1 = CGPathCreateMutable();        /*        代表初始坐标的x，y        x:写-2,是为了视觉上，虚线比文字稍长一点。        y:要和下面的y一样。     */    CGPathMoveToPoint(path1, NULL,-2, lab.frame.size.height);        /*        代表坐标的x，y        lab.frame.size.width+2：我觉得他代表的意思可以理解为线的长度。        lab.frame.size.height：要与上面的y大小一样，才能使平行的线，不然会画出斜线呦~     */    CGPathAddLineToPoint(path1, NULL, lab.frame.size.width+2,lab.frame.size.height);        //赋值给shapeLayer    [shapeLayer setPath:path1];        //清除    CGPathRelease(path1);        //可以把self改成任何你想要的UIView.    [[self.view layer] addSublayer:shapeLayer];    }- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end

效果图：

注释写的很清楚但是demo还是要奉上的：

CAShapeLayer画虚线-司小文（提取码：e684）

感谢观看，学以致用更感谢。

0 0