YIVariableViewSize 1.0.2

Layout subviews first, then its container. Not using AutoLayout, works on iOS5+.

(developed in #objectivechackathon Put Objective C Back On The Map)

How to use

YIVariableViewSize is actually an abstract concept written as ObjC-protocol style. Thus, your job is to conform your UIView subclass to <YIVariableViewSize> protocol and implement its methods something like this:

- (CGSize)sizeThatFits:(CGSize)size
{
    [self resizeSubviewsWithFittingSize:size];
    [self positionSubviews];

    size.height = self.mostBottomVisibleSubview.bottom + self.paddingBottomForVariableViewSize;

    return size;
}

- (void)layoutSubviews
{
    [super layoutSubviews];
    [self positionSubviews];  // don't resize, just set origin
}

// change subview's frame.size & drawing contents
- (void)resizeSubviewsWithFittingSize:(CGSize)fittingSize
{
    [self.subview1 sizeToFitWithMaxSize:fittingSize];
    [self.subview2 sizeToFitWithMaxSize:fittingSize];
}

// change subview's frame.origin
- (void)positionSubviews
{
    self.subview2.top = self.subview1.bottom;
}

- (CGFloat)paddingBottomForVariableViewSize
{
    return 10;
}

Notice that -sizeThatFits: actually calculates subview's size, position, and lastly paddingBottom(Right), where -layoutSubviews will only handle their positioning. By doing so, we can split the resizing and positioning code, and never try to resize subview's content on -layoutSubviews, which is performance-critical.

So far so good. But you can even omit writing -sizeThatFits: and -layoutSubviews if you call [YIVariableViewSize install] in your AppDelegate.

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    [YIVariableViewSize install];
    return YES;
}

Dependencies

• JRSwizzle 1.0
• ViewUtils 1.1

License

YIVariableViewSize is available under the Beerware license.

If we meet some day, and you think this stuff is worth it, you can buy me a beer in return.