Swift - 二维码QRCode的读取

1，直接读取图片中的二维码

使用 CIDetector可以很方便的检测并读取二维码。下面是一个从 UIImage中读取二维码的样例，我们要把图片上所有的二维码信息都打印出来。

代码如下：

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import UIKit class ViewController : UIViewController { override func viewDidLoad() { super .viewDidLoad() let qrcodeImg = UIImage (named: "codeBg.png" ) ciImage: CIImage = CIImage (image:qrcodeImg!)! context = CIContext (options: nil ) detector: CIDetector (ofType: CIDetectorTypeQRCode , context: context,options: [ CIDetectorAccuracy CIDetectorAccuracyHigh ]) features=detector.featuresInImage(ciImage) print ( "扫描到二维码个数：\(features.count)" ) //遍历所有的二维码，并框出 for feature in features as ! [ CiqrCodeFeature ] { (feature.messageString) } } didReceiveMemoryWarning() { .didReceiveMemoryWarning() } }

控制台输出如下：

扫描到二维码个数：2
http://www.hangge.com
http://www.hangge.com

可以看到两个二维码都成功的读取到了。

（注：这个我原来用模拟器一直检测不到二维码，使用真机调试就没问题。 感谢网友“落叶”的提醒，模拟器选iphone5s及以上设备也是可以检测到的。）

2，从相册中选择图片读取二维码

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import UIKit class ViewController : UIViewController ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas, UIImagePickerControllerDelegate ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas, UINavigationControllerDelegate { override func viewDidLoad() { super .viewDidLoad() } //选取相册 @IBAction fromAlbum(sender: AnyObject ) { //判断设置是否支持图片库 if UIImagePickerController .isSourceTypeAvailable(. PhotoLibrary ){ //初始化图片控制器 let picker = UIImagePickerController () //设置代理 picker.delegate = self //指定图片控制器类型 picker.sourceType = UIImagePickerControllerSourceType . PhotoLibrary //弹出控制器，显示界面 self .presentViewController(picker,animated: true ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas,completion: { () -> Void in }) } else { print ( "读取相册错误" ) } } //选择图片成功后代理 imagePickerController(picker: ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas, didFinishPickingMediawithInfo info: [ String : ]) { //获取选择的原图 image = info[ UIImagePickerControllerOriginalImage ] as ! UIImage //二维码读取 ciImage: CIImage = CIImage (image:image)! context = CIContext (options: nil ) detector: CIDetector (ofType: CIDetectorTypeQRCode ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas, ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:auto!important; background:none rgb(249,options: [ CIDetectorAccuracy CIDetectorAccuracyHigh ]) features=detector.featuresInImage(ciImage) "扫描到二维码个数：\(features.count)" ) //遍历所有的二维码，并框出 for feature in features ! [ CiqrCodeFeature ] { (feature.messageString) } //图片控制器退出 picker.dismissViewControllerAnimated( ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas,completion: { () -> Void in }) } didReceiveMemoryWarning() { .didReceiveMemoryWarning() } }

3，使用摄像头扫描读取二维码
（1）扫描主要使用的是 AVFoundation，用起来方便简单
（2）通过 AVCaptureMetadataOutput的 rectOfInterest属性，可以设置探测探测区域。同时给这个探测区域添加个方框，只有在框中的二维码才会被扫描到。

效果图如下：

代码如下：

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import UIKit AVFoundation class ViewController : UIViewController ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas, AVCaptureMetadataOutputObjectsDelegate ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas, UIAlertViewDelegate { var scanRectView: UIView ! device: AVCaptureDevice ! input: AVCaptureDeviceInput ! output: AVCaptureMetadataOutput ! session: AVCaptureSession ! preview: AVCaptureVideoPreviewLayer ! override func viewDidLoad() { super .viewDidLoad() } //通过摄像头扫描 @IBAction fromCamera(sender: AnyObject ) { do{ self .device = AVCaptureDevice .defaultDeviceWithMediaType( AVMediaTypeVideo ) .input = try (device: device) .output = AVCaptureMetadataOutput () output.setMetadataObjectsDelegate( ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas,queue: dispatch_get_main_queue()) .session = () if UIScreen .mainScreen().bounds.size.height<500 { .session.sessionPreset = AVCaptureSessionPreset640x480 } else { AVCaptureSessionPresetHigh } .session.addInput( .input) .session.addOutput( .output) .output.MetadataObjectTypes = [ AVMetadataObjectTypeQRCode ] //计算中间可探测区域 let windowSize: CGSize = .mainScreen().bounds.size; scanSize: CGSizeMake (windowSize.width*3/4, windowSize.width*3/4); scanRect: CGRect = CGRectMake ((windowSize.width-scanSize.width)/2, (windowSize.height-scanSize.height)/2,scanSize.width,scanSize.height); //计算rectOfInterest 注意x,y交换位置 scanRect = (scanRect.origin.y/windowSize.height, scanRect.origin.x/windowSize.width, scanRect.size.height/windowSize.height, scanRect.size.width/windowSize.width); //设置可探测区域 .output.rectOfInterest = scanRect .preview = AVCaptureVideoPreviewLayer (session: .session) .preview.videoGravity = AVLayerVideoGravityResizeAspectFill .preview.frame = .mainScreen().bounds .view.layer.insertSublayer( .preview,atIndex:0) //添加中间的探测区域绿框 .scanRectView = UIView (); .view.addSubview( .scanRectView) .scanRectView.frame = CGRectMake (0,scanSize.height); .scanRectView.center = CGPointMake ( CGRectGetMidX ( UIScreen .mainScreen().bounds), CGRectGetMidY .mainScreen().bounds)); .scanRectView.layer.borderColor = UIColor .greenColor(). CGColor .scanRectView.layer.borderWidth = 1; //开始捕获 .session.startRunning() }catch _ as NSError { //打印错误消息 errorAlert = UIAlertView (title: "提醒" ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas, message: "请在iPhone的\"设置-隐私-相机\"选项中,允许本程序访问您的相机" ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas, delegate: ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas, cancelButtonTitle: "确定" ) errorAlert.show() } } //摄像头捕获 captureOutput(captureOutput: AVCaptureOutput !, didOutputMetadataObjects MetadataObjects: [ AnyObject ]!, fromConnection connection: AVCaptureConnection !) { stringValue: String ? if MetadataObjects.count > 0 { MetadataObject = MetadataObjects[0] as ! AVMetadataMachineReadableCodeObject stringValue = MetadataObject.stringValue stringValue != nil { .session.stopRunning() } } .session.stopRunning() //输出结果 alertView = UIAlertView "二维码" ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas,message: stringValue, ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:0px 1em!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; min-height:auto!important; background:none rgb(249,cancelButtonTitle: ) alertView.show() } //消息框确认后消失 alertView(alertView: ottom:auto!important; float:none!important; height:auto!important; left:auto!important; line-height:1.5em!important; margin:0px!important; overflow:visible!important; padding:1px 0px!important; position:static!important; right:auto!important; top:auto!important; vertical-align:baseline!important; width:auto!important; font-family:Consolas,willdismissWithButtonIndex buttonIndex: Int ) { //继续扫描 .session.startRunning() } didReceiveMemoryWarning() { .didReceiveMemoryWarning() } }

原文出自： www.hangge.com 转载请保留原文链接： http://www.hangge.com/blog/cache/detail_915.html