如何实现OC下划虚线

封装一个画虚线的类

.h文件

 #import <UIKit/UIKit.h>    
@interface PHDashedLineView : UIView   
@property(nonatomic,assign)CGPoint startPoint;//虚线起点    
@property(nonatomic,assign)CGPoint endPoint;//虚线终点    
@property(nonatomic,strong)UIColor* lineColor;//虚线颜色
@property(nonatomic,assign)CGFloat solidWidth; //虚线中横线的宽度
@property(nonatomic,assign)CGFloat spaceWidth; //虚线中空白地方的宽度
@end

.m文件

#import "PHDashedLineView.h"

@implementation PHDashedLineView

- (void)drawRect:(CGRect)rect{
CGContextRef context = UIGraphicsGetCurrentContext(); //设置上下文
CGContextSetStrokeColorWithColor(context, _lineColor.CGColor);//线条颜色
CGContextSetLineWidth(context, 1.0);//线条宽度
CGContextMoveToPoint(context, _startPoint.x, _startPoint.y); //开始画线, x，y 为开始点的坐标
CGContextAddLineToPoint(context, _endPoint.x, _endPoint.y);//画直线, x，y 为线条结束点的坐标
CGFloat lengths[] = {_solidWidth,_spaceWidth};
CGContextSetLineDash(context, 0, lengths, 2);
CGContextStrokePath(context); //开始画线
}

@end

使用

PHDashedLineView *view = [[PHDashedLineView alloc] initWithFrame:CGRectMake(0, PCView_H(self) - 1, SCREEN_WIDTH, 1)];
view.backgroundColor = [UIColor clearColor];
view.lineColor = COLORRGB187;
view.solidWidth = 1;
view.spaceWidth = 5;
view.startPoint = CGPointMake(0, 0);
view.endPoint = CGPointMake(self.frame.size.width, 0);
_dashedView = view;
[self addSubview:view];

上面例子中最后结果是画了一条水平的直线，可以通过开始和结束的坐标画出不同倾斜度的直线出来，如果在这行代码<code>view.endPoint = CGPointMake(self.frame.size.width, 0);</code>后面加上<code>view.endPoint = CGPointMake(self.frame.size.width, 120);</code>就会画出一条折线出来

更多好玩的，大家可以慢慢琢磨

网上还看到一种写法，使用<code>CAShapeLayer</code>来绘制，下面附上代码：

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 132, 150)];
view.backgroundColor = [UIColor cyanColor];
[self.view addSubview:view];

CAShapeLayer *shapeLayer = [CAShapeLayer layer];
[shapeLayer setFrame:view.bounds];
[shapeLayer setPosition:CGPointMake(0, 0)];
[shapeLayer setFillColor:[[UIColor clearColor] CGColor]];
// 设置虚线的颜色
[shapeLayer setStrokeColor:[[UIColor blackColor] CGColor]];
// 设置虚线的高度
[shapeLayer setLineWidth:1.0f];
[shapeLayer setLineJoin:kCALineJoinRound];
// 3=线的宽度 1=每条线的间距
[shapeLayer setLineDashPattern:
 [NSArray arrayWithObjects:[NSNumber numberWithInt:3],
  [NSNumber numberWithInt:1],nil]];

// Setup the path
CGMutablePathRef path = CGPathCreateMutable();
//给出起始和终点path
CGFloat coordinateX = view.frame.size.width / 2;
CGFloat coordinateY = view.frame.size.height / 2 * 3;
CGPathMoveToPoint(path, NULL, coordinateX, coordinateY);
CGPathAddLineToPoint(path, NULL, coordinateX + view.frame.size.width,coordinateY);
CGPathAddLineToPoint(path, NULL, coordinateX + view.frame.size.width,coordinateY - view.frame.size.height);
[shapeLayer setPath:path];

[[view layer] addSublayer:shapeLayer];

CGPathRelease(path);

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