CATiledLayer高于正常CALayer

Question

我正在尝试在一个层上添加两个子层。一个图层应该充当(快速渲染)背景，而另一个图层( CATiledLayer)应该显示其他内容。但是，CATiledLayer不会出现在前面。普通的CALayer总是隐藏CATiledLayer。当我删除这行时

[self.layer addSublayer:lowRes];

CATiledLayer可见。但背景并没有偏离轨道。

下面是相关的代码部分

tiledLayer = [CATiledLayer layer];
//tiledLayer.delegate = self;
tiledLayer.tileSize = CGSizeMake(800.0, 800.0);
tiledLayer.levelsOfDetail = 4;
tiledLayer.levelsOfDetailBias = 4;
tiledLayer.frame = pageRect;
tiledLayer.zPosition = 2;
[tiledLayer setNeedsLayout];
[tiledLayer retain];

CALayer * lowRes = [CALayer layer];
lowRes.frame = tiledLayer.frame;
lowRes.zPosition = 1;
lowRes.contents = (id) [UIImage imageNamed:@"krant.jpg"].CGImage;
[self.layer addSublayer:tiledLayer];    
[self.layer addSublayer:lowRes];

如何使CALayer上的CATiledLayer可见？提前谢谢。

Answer 1

是否已尝试反转addSubLayer调用？

[self.layer addSublayer:lowRes];

[self.layer addSublayer:tiledLayer];