Property cannot be found on forward class object?

I have a UIView and I‘m trying to set its layer properties.

self.colorSwatch = [[UIView alloc] initWithFrame:CGRectMake(400, 150, 100, 100)];
self.colorSwatch.layer.cornerRadius = 8; 

However, when I try to access the .layer.cornerRadius property, I get a warning that says "Property ‘cornerRadius‘ cannot be found in forward class object ‘CALayer *‘.

What does this mean? Thanks

It doesn‘t know what type of object the layer property is. Add #import <QuartzCore/QuartzCore.h> to the top of your file.

You also need to add the QuartzCore framework if you didn‘t do that already.

Property cannot be found on forward class object?

原文：http://www.cnblogs.com/ghgyj/p/4059037.html