画直线

方法一(推荐)：使用CALayer

CALayer *middleBorder = [CALayer layer];
middleBorder.frame = CGRectMake(x, y, width, height);
middleBorder.backgroundColor = UIColor.CGColor;
[myView.layer addSublayer:middleBorder];

方法二：使用UIImageView(不便于更改)

 1 - (void)drawLineWithPoint:(CGPoint) startPoint toPoint:(CGPoint)toPoint
 2 {
 3         CGSize screenSize = [[UIScreen mainScreen] applicationFrame].size;
 4
 5         UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, screenSize.width, screenSize.height)];
 6         //    UIImageView *imageView = [[UIImageView alloc] init];
 7         //    imageView.frame = self.contentView.frame;
 8         [self.contentView addSubview:imageView];
 9
10         UIGraphicsBeginImageContext(imageView.frame.size);
11         [imageView.image drawInRect:CGRectMake(0, 0, imageView.frame.size.width, imageView.frame.size.height)];
12
13         //获得处理的上下文
14         CGContextRef context = UIGraphicsGetCurrentContext();
15
16         //指定直线样式
17         CGContextSetLineCap(context, kCGLineCapSquare);
18
19         //直线宽度
20         CGContextSetLineWidth(context, 1.0);
21
22         //设置颜色
23         // red:166/255.0 green:177/255.0 blue:186/255.0
24         CGContextSetRGBStrokeColor(context, 246.0/255.0, 247.0/255.0, 247.0/255.0, 1.0);
25
26         //开始绘制
27         CGContextBeginPath(context);
28
29         //画笔移动到点(31,170)
30         CGContextMoveToPoint(context, startPoint.x, startPoint.y);
31
32         //下一点
33         CGContextAddLineToPoint(context, toPoint.x, toPoint.y);
34
35         //绘制完成
36         CGContextStrokePath(context);
37
38         imageView.image = UIGraphicsGetImageFromCurrentImageContext();
39         UIGraphicsEndImageContext();
40
41         //    NSLog(@"%f, %f", imageView.frame.size.width, imageView.frame.size.height);
42 }