Some sort of “global” for IBDesignables?

Question

In storyboard have a UIView, with a constraint for example \"0.1\" proportional height.

Imagine you have a similar constraint \"0.1\", on views in many different sce

Answer 1

I can't think of a way to make IB update all "instances" at design time when a single instance has a property value change (And I think this would generally be undesired and non-standard behavior). I'm fairly certain it can't be done because I don't think IB keeps an instance of your custom view in memory for the duration of the IB session. I think what it does is instantiate the view, set properties on it, snapshot it for rendering, then releases it.

It should be possible to set up properties that set "default" values to be used by future instances of your view. We can achieve this by storing "default" values in NSUserDefaults (XCode's), and reading the default value inside initWithFrame:, which IB will call to initialize a new instance. We can gate all this default stuff using #if TARGET_INTERFACE_BUILDER so it doesn't show up at runtime on the device.

IB_DESIGNABLE
@interface CoolView : UIView

@property (strong, nonatomic) IBInspectable UIColor* frameColor;

#if TARGET_INTERFACE_BUILDER
@property (strong, nonatomic) IBInspectable UIColor* defaultFrameColor;
#endif

@end

@implementation CoolView

- (id) initWithFrame:(CGRect)frame
{
    self = [super initWithFrame: frame];
    if ( self != nil ) {

#if TARGET_INTERFACE_BUILDER
        NSData *colorData = [[NSUserDefaults standardUserDefaults] objectForKey: @"defaultCoolViewFrameColor"];
        if ( colorData != nil ) {
            self.frameColor = [NSKeyedUnarchiver unarchiveObjectWithData: colorData];;
        }
#endif

    }
    return self;
}

- (void) drawRect:(CGRect)rect
{
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetLineWidth(context, 10);
    CGRect f = CGRectInset(self.bounds, 10, 10);
    [self.frameColor set];
    UIRectFrame(f);
}

#if TARGET_INTERFACE_BUILDER
- (void) setDefaultFrameColor:(UIColor *)defaultFrameColor
{
    _defaultFrameColor = defaultFrameColor;

    NSData *colorData = [NSKeyedArchiver archivedDataWithRootObject: defaultFrameColor];
    [[NSUserDefaults standardUserDefaults] setObject:colorData forKey:@"defaultCoolViewFrameColor"];
}
#endif

@end

You could probably get closer to your original goal (updating all "instances" in IB) if you're okay with forcing IB to reload your xib/storyboard file altogether. To do this you'd likely have to use the technique above and extend it to include code in a custom initWithCoder: method on your view.

Possibly possibly you could get really tricky and try to "touch" the xib file that is being edited, and that might prompt IB to reload?