CALayer - 3

来源：互联网发布：haproxy acl 端口复用编辑：程序博客网时间：2024/06/05 08:53

前面稍稍介绍了一些CALayer的显示上的属性，这里总结几个实用的使用例子：

自定义UIView的时候设置底层的layer：

@implementation ContainerView- (instancetype)initWithFrame:(CGRect)frame{    if(!(self = [super initWithFrame:frame]))    {        return nil;    }        CALayer *styleLayer = [[CALayer alloc] init];    styleLayer.cornerRadius = 4;    styleLayer.shadowColor= [[UIColor blackColor] CGColor];    styleLayer.shadowOffset = CGSizeMake(0, 0);    styleLayer.shadowOpacity = 0.5;    styleLayer.borderWidth = 1;    styleLayer.borderColor = [[UIColor whiteColor] CGColor];    //将图层缩小显示    styleLayer.frame = CGRectInset(self.bounds, 12, 12);    [self.layer addSublayer:styleLayer];    //用于释放内存    self.styleLayer = styleLayer;    return self;}@end

CALayer的层树类似于UIView的视图树，你可以访问子层和父层：

    //访问子层    NSLog(@"star - %@", self.view.layer.sublayers);        CALayer *layer=[CALayer layer];        layer.backgroundColor=[UIColor brownColor].CGColor;    layer.bounds=CGRectMake(0, 0, 200, 200);    layer.position=CGPointMake(100, 100);        [self.view.layer addSublayer:layer];        NSLog(@"end - %@",self.view.layer.sublayers);        NSLog(@"First one : %@", self.view.layer.sublayers[0]);        //访问父层    NSLog(@"SuperLayer is : %@", layer.superlayer);

后面会介绍一些作为动画效果的CALayer使用，期待！

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