iOS rounded UITextField with shadow

Question

I would like to add a shadow effect to my UITextField currently what I'm achieving is this:
As you can see the shadow is not rounded in the corners. My code:

        mNickname.layer.borderWidth = 1
        mNickname.layer.borderColor = UIColor.whiteColor().CGColor
        mNickname.layer.cornerRadius = 3

        mNickname.layer.masksToBounds = false
        mNickname.layer.shadowRadius = 3.0
        mNickname.layer.shadowColor = UIColor.blackColor().CGColor
        mNickname.layer.shadowOffset = CGSizeMake(1.0, 1.0)
        mNickname.layer.shadowOpacity = 1.0

Answer 1

Ok, I found the problem. Turns out that I was using rectangle border:

The correct one should be:

And the code is:

mNickname.layer.masksToBounds = false
mNickname.layer.shadowRadius = 3.0
mNickname.layer.shadowColor = UIColor.blackColor().CGColor
mNickname.layer.shadowOffset = CGSizeMake(1.0, 1.0)
mNickname.layer.shadowOpacity = 1.0

Result:

Answer 2

try this, code is in objective C, but same for swift

self.textField.layer.shadowColor = [[UIColor blackColor] CGColor];
    self.textField.layer.shadowOffset = CGSizeMake(0.0, 1.0);
    self.textField.layer.shadowOpacity = 1;
    self.textField.layer.shadowRadius = 0.0;