做iOS的二維碼掃描，有兩個第三方庫可以選擇，ZBar和ZXing。今天要介紹的是iOS7.0後AVFoundation框架提供的原生二維碼掃描。

首先需要添加AVFoundation.framework框架到你工程中build phase的"Link Binary With Libraries"之下，然後就可以開始了。

一、做好准備工作，搭建UI

UI效果如圖

IBOutlet、IBAction如下：

@property (weak, nonatomic) IBOutlet UIView *viewPreview;
@property (weak, nonatomic) IBOutlet UILabel *lblStatus;
@property (weak, nonatomic) IBOutlet UIButton *startBtn;
- (IBAction)startStopReading:(id)sender;

接下來就都是代碼的事情了

二、控制器ViewController.h

首先導入AVFoundation框架

#import <AVFoundation/AVFoundation.h>

然後控制器實現 AVCaptureMetadataOutputObjectsDelegate協議

@interface ViewController ()<AVCaptureMetadataOutputObjectsDelegate>

整體property如下：

@property (strong, nonatomic) UIView *boxView;
@property (nonatomic) BOOL isReading;
@property (strong, nonatomic) CALayer *scanLayer;
-(BOOL)startReading;
-(void)stopReading;

//捕捉會話

@property (nonatomic, strong) AVCaptureSession *captureSession;

//展示layer

@property (nonatomic, strong) AVCaptureVideoPreviewLayer *videoPreviewLayer;

然後在ViewDidLoad方法中初始化

- (void)viewDidLoad {
  [super viewDidLoad];

  _captureSession = nil;
   _isReading = NO;
  
}

接下來實現startReading方法（這可就是重點咯）

- (BOOL)startReading {
 NSError *error;
 //1.初始化捕捉設備（AVCaptureDevice），類型為AVMediaTypeVideo
 AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
 //2.用captureDevice創建輸入流
 AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];
 if (!input) {
  NSLog(@"%@", [error localizedDescription]);
  return NO;
 }
 //3.創建媒體數據輸出流
 AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];
 //4.實例化捕捉會話
 _captureSession = [[AVCaptureSession alloc] init];
 //4.1.將輸入流添加到會話
 [_captureSession addInput:input];
 //4.2.將媒體輸出流添加到會話中
 [_captureSession addOutput:captureMetadataOutput];
 //5.創建串行隊列，並加媒體輸出流添加到隊列當中
 dispatch_queue_t dispatchQueue;
 dispatchQueue = dispatch_queue_create("myQueue", NULL);
 //5.1.設置代理
 [captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];
 //5.2.設置輸出媒體數據類型為QRCode
 [captureMetadataOutput setMetadataObjectTypes:[NSArray arrayWithObject:AVMetadataObjectTypeQRCode]];
 //6.實例化預覽圖層
 _videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];
 //7.設置預覽圖層填充方式
 [_videoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
 //8.設置圖層的frame
 [_videoPreviewLayer setFrame:_viewPreview.layer.bounds];
 //9.將圖層添加到預覽view的圖層上
 [_viewPreview.layer addSublayer:_videoPreviewLayer];
 //10.設置掃描范圍
 captureMetadataOutput.rectOfInterest = CGRectMake(0.2f, 0.2f, 0.8f, 0.8f);
 //10.1.掃描框
 _boxView = [[UIView alloc] initWithFrame:CGRectMake(_viewPreview.bounds.size.width * 0.2f, _viewPreview.bounds.size.height * 0.2f, _viewPreview.bounds.size.width - _viewPreview.bounds.size.width * 0.4f, _viewPreview.bounds.size.height - _viewPreview.bounds.size.height * 0.4f)];
 _boxView.layer.borderColor = [UIColor greenColor].CGColor;
 _boxView.layer.borderWidth = 1.0f;
 [_viewPreview addSubview:_boxView];
 //10.2.掃描線
 _scanLayer = [[CALayer alloc] init];
 _scanLayer.frame = CGRectMake(0, 0, _boxView.bounds.size.width, 1);
 _scanLayer.backgroundColor = [UIColor brownColor].CGColor;
 [_boxView.layer addSublayer:_scanLayer];
 NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:0.2f target:self selector:@selector(moveScanLayer:) userInfo:nil repeats:YES];
 [timer fire];

 //10.開始掃描
 [_captureSession startRunning];
 return YES;
}

實現AVCaptureMetadataOutputObjectsDelegate協議方法

#pragma mark - AVCaptureMetadataOutputObjectsDelegate
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
 //判斷是否有數據
 if (metadataObjects != nil && [metadataObjects count] > 0) {
  AVMetadataMachineReadableCodeObject *metadataObj = [metadataObjects objectAtIndex:0];
  //判斷回傳的數據類型
  if ([[metadataObj type] isEqualToString:AVMetadataObjectTypeQRCode]) {
   [_lblStatus performSelectorOnMainThread:@selector(setText:) withObject:[metadataObj stringValue] waitUntilDone:NO];
   [self performSelectorOnMainThread:@selector(stopReading) withObject:nil waitUntilDone:NO];
   _isReading = NO;
  }
 }
}

實現計時器方法moveScanLayer:(NSTimer *)timer

- (void)moveScanLayer:(NSTimer *)timer
{
 CGRect frame = _scanLayer.frame;
 if (_boxView.frame.size.height < _scanLayer.frame.origin.y) {
  frame.origin.y = 0;
  _scanLayer.frame = frame;
 }else{
  frame.origin.y += 5;
  [UIView animateWithDuration:0.1 animations:^{
   _scanLayer.frame = frame;
  }];
 }
}

實現開始和停止方法

- (IBAction)startStopReading:(id)sender {
  if (!_isReading) {
   if ([self startReading]) {
    [_startBtn setTitle:@"Stop" forState:UIControlStateNormal];
    [_lblStatus setText:@"Scanning for QR Code"];
   }
  }
  else{
   [self stopReading];
   [_startBtn setTitle:@"Start!" forState:UIControlStateNormal];
  }
  _isReading = !_isReading;
}
-(void)stopReading{
 [_captureSession stopRunning];
 _captureSession = nil;
 [_scanLayer removeFromSuperlayer];
 [_videoPreviewLayer removeFromSuperlayer];
}

以上內容就是本文給大家介紹ios原生二維碼掃描的全部內容，希望大家喜歡。