畫直線

方法一(推薦)：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(不便於更改)

 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         //得到處理的上下文
14         CGContextRef context = UIGraphicsGetCurrentContext();
15             
16         //指定直線樣式
17         CGContextSetLineCap(context, kCGLineCapSquare);
18             
19         //直線寬度
20         CGContextSetLineWidth(context, 1.0);
21             
22         //設置顏色
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         //開始繪製
27         CGContextBeginPath(context);
28             
29         //畫筆移動到點(31,170)
30         CGContextMoveToPoint(context, startPoint.x, startPoint.y);
31             
32         //下一點
33         CGContextAddLineToPoint(context, toPoint.x, toPoint.y);
34             
35         //繪製完成
36         CGContextStrokePath(context);
37             
38         imageView.image = UIGraphicsGetImageFromCurrentImageContext();
39         UIGraphicsEndImageContext();
40             
41         //    NSLog(@"%f, %f", imageView.frame.size.width, imageView.frame.size.height);
42 }