当UIView的尺寸类应用，对于一个UIView直接从XIB装入？

Question

I'm initting a UIView with a xib, programatically:

- (id)initWithFrame:(CGRect)frame
{
    self = [[[NSBundle mainBundle] loadNibNamed:@"MyViewNib" owner:self options:nil] objectAtIndex:0];
    if (self)
    {
        //perform setup of various components

        return self;
    }
}

This view uses size classes for Any Width, Any Height, and Any Width, Compact Height.

I have a UIButton in a xib that I need to put a circle in the background of, like so:

self.closeButton.layer.cornerRadius = self.closeButton.frame.size.width / 2.0f;
self.closeButton.layer.backgroundColor = [UIColor colorWithWhite:164.0f / 255.0f alpha:1.0f].CGColor;

If I try setting the button's corner radius in the init function when I'm on a device using Any Width, Compact Height, the label's frame is still set to the Any Width, Any Height value. I've also tried overriding layoutSubviews and setting the value there, with no luck. It appears that the size class constraints are applied after layoutSubviews without another call to layoutSubviews, since the other components appear on-screen correctly.

So, I'm wondering if there's a good entry point for me to catch where the size classes are applied, so that I can set the background corner radius of the button correctly. I could just set the button up programmatically, but I'd like to figure out how to do this since it will probably come up again in the process of converting to size classes.

Answer 1

在您的xib类中-(void)awakeFromNib;

Answer 2

This works if I put it at the end of the init function:

 [self performSelector:@selector(updateButtonBackground) withObject:nil afterDelay:.001];

Apparently by this point the constraints have been set up with the size classes. It's certainly non-ideal though, so if anyone has an answer that's event-driven or involves view "lifecycle" (as far as that applies to UIView) I'll accept that...

Answer 3

How about doing this?

-(void)layoutSubviews
{
    [super layoutSubviews];
self.closeButton.layer.cornerRadius = self.closeButton.frame.size.width / 2.0f;
self.closeButton.layer.backgroundColor = [UIColor colorWithWhite:164.0f / 255.0f alpha:1.0f].CGColor;
//more of your changes
[self layoutIfNeeded]; // You can remove this line if it works without it for you..
}

Answer 4

I know this thread is old, but I see no good answer here.

Size classes are defined in traitCollectionDidChange: method. You can't ensure that traitCollection is set in initWithFrame: or awakeFromNib: . So set your corner radius in traitCollectionDidChange: method based on the view size classes.

Answer 5

You need to apply the corner radius in viewDidLayoutSubviews . It is at this point that you know the bounds of the button have been established.

You can see an example on my blog .