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| − | =Swift Code snippts= | + | =Swift Code Snippts= |
| | Back To [[IOS_Swift]] | | Back To [[IOS_Swift]] |
| | ==[[Swift: Use NSUserDefaults to Store Persistence Data]]== | | ==[[Swift: Use NSUserDefaults to Store Persistence Data]]== |
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| | ==[[Swift:Using UIRefreshControl]]== | | ==[[Swift:Using UIRefreshControl]]== |
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| − | ==Example of fetching messages from Parse== | + | ==[[Swift:Using UIGestureRecognizer]]== |
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| | + | ==Swift:Example of fetching messages from Parse== |
| | https://gist.github.com/sandofsky/7134b1ff90d235901254 | | https://gist.github.com/sandofsky/7134b1ff90d235901254 |
| − | ==Auto Table Row Height==
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| − | <pre class="brush:swift">
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| − | //Auto table row height
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| − | tableView.estimatedRowHeight = 92.0
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| − | tableView.rowHeight = UITableViewAutomaticDimension
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| − | </pre>
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| − | ==Navigation between storyboards==
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| − | ===Navigate to Storyboard ID===
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| − | <pre class="brush:swift">
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| − | var vc = storyboard.instantiateViewControllerWithIdentifier("loginViewController") as UIViewController
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| − | window?.rootViewController = vc
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| − | </pre>
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| − | ===Navigate Segue by Identifier===
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| − | First, drag a segue in storyboard and give it an identifier, then in the button action (or any action you like), do:
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| − | <pre class="brush:swift">
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| − | self.performSegueWithIdentifier("loginSegue", sender: self)
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| − | </pre>
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| − | ===Get UIVewController from Navigation Controller===
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| − | Sometimes, you want to access the UIViewController from a navigation controller
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| − | <pre class="brush:swift">
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| − | var vc = storyboard?.instantiateViewControllerWithIdentifier("navigationID") as UINavigationController
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| − | var v = vc.viewControllers[0] as ViewController // [0] represents the first level UIViewController under NavigationController
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| − | </pre>
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| − | ==Notification in Swift==
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| − | Listen notification in swift
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| − | <pre class="brush:swift">
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| − | func tweetSent(notification: NSNotification) {
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| − | let newTweet:Dictionary<String, Tweet> = notification.userInfo as Dictionary<String, Tweet>
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| − | }
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| − | NSNotificationCenter.defaultCenter().addObserver(self, selector: "tweetSent:", name: "newTweetNotification", object: nil)
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| − | </pre>
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| − | Send/Post notification in swift
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| − | <pre class="brush:swift">
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| − | var userInfo: Dictionary<String, Tweet> = ["tweet": newTweet]
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| − | NSNotificationCenter.defaultCenter().postNotificationName("newTweetNotification", object: nil, userInfo: userInfo)
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| − | </pre>
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| − | Remove notification observer
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| − | <pre class="brush:swift">
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| − | deinit {
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| − | NSNotificationCenter.defaultCenter().removeObserver(self)
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| − | }
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| − | </pre>
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| − | ==Get Raw Histogram from CGImage in swift==
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| − | Credit to http://stackoverflow.com/questions/27237297/how-to-get-meaningful-ciareahistogram-output
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| − |
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| − | <pre class="brush:swift">
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| − | //dataImage is a CGImage
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| − | var imageData: CFDataRef = CGDataProviderCopyData(CGImageGetDataProvider(dataImage))
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| − | var dataInput: UnsafePointer<UInt8> = CFDataGetBytePtr(imageData)
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| − | //In swift, I have to do 2 steps. Not sure if there is any better way
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| − | var dataInputMutable = UnsafeMutablePointer<Void>(dataInput)
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| − | var height: vImagePixelCount = CGImageGetHeight(dataImage)
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| − | var width: vImagePixelCount = CGImageGetWidth(dataImage)
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| − | //Build a vImage_Buffer for next step
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| − | var vImageBuffer = vImage_Buffer(data: dataInputMutable, height: height, width: width, rowBytes: CGImageGetBytesPerRow(dataImage))
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| − | //Build the output array.
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| − | //To init a multi-dimensional UnsafeMutablePointer array. I have to do 3 steps
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| − | //First alloc sub arrays
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| − | var r = UnsafeMutablePointer<vImagePixelCount>.alloc(256)
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| − | var g = UnsafeMutablePointer<vImagePixelCount>.alloc(256)
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| − | var b = UnsafeMutablePointer<vImagePixelCount>.alloc(256)
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| − | var a = UnsafeMutablePointer<vImagePixelCount>.alloc(256)
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| − | //Then alloc main array
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| − | var histogram = UnsafeMutablePointer<UnsafeMutablePointer<vImagePixelCount>>.alloc(4)
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| − | //Set the pointer of sub arrays
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| − | histogram[0] = r
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| − | histogram[1] = g
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| − | histogram[2] = b
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| − | histogram[3] = a
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| − | //Finally, do the histogram calculation
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| − | var error:vImage_Error = vImageHistogramCalculation_ARGB8888(&vImageBuffer, histogram, 0);
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| − |
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| − | if (error == kvImageNoError) {
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| − | for var j = 0; j < 256; j++ {
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| − | let currentVal = histogram[0][j] + histogram[1][j] + histogram[2][j] //I am making a grey histogram
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| − | if currentVal > 0 {
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| − | println("j=\(j),\(currentVal)")
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| − | }
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| − | }
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| − | //delloc. MUST do this manually to prevent memory leak
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| − | r.dealloc(256)
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| − | g.dealloc(256)
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| − | b.dealloc(256)
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| − | a.dealloc(256)
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| − | histogram.dealloc(4)
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| − | } else {
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| − | println("Histogram vImage error: \(error)")
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| − | }
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| − | </pre>
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| − | ==Xcode Swift Create Custom UIColor==
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| − | <pre class="brush:swift">let swiftColor = UIColor(red: 1, green: 165/255, blue: 0, alpha: 1)</pre>
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| − |
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| − | ==UIGraphics Drawing on UIView==
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| − | ===Swift: Tutorial Drawing Graphic===
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| − | See http://www.techotopia.com/index.php/An_iOS_8_Swift_Graphics_Tutorial_using_Core_Graphics_and_Core_Image
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| − |
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| − | ===Swift: How to make UIGraphics context background transparent===
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| − | If you want to set a transparent background of the content you are drawing.
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| − | <pre class="brush:swift">
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| − | // UIGraphics draw transparent background context
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| − | @IBOutlet weak var histogramView: HistogramView!
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| − | override func viewWillAppear(animated: Bool) {
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| − | histogramView.opaque = false
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| − | histogramView.backgroundColor = UIColor.clearColor()
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| − | }
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| − | class HistogramView: UIView {
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| − | override func drawRect(rect: CGRect) {
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| − | // draw content
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| − | let context = UIGraphicsGetCurrentContext()
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| − | CGContextClearRect(context, rect)
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| − | }
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| − | }
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| − | </pre>
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| − |
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| − | ==Swift: Scale down CGImage==
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| − | <pre class="brush:swift">
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| − | func scaleDownCGImage(image: CGImage, scale: Float) -> CGImage!{
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| − | var scaleDiv = UInt(1.0 / scale)
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| − | let width = CGImageGetWidth(image) / scaleDiv
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| − | let height = CGImageGetHeight(image) / scaleDiv
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| − | let bitsPerComponent = CGImageGetBitsPerComponent(image)
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| − | let bytesPerRow = CGImageGetBytesPerRow(image)
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| − | let colorSpace = CGImageGetColorSpace(image)
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| − | let bitmapInfo = CGImageGetBitmapInfo(image)
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| − | let context = CGBitmapContextCreate(nil, width, height, bitsPerComponent, bytesPerRow, colorSpace, bitmapInfo)
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| − | CGContextSetInterpolationQuality(context, kCGInterpolationMedium)
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| − | let imgSize = CGSize(width: Int(width), height: Int(height))
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| − | CGContextDrawImage(context, CGRect(origin: CGPointZero, size: imgSize), image)
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| − | return CGBitmapContextCreateImage(context)
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| − | }
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| − | </pre>
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| − |
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| | | | |
| − | ==Swift: Convert between CGImage, CIImage and UIImage== | + | ==[[Swift:Auto Table Row Height]]== |
| − | ===Swift: Convert CIImage to CGImage===
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| − | <pre class="brush:swift">
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| − | func convertCIImageToCGImage(inputImage: CIImage) -> CGImage! {
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| − | let context = CIContext(options: nil)
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| − | if context != nil {
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| − | return context.createCGImage(inputImage, fromRect: inputImage.extent())
| + | |
| − | }
| + | |
| − | return nil
| + | |
| − | }
| + | |
| − | </pre>
| + | |
| − | ===Swift: Convert CGImage to CIImage===
| + | |
| − | <pre class="brush:swift">
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| − | func convertCGImageToCIImage(inputImage: CGImage) -> CIImage! {
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| − | var ciImage = CIImage(CGImage: inputImage)
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| − | return ciImage
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| − | }
| + | |
| − | </pre>
| + | |
| − | ===Swift: Convert CGImage or CIImage to UIImage===
| + | |
| − | <pre class="brush:swift">
| + | |
| − | UIImage(CGImage: cgImage)
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| − | UIImage(CIImage: ciImage)
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| − | </pre>
| + | |
| − | ===Swift: Convert UIImage to CIImage===
| + | |
| − | <pre class="brush:swift">
| + | |
| − | //uiImage: UIImage
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| − | //Convert to CIImage
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| − | var ciImage = CIImage(image: uiImage)
| + | |
| − | </pre>
| + | |
| − | ===Swift: Convert UIImage to CGImage===
| + | |
| − | To convert to CGImage, it requires 2 steps:
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| | | | |
| − | First convert to CIImage [[#Swift: Convert UIImage to CIImage]].
| + | ==[[Swift:Navigation between storyboards]]== |
| | | | |
| − | Then convert to CGImage [[#Swift:_Convert_CIImage_to_CGImage]]
| + | ==[[Swift:Notification Observer Using NSNotificationCenter]]== |
| | | | |
| − | ==Swift Detect Volumn Button Press== | + | ==[[Swift:Get Raw Histogram from CGImage]]== |
| − | Credit to http://stackoverflow.com/questions/28471481/swift-detect-volume-button-press
| + | |
| | | | |
| − | Detect volume button press, also hide volume HUD
| + | ==[[Swift:UIGraphics Drawing on UIView]]== |
| | | | |
| − | <pre class="brush:swift">
| + | ==[[Swift:UIGraphics Scale Down CGImage]]== |
| − | import MediaPlayer //Only for hidding Volume view
| + | |
| − | func listenVolumeButton(){
| + | |
| | | | |
| − | let audioSession = AVAudioSession.sharedInstance()
| + | ==[[Swift: Convert between CGImage, CIImage and UIImage]]== |
| − | audioSession.setActive(true, error: nil)
| + | |
| − | audioSession.addObserver(self, forKeyPath: "outputVolume", options: NSKeyValueObservingOptions.New, context: nil)
| + | |
| − | //If you want to hide Volume HUD view
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| − | var volumeView: MPVolumeView = MPVolumeView(frame: CGRectZero)
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| − | view.addSubview(volumeView)
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| − | }
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| | | | |
| − | override func observeValueForKeyPath(keyPath: String, ofObject object: AnyObject,
| + | ==[[Swift:Detect Volumn Button Press]]== |
| − | change: [NSObject : AnyObject], context: UnsafeMutablePointer<Void>) {
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| − | if keyPath == "outputVolume"{
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| − | print("got in here")
| + | |
| − | }
| + | |
| − | }
| + | |
| | | | |
| − | </pre>
| + | ==[[Swift:NSTimer scheduledTimerWithTimeInterval]]== |
