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iOS:原生二维码扫描

  做iOS的二维码扫描,有两个第三方库可以选择,ZBar和ZXing。今天要介绍的是iOS7.0后AVFoundation框架提供的原生二维码扫描。

首先需要添加AVFoundation.framework框架到你工程中build phase的"Link Binary With Libraries"之下,然后就可以开始了。

  一、做好准备工作,搭建UI

  UI效果如图技术分享

  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;

 

  接下来就都是代码的事情了

  二、控制器ViewController.h

  首先导入AVFoundation框架

#import <AVFoundation/AVFoundation.h>

  然后控制器实现AVCaptureMetadataOutputObjectsDelegate协议

@interface ViewController ()<AVCaptureMetadataOutputObjectsDelegate>

  整体property如下:

@property (strong, nonatomic) UIView *boxView;@property (nonatomic) BOOL isReading;@property (strong, nonatomic) CALayer *scanLayer;-(BOOL)startReading;-(void)stopReading;//捕捉会话@property (nonatomic, strong) AVCaptureSession *captureSession;//展示layer@property (nonatomic, strong) AVCaptureVideoPreviewLayer *videoPreviewLayer;

  然后在ViewDidLoad方法中初始化

- (void)viewDidLoad {    [super viewDidLoad];    _captureSession = nil;     _isReading = NO;    }

  接下来实现startReading方法(这可就是重点咯)

- (BOOL)startReading {    NSError *error;        //1.初始化捕捉设备(AVCaptureDevice),类型为AVMediaTypeVideo    AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];        //2.用captureDevice创建输入流    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];    if (!input) {        NSLog(@"%@", [error localizedDescription]);        return NO;    }        //3.创建媒体数据输出流    AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];        //4.实例化捕捉会话    _captureSession = [[AVCaptureSession alloc] init];        //4.1.将输入流添加到会话    [_captureSession addInput:input];        //4.2.将媒体输出流添加到会话中    [_captureSession addOutput:captureMetadataOutput];        //5.创建串行队列,并加媒体输出流添加到队列当中    dispatch_queue_t dispatchQueue;    dispatchQueue = dispatch_queue_create("myQueue", NULL);    //5.1.设置代理    [captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];        //5.2.设置输出媒体数据类型为QRCode    [captureMetadataOutput setMetadataObjectTypes:[NSArray arrayWithObject:AVMetadataObjectTypeQRCode]];        //6.实例化预览图层    _videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];        //7.设置预览图层填充方式    [_videoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];        //8.设置图层的frame    [_videoPreviewLayer setFrame:_viewPreview.layer.bounds];        //9.将图层添加到预览view的图层上    [_viewPreview.layer addSublayer:_videoPreviewLayer];        //10.设置扫描范围    captureMetadataOutput.rectOfInterest = CGRectMake(0.2f, 0.2f, 0.8f, 0.8f);        //10.1.扫描框    _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.扫描线    _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.开始扫描 [_captureSession startRunning]; return YES;}

  实现AVCaptureMetadataOutputObjectsDelegate协议方法

#pragma mark - AVCaptureMetadataOutputObjectsDelegate- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{    //判断是否有数据    if (metadataObjects != nil && [metadataObjects count] > 0) {        AVMetadataMachineReadableCodeObject *metadataObj = [metadataObjects objectAtIndex:0];        //判断回传的数据类型        if ([[metadataObj type] isEqualToString:AVMetadataObjectTypeQRCode]) {            [_lblStatus performSelectorOnMainThread:@selector(setText:) withObject:[metadataObj stringValue] waitUntilDone:NO];                        [self performSelectorOnMainThread:@selector(stopReading) withObject:nil waitUntilDone:NO];            _isReading = NO;        }    }}

 

  实现计时器方法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;        }];    }}

  实现开始和停止方法

- (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];}

  大功告成

  示例源码地址:https://github.com/WuKongCoo1/QRCodeReader

    

 

iOS:原生二维码扫描