Rajiev

Sometimes you just want to load a pdf in a UIWebView, so here’s an extension to help you. A little bit of encapsulation can make the world of difference in readability and maintainability.

extension UIWebView {
    func loadPDF(name:String!) {
        let termsPath:String? = NSBundle.mainBundle().pathForResource(name, ofType: "pdf")!
        let url = NSURL(fileURLWithPath: termsPath!)
        let pdfRequest = NSURLRequest(URL: url!)
        self.loadRequest(pdfRequest)
    }
}

Usage:

self.webView.loadPDF("Terms")

Here’s an extension to UILabel that kerns it’s text with a specified kerning value.

extension UILabel {
    func kern(kerningValue:CGFloat) {
        self.attributedText =  NSAttributedString(string: self.text ?? "", attributes: [NSKernAttributeName:kerningValue, NSFontAttributeName:font, NSForegroundColorAttributeName:self.textColor])
    }
}

Usage:

mylabel.kern(1.5)

This extension to UIButton kerns the text in it’s titleLabel property.

extension UIButton {
    func kern(kerningValue:CGFloat) {
        let attributedText =  NSAttributedString(string: self.titleLabel!.text!, attributes: [NSKernAttributeName:kerningValue, NSFontAttributeName:self.titleLabel!.font, NSForegroundColorAttributeName:self.titleLabel!.textColor])
        self.setAttributedTitle(attributedText, forState: UIControlState.Normal)
    }
}

Usage:

mybutton.kern(1.5)

Note, as of XCode 6.2, the UIButton type must be custom so that the UIButton is resized with the kerned text. Resizing behavior occurs without a call to sizeToFit() or invalidateIntrinsicContentSize().

Here is an extension to UIImage that adds a public method called resize(size:CGSize, completionHandler:(resizedImage:UIImage, data:NSData)->()). The image is resized on a global concurrent queue and the completion handler is called on the main queue with the new UIImage and image data. Good for resizing images before sending them to a server. The jpeg compression ratio should probably also be parameterized! Enjoy!

extension UIImage {
    public func resize(size:CGSize, completionHandler:(resizedImage:UIImage, data:NSData)->()) {
        dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INITIATED, 0), { () -> Void in
            var newSize:CGSize = size
            let rect = CGRectMake(0, 0, newSize.width, newSize.height)
            UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0)
            self.drawInRect(rect)
            let newImage = UIGraphicsGetImageFromCurrentImageContext()
            UIGraphicsEndImageContext()
            let imageData = UIImageJPEGRepresentation(newImage, 0.5)
            dispatch_async(dispatch_get_main_queue(), { () -> Void in
                completionHandler(resizedImage: newImage, data:imageData)
            })
        })
    }
}

Apple, Y is this so poorly documented?

1. Add a key to your app-info.plist file called UIApplicationOpenSettingsURLString

2. Set the value of this key to “app-settings:”

3. In your code, access this value as a global constant:

NSString *const UIApplicationOpenSettingsURLString

in Objective-C, and

let UIApplicationOpenSettingsURLString: NSString!

in Swift

4. Use this global constant like so :

[UIApplication sharedApplication] openURL:[NSURL URWithString: UIApplicationOpenSettingsURLString]]

in Objective C and

UIApplication.sharedApplication().openURL(NSURL(UIApplicationOpenSettingsURLString))

in Swift.

Use canOpenURL: to test if this is possible during run time. It is not possible on iOS 7. I also wonder if there are paths you can add after “app-settings:” to open specific app settings screens such as privacy. Please leave a comment if you have any information on this.