objective-c - iOS画虚线

Question

想在两个控件之间画虚线,有如下代码,不知为何不能画出来;

- (void)drawRect:(CGRect)rect {
        CGContextRef context = UIGraphicsGetCurrentContext();
        CGContextBeginPath(context);
        CGContextSetLineWidth(context, 5.0);
        CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
        CGFloat lengths[] = {10,10};
        CGContextSetLineDash(context, 0, lengths, 5);
        CGContextMoveToPoint(context, 10.0, 20.0);
        CGContextAddLineToPoint(context, 310.0,20.0);
    //    CGContextMoveToPoint(context, _strategyImageView1.frame.origin.x + 101, _strategyImageView1.frame.origin.y + 25);
    //    CGContextAddLineToPoint(context, _strategyImageView2.frame.origin.x, _strategyImageView2.frame.origin.y + 25);
        CGContextStrokePath(context);
        CGContextClosePath(context);
}

Answer 1

There is nothing wrong with the code itself, you can draw a dotted line

Answer 2

Will it be covered by other controls? Open the hierarchy page and take a look