Question

my code is like this:

// layer
highlightLayer = [[CALayer alloc]init];
highlightLayer.frame = CGRectMake(0, 420, 320, 11);
highlightLayer.backgroundColor = [UIColor greenColor].CGColor;

CALayer *contentLayer = [[CALayer alloc]init];
contentLayer.frame = CGRectMake(0, 420, 80, 11);
contentLayer.backgroundColor = [UIColor redColor].CGColor;

[highlightLayer addSublayer:contentLayer];
[contentLayer release];

but this sublayer does not appear. i don’t know why.

Answer 1

Because contentLayer’s frame is outside highlightLayer’s bounds (0, 0, 320, 11). contentLayer’s frame is expressed in highlightLayer’s coordinate system. I think you should simply adjust contentLayer’s frame origin.