I have tried to make an app scanning the QR code within ios 10 and Swift 3. However, my QRScannerController could not detect the QR Code but showing the camera view.
I don't understand what's wrong with the code. Here is the implement of the controller:
import UIKit
import AVFoundation
class QRScannerController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
#IBOutlet var messageLabel:UILabel!
#IBOutlet var topbar: UIView!
//TESTING
var captureSession: AVCaptureSession?
var videoPreviewLayer: AVCaptureVideoPreviewLayer?
var qrCodeFrameView: UIView?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
// Get an instance of the AVCaptureDevice class to initialize a device object and provide the video as the media type parameter
let captureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
do {
view.bringSubview(toFront: messageLabel)
view.bringSubview(toFront: topbar)
// Get an instance of the AVCaptureDeviceInput class using the previous deivce object
let input = try AVCaptureDeviceInput(device: captureDevice)
// Initialize the captureSession object
captureSession = AVCaptureSession()
// Set the input devcie on the capture session
captureSession?.addInput(input)
// Initialize a AVCaptureMetadataOutput object and set it as the input device
let captureMetadataOutput = AVCaptureMetadataOutput()
captureSession?.addOutput(captureMetadataOutput)
// Set delegate and use the default dispatch queue to execute the call back
captureMetadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
captureMetadataOutput.metadataObjectTypes = [AVMetadataObjectTypeQRCode]
//Initialise the video preview layer and add it as a sublayer to the viewPreview view's layer
videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
videoPreviewLayer?.frame = view.layer.bounds
view.layer.addSublayer(videoPreviewLayer!)
//start video capture
captureSession?.startRunning()
//Initialize QR Code Frame to highlight the QR code
qrCodeFrameView = UIView()
if let qrCodeFrameView = qrCodeFrameView {
qrCodeFrameView.layer.borderColor = UIColor.green.cgColor
qrCodeFrameView.layer.borderWidth = 2
view.addSubview(qrCodeFrameView)
view.bringSubview(toFront: qrCodeFrameView)
}
func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) {
// Check if the metadataObjects array is not nil and it contains at least one object.
if metadataObjects == nil || metadataObjects.count == 0 {
qrCodeFrameView?.frame = CGRect.zero
messageLabel.text = "No QR code is detected"
return
}
// Get the metadata object.
let metadataObj = metadataObjects[0] as! AVMetadataMachineReadableCodeObject
if metadataObj.type == AVMetadataObjectTypeQRCode {
// If the found metadata is equal to the QR code metadata then update the status label's text and set the bounds
let barCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj)
qrCodeFrameView?.frame = barCodeObject!.bounds
if metadataObj.stringValue != nil {
messageLabel.text = metadataObj.stringValue
}
}
}
} catch {
//If any error occurs, simply print it out
print(error)
return
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
Your message label is going under your view controller view. Just bring the message label to front at the end of view did load would help.
I have created a sample project and it was working fine on iPhone. Please take a look at here
Related
I am trying to implement a custom appearing/disappearing animation for a modal UIViewController in my app.
I have published the code showing this error here.
Here is the content related:
/// The view controller from which I'm trying to display the modal
class ViewController: UIViewController {
#IBAction func tapped() {
/// The modal showing
ModalTestViewController.show()
}
//...
}
/// The displayed modal
open class ModalTestViewController: TransitioningModalViewController {
init() {
super.init(nibName: "ModalTestViewController", bundle: .main)
transitioningDelegate = self
// 1. when I put transitioningDelegate here, case 1
}
public required init?(coder: NSCoder) {
fatalError()
}
open override func viewDidLoad() {
super.viewDidLoad()
// 2. if I put transitioningDelegate here, case 2
}
#IBAction func tapped() {
// a tap on the overlayView of my modal
dismiss(animated: true)
}
static func show() {
let modal = ModalTestViewController()
modal.modalPresentationStyle = .overCurrentContext
DispatchQueue.main.async {
UIApplication.shared.delegate?.window??.rootViewController?.present(modal, animated: true)
}
}
}
/// The default modal view controller, which all modals in my app should inherit
open class TransitioningModalViewController: UIViewController {
// MARK: View Properties
#IBOutlet weak var overlayView: UIView!
}
extension TransitioningModalViewController: UIViewControllerTransitioningDelegate {
public func animationController(
forPresented presented: UIViewController,
presenting: UIViewController,
source: UIViewController
) -> UIViewControllerAnimatedTransitioning? {
return TransitioningModalViewControllerPresenter()
}
public func animationController(
forDismissed dismissed: UIViewController
) -> UIViewControllerAnimatedTransitioning? {
return TransitioningModalViewControllerDismisser()
}
}
private final class TransitioningModalViewControllerPresenter: NSObject, UIViewControllerAnimatedTransitioning {
func transitionDuration(
using transitionContext: UIViewControllerContextTransitioning?
) -> TimeInterval {
return 0.5
}
func animateTransition(
using transitionContext: UIViewControllerContextTransitioning
) {
let toViewController: TransitioningModalViewController = transitionContext.viewController(
forKey: UITransitionContextViewControllerKey.to
) as! TransitioningModalViewController
let duration = transitionDuration(using: transitionContext)
toViewController.overlayView.alpha = 0.0
UIView.animate(
withDuration: duration
) {
toViewController.overlayView.alpha = 0.65
} completion: { result in
transitionContext.completeTransition(result)
}
}
}
private final class TransitioningModalViewControllerDismisser: NSObject, UIViewControllerAnimatedTransitioning {
func transitionDuration(
using transitionContext: UIViewControllerContextTransitioning?
) -> TimeInterval {
return 0.5
}
func animateTransition(
using transitionContext: UIViewControllerContextTransitioning
) {
let fromViewController: TransitioningModalViewController = transitionContext.viewController(
forKey: UITransitionContextViewControllerKey.from
) as! TransitioningModalViewController
let duration = transitionDuration(using: transitionContext)
UIView.animate(
withDuration: duration
) {
fromViewController.overlayView.alpha = 0.0
} completion: { result in
transitionContext.completeTransition(result)
}
}
}
The idea behind this is that the modal appearance should not be the usual bottom-to-top animation, but instead the overlay view should go from hidden to an alpha of 0,65.
Case 1: when I put transitioningDelegate = self in init(), the animation is killed and nothing happens.
Case 2: when I put it into the viewDidLoad(), the appearing animation is the default bottom-to-top one, but the disappearing one is the expecting one (with the overlay view vanishing).
It looks like something is wrong with the initial transitioningDelegate setting but I can't find what.
Thank you for your help!
In your original code, you are setting the delegate here:
open override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
transitioningDelegate = self
}
However, .present(...) is called before viewDidAppear(...), so the controller is presented with default slide-up animation.
Setting the delegate in init() doesn't work, because we have override the default presentation process... and the presented controller's view is never added to the view hierarchy.
This "quick fix" should do the job...
First, in ModalTestViewController, move setting the delegate to init():
init() {
super.init(nibName: "ModalTestViewController", bundle: .main)
transitioningDelegate = self
}
then, in TransitioningModalViewControllerPresenter, add these lines before the animation:
func animateTransition(
using transitionContext: UIViewControllerContextTransitioning
) {
let toViewController: TransitioningModalViewController = transitionContext.viewController(
forKey: UITransitionContextViewControllerKey.to
) as! TransitioningModalViewController
// add these lines \/
// get the "from" view controller
let fromVC = transitionContext.viewController(forKey: .from)!
// get the "to" view controller's view
let toView = transitionContext.view(forKey: .to)!
// set the frame of the "to" view to the initialFrame (the current frame) of the "from" VC
toView.frame = transitionContext.initialFrame(for: fromVC)
// get the transition container view
let container = transitionContext.containerView
// add the "to" view to the view hierarchy
container.addSubview(toView)
// add these lines /\
let duration = transitionDuration(using: transitionContext)
toViewController.overlayView.alpha = 0.0
UIView.animate(
withDuration: duration
) {
toViewController.overlayView.alpha = 0.65
} completion: { result in
transitionContext.completeTransition(result)
}
}
Personally, to make this more flexible, I would get rid of your overlayView and set the alpha on the controller's view itself.
I'm building a simple video editor for macOS: A movie file is loaded as an AVAsset, transformed by a series of CIFilters in a AVVideoComposition, and played by an AVPlayer. I present UI controls for some of the parameters of the CIFilters.
When video is playing everything is working great, I slide sliders and effects change! But when the video is paused the AVPlayerView doesn't redraw after the controls in the UI are changed.
How can I encourage the AVPlayerView to redraw the contents of the videoComposition of it's current item when it's paused?
class ViewController: NSViewController {
#objc #IBAction func openDocument(_ file: Any) { ... }
#IBOutlet weak var moviePlayerView: AVPlayerView!
var ciContext:CIContext? = CIContext(mtlDevice: MTLCreateSystemDefaultDevice()!)
var sliderValue: Double = 0.0
#IBAction func sliderMoved(_ sender: NSSlider) {
self.sliderValue = sender.doubleValue
// need to update the view here when paused
self.moviePlayerView.setNeedsDisplay(self.moviePlayerView.bounds)
// setNeedsDisplay has no effect.
}
func loadMovie(file: URL) {
let avMovie = AVMovie(url: file)
let avPlayerItem = AVPlayerItem(asset: avMovie)
avPlayerItem.videoComposition = AVVideoComposition(asset: avMovie) { request in
let output = request.sourceImage.applyingGaussianBlur(sigma: self.sliderValue)
request.finish(with: output, context: self.ciContext)
}
self.moviePlayerView.player = AVPlayer(playerItem: avPlayerItem)
}
}
It turns out re-setting the AVPlayerItem's videoComposition property will trigger the item to redraw. This works even if you set the property to it's current value: item.videoComposition = item.videoComposition. The property setter appears to have undocumented side effects.
To fix the sample code above, do this:
#IBAction func sliderMoved(_ sender: NSSlider) {
self.sliderValue = sender.doubleValue
// update the view when paused
if self.moviePlayerView.player?.rate == 0.0 {
self.moviePlayerView.player?.currentItem?.videoComposition = self.moviePlayerView.player?.currentItem?.videoComposition
}
}
Hopefully someone finds this useful!
First of all I would like to thank anyone in advance for any help I get.
I have searched far and wide across the net and cannot find a solution to my issue. My issue is with an iOS game I am building using the SpriteKit framework. I have added a background song using an SKAudioNode and it works fine initially, but when I pause and play the game within a few seconds, the music does not begin playing again. I have tried lots of things like removing the SKAudioNode when the game is paused and adding it again when the game is resumed, but nothing has worked. I have posted a snippet of my code below keeping it as relevant as possible:
class GameScene: SKScene, SKPhysicsContactDelegate {
var backgroundMusic = SKAudioNode(fileNamed: "bg.mp3")
let pauseImage = SKTexture(imageNamed: "pause.png")
var pauseButton:SKSpriteNode!
let playImage = SKTexture(imageNamed: "play2.png")
var playButton:SKSpriteNode!
override func didMoveToView(view: SKView) {
self.addChild(backgroundMusic)
// create pause button
pauseButton = SKSpriteNode(texture: pauseImage)
pauseButton.position = CGPoint(x: self.size.width - pauseButton.size.width, y: pauseButton.size.height)
pauseButton.zPosition = 1
pauseButton.name = "pauseButton"
self.addChild(pauseButton)
// create play button
playButton = SKSpriteNode(texture: playImage)
playButton.position = CGPoint(x: self.size.width - playButton.size.width, y: -playButton.size.height)
playButton.zPosition = 1
playButton.name = "playButton"
self.addChild(playButton)
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
for touch in touches {
if pauseButton.containsPoint(touch.locationInNode(self)) {
let blockOne = SKAction.runBlock({
self.pauseButton.position.y = - self.pauseButton.size.height
self.playButton.position.y = self.playButton.size.height
})
let blockTwo = SKAction.runBlock({
self.view?.paused = true
})
self.runAction(SKAction.sequence([blockOne, blockTwo]))
}
else if(playButton.containsPoint(touch.locationInNode(self))) {
self.playButton.position.y = -self.playButton.size.height
self.pauseButton.position.y = self.pauseButton.size.height
self.view?.paused = false
}
}
}
}
You'll want to look into using AVAudioPlayer and NSNotificationCenter to pass data around the game.
Start the background audio player in your actual GameViewController class.
It's better to do it this way then use SKAudioNode... That's more for sounds that are like sound effects relating to something that happened in gameplay.
By using AVAudioPlayer, the advantage is when the music is paused it's still cued up to play in it's previous spot.
This is one of the few things that will be running regardless of what's going on. So we put it in the GameViewController.
So here's an example of GameViewController code we'd need to start
import AVFoundation
var bgMusicPlayer:AVAudioPlayer?
Then in the GameViewController we make these functions as such
override func viewDidLoad() {
super.viewDidLoad()
// PlayBackgroundSound , PauseBackgroundSound will be your code to send from other "scenes" to use the audio player //
// NSNotificationCenter to pass data throughout the game //
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(GameViewController.playBackgroundSound(_:)), name: "PlayBackgroundSound", object: nil)
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(GameViewController.pauseBackgroundSound), name: "PauseBackgroundSound", object: nil)
}
func playBackgroundSound(notification: NSNotification) {
let name = notification.userInfo!["fileToPlay"] as! String
if (bgSoundPlayer != nil){
bgSoundPlayer!.stop()
bgSoundPlayer = nil
}
if (name != ""){
let fileURL:NSURL = NSBundle.mainBundle().URLForResource(name, withExtension: "mp3")!
do {
bgSoundPlayer = try AVAudioPlayer(contentsOfURL: fileURL)
} catch _{
bgSoundPlayer = nil
}
bgSoundPlayer!.volume = 1
bgSoundPlayer!.numberOfLoops = -1
// -1 will loop it forever //
bgSoundPlayer!.prepareToPlay()
bgSoundPlayer!.play()
}
}
func pauseBackgroundSound() {
if (bgSoundPlayer != nil){
bgSoundPlayer!.pause()
}
}
Then when you want to use the audio player in your pause or resume button functions.
Remember you need to have the player used in each scene.
import AVFoundation.AVAudioSession
override func didMoveToView(view: SKView) {
try! AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryAmbient)
}
Then if you want to pause or play something just use NSNotificationCenter.
// To Pause in a scene use this line of code in the function you need to pause the music
NSNotificationCenter.defaultCenter().postNotificationName("PauseBackgroundSound", object: self)
/// To Play initially or a new song .. use this line of code in the function you need to play the music
NSNotificationCenter.defaultCenter().postNotificationName("PlayBackgroundSound", object: self, userInfo: "FILE NAME OF BACKGROUND MUSIC")
I want to create A Ui TableView with a list of image link with swift 2:
for example : var images = ["link1","link2",...,linkN"]
I create a custom cell to display the image :
let cell = tableView.dequeueReusableCellWithIdentifier(CurrentFormTableView.CellIdentifiers.ImageCell, forIndexPath: indexPath) as! ImageCell
cell.urlImageView.tag = indexPath.row
cell.displayImage(images[index.row])
cell.selectionStyle = UITableViewCellSelectionStyle.None
return cell
And here I have my custom cell to load my image :
import UIKit
class ImageCell: UITableViewCell {
#IBOutlet weak var urlImageView: UIImageView!
#IBOutlet weak var loadingStatus: UIActivityIndicatorView!
override func awakeFromNib() {
super.awakeFromNib()
}
override func setSelected(selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
}
func loadImageFromUrl(url: String, view: UIImageView){
if view.image == nil {
self.startLoading()
// Create Url from string
let url = NSURL(string: url)!
// Download task:
// - sharedSession = global NSURLCache, NSHTTPCookieStorage and NSURLCredentialStorage objects.
let task = NSURLSession.sharedSession().dataTaskWithURL(url) { (responseData, responseUrl, error) -> Void in
// if responseData is not null...
if let data = responseData{
// execute in UI thread
dispatch_async(dispatch_get_main_queue(), { () -> Void in
self.stopLoading()
view.image = UIImage(data: data)
})
}
}
// Run task
task.resume()
}
}
func displayImage(imageUrl: String){
imageView?.image = nil
if imageUrl != nil && imageUrl != "" {
print(imageUrl)
loadImageFromUrl(imageUrl,view: urlImageView)
} else {
loadingStatus.hidden = true
}
}
func startLoading(){
loadingStatus.hidden = false
loadingStatus.startAnimating()
}
func stopLoading(){
loadingStatus.hidden = true
loadingStatus.stopAnimating()
}
}
The problem is that, she times the images are loading correctly, and sometimes, one image or more "override the other" so I have multiple identical images instead of see all my different images. How it is possible ? Where is my mistake ?
You're not implementing the reuse of the cells, meaning that the imageView's image of one cell will be the same as another that it was reused from, until the new image has loaded.
To prevent this, implement the -prepareForReuse: method:
override func prepareForReuse() {
super.prepareForReuse()
urlImageView.image = nil
// cancel loading
}
Furthermore, you shouldn't be doing any network-related code in the view layer, it should be done in the view controller. This will allow you to implement caching mechanisms if the image has already been downloaded for a specific cell, as well as alter the state of other views.
i.e. In your view controller:
var cachedImages = [String: UIImage]()
func cellForRow...() {
let imageURL = imageURLs[indexPath.row]
if let image = cachedImages[imageURL] {
cell.urlImageView.image = cachedImages[imageURL]
}
else {
downloadImage(indexPath, { image in
if let image = image {
cachedImages[imageURL] = image
cell.urlImageView.image = image
}
})
}
}
func downloadImage(indexPath: NSIndexPath, callback: () -> (UIImage?)) {
let task = NSURLSession.sharedSession().dataTaskWithURL(url) { (responseData, responseUrl, error) -> Void in
// if responseData is not null...
if let data = responseData {
// execute in UI thread
dispatch_async(dispatch_get_main_queue(), {
callback(UIImage(data: data))
})
}
else {
dispatch_async(dispatch_get_main_queue(), {
callback(nil)
})
}
}
// Run task
task.resume()
}
// This is in ViewController.swift
import Cocoa
class ViewController: NSViewController {
#IBOutlet weak var oneLabel: NSTextField!
override func viewDidLoad() {
super.viewDidLoad()
oneLabel.stringValue = "All is well" // Here it works
//...
}
}
// Separate Swift code file
import Cocoa
import Foundation
var si = Simulate()
class Simulate: NSViewController {
#IBOutlet weak var aLabel: NSTextField!
func simulationManager() -> Bool {
var ni: Int
var breakPoint = false
rd.simStatus = .Running
do {
if rd.rchIndex >= ld.NodeCount(.Reach) {
if InterStepConvergence() {
NextTimeStep()
if aLabel != nil { // This is always false
aLabel.stringValue = String(rd.elapsedSec)
}
else {
println("Label is nil")
}
//...
}
}
}
}
}
I am trying to set up a custom controller to update the interface while a
simulation is running. I need to show the status of the simulation. The simulation runs in a separate thread, but even if I do it in the main thread, same problem as described below.
The label text can be changed if I do it in the ViewController class as above.
But if I try to modify the text on the label in the Simulate class the label
is always nil and so it doesn't work. But the code compiles OK. What am I missing here such that the label is always nil in the Simulate class? Thanks much, in advance.