IOS 原生二维码扫描 学习笔记

先上效果图：

1.

在 iOS7 以前，在iOS中实现二维码和条形码扫描，我们所知的有，两大开源组件 ZBar 与 ZXing. 

AVFoundation无论在扫描灵敏度和性能上来说都是最优的，所以毫无疑问我们应该切换到AVFoundation，需要兼容IOS6或之前的版本可以用zbar或zxing代替。

2.

另一个提升扫描速度和性能的就是设置解析的范围，在zbar和zxing中就是scanCrop, AVFoundation中设置AVCaptureMetadataOutput 的 rectOfInterest 属性来配置解析范围。

#import "AVCaptureMetadataOutputViewController.h"
#import <AVFoundation/AVFoundation.h>

#define LINE_SCAN_TIME  3.0     // 扫描线从上到下扫描所历时间（s）

@interface AVCaptureMetadataOutputViewController ()<AVCaptureMetadataOutputObjectsDelegate>
{

     AVCaptureSession * session;//输入输出的中间桥梁
    
     UILabel *_infoLabel;
    
     CGRect mainBounds;
    
     CGRect readerFrame;
    
     CGSize viewFinderSize;
    
}

@property (nonatomic, strong) UIImageView *scanLineImageView;
@property (nonatomic, strong) NSTimer *scanLineTimer;

@end

@implementation AVCaptureMetadataOutputViewController

#pragma mark - life Cycle

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    self.title = @"二维码扫描";
    
    [self loadAVCapture];
}

- (void)viewWillAppear:(BOOL)animated
{
    self.navigationController.navigationBar.hidden = YES;
    UIApplication *application = [UIApplication sharedApplication];
    [application setStatusBarHidden:YES];
    
    [super viewWillAppear:animated];
    
    //6.启动会话
    //[self.session startRunning];
}

- (void)viewDidAppear:(BOOL)animated
{
    
    if (![self isCkeckAVdevice]) return;
        
    if (self.scanLineTimer == nil)
    {
         [self initScanLineView];
        
         [self createTimer];
    }
    
    [super viewDidAppear:YES];
}

- (void)viewWillDisappear:(BOOL)animated
{
    self.navigationController.navigationBar.hidden = NO;
    UIApplication *application = [UIApplication sharedApplication];
    [application setStatusBarHidden:NO];
    
    [super viewWillDisappear:animated];
}

#pragma mark - load AVCapture

- (void)loadAVCapture
{
    mainBounds = [[UIScreen mainScreen] bounds];
    self.view.frame = mainBounds;
    
    readerFrame = self.view.frame;
    viewFinderSize = CGSizeMake(readerFrame.size.width - 80, readerFrame.size.width - 80);

    
    if ([self isCkeckAVdevice])
    {
        [self initAVCaptureSession];
        
        [self initButtonView];
        
        [self initAVBorderView];
        
        [self initFourEdgeView];
        
        [self initHintView];
    }
    
    self.view.backgroundColor = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.2];
}

- (BOOL)isCkeckAVdevice
{
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    NSError *error = nil;
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
    if (error)
    {
        NSLog(@"没有摄像头%@", error.localizedDescription);
        input = nil;
       
        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"" message:@"没有摄像头"  delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil];
        [alertView show];
        
        return NO;
    }
    
    return  YES;
}

- (void)initAVCaptureSession
{
    //获取摄像设备
    AVCaptureDevice * device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    //创建输入流
    AVCaptureDeviceInput * input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
    //创建输出流
    AVCaptureMetadataOutput * output = [[AVCaptureMetadataOutput alloc]init];
    //设置代理 在主线程里刷新
    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    
    //初始化链接对象
    session = [[AVCaptureSession alloc]init];
    //高质量采集率
    [session setSessionPreset:AVCaptureSessionPresetHigh];
    
    [session addInput:input];
    [session addOutput:output];
    //设置扫码支持的编码格式(如下设置条形码和二维码兼容)
    output.metadataObjectTypes=@[AVMetadataObjectTypeQRCode,AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeCode128Code];
    
    AVCaptureVideoPreviewLayer * layer = [AVCaptureVideoPreviewLayer layerWithSession:session];
    layer.videoGravity=AVLayerVideoGravityResizeAspectFill;
    layer.frame=self.view.layer.bounds;
    [self.view.layer insertSublayer:layer atIndex:0];
    //开始捕获
    [session startRunning];

}

#pragma mark - init UI View

- (void)initScanLineView
{
    self.scanLineImageView =
    [[UIImageView alloc] initWithFrame:CGRectMake((readerFrame.size.width - 230)/2,
                                                  (readerFrame.size.height - viewFinderSize.height)/2,
                                                  230, 10)];
    self.scanLineImageView.image = [UIImage imageNamed:@"qr_scan_line"];
    
    [self.view addSubview:self.scanLineImageView];


}

- (void)initHintView
{
    _infoLabel =
    [[UILabel alloc] initWithFrame:CGRectMake((readerFrame.size.width - viewFinderSize.width)/2,
                                              (readerFrame.size.height + viewFinderSize.height)/2 + 20,
                                              viewFinderSize.width, 30)];
    _infoLabel.text = @"将二维码放入取景框中即可自动扫描";
    _infoLabel.font = [UIFont systemFontOfSize:13.0];
    _infoLabel.layer.cornerRadius = _infoLabel.frame.size.height / 2;
    _infoLabel.layer.backgroundColor = [[UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.5] CGColor];
    _infoLabel.textColor = [UIColor whiteColor];
    _infoLabel.textAlignment = NSTextAlignmentCenter;
    
    [self.view addSubview:_infoLabel];
}

- (void)initAVBorderView
{
    
    /* 画一个取景框结束 */
    
    UIView *topLine =
    [[UIView alloc] initWithFrame:CGRectMake((readerFrame.size.width - viewFinderSize.width)/2-1,
                                             (readerFrame.size.height - viewFinderSize.height)/2-1,
                                             viewFinderSize.width+2, 1)];
    topLine.backgroundColor = [UIColor grayColor];
    [self.view addSubview:topLine];
    
    UIView *bottomLine =
    [[UIView alloc] initWithFrame:CGRectMake((readerFrame.size.width - viewFinderSize.width)/2-1,
                                             (readerFrame.size.height + viewFinderSize.height)/2,
                                             viewFinderSize.width+2, 1)];
    bottomLine.backgroundColor = [UIColor grayColor];
    [self.view addSubview:bottomLine];
    
    UIView *leftLine =
    [[UIView alloc] initWithFrame:CGRectMake((readerFrame.size.width - viewFinderSize.width)/2-1,
                                             (readerFrame.size.height - viewFinderSize.height)/2-1,
                                             1, viewFinderSize.height+2)];
    leftLine.backgroundColor = [UIColor grayColor];
    [self.view addSubview:leftLine];
    
    UIView *rightLine =
    [[UIView alloc] initWithFrame:CGRectMake((readerFrame.size.width + viewFinderSize.width)/2,
                                             (readerFrame.size.height - viewFinderSize.height)/2-1,
                                             1, viewFinderSize.height+2)];
    rightLine.backgroundColor = [UIColor grayColor];
    [self.view addSubview:rightLine];
    
}

- (void)initFourEdgeView
{
    /* 画一个取景框开始 */
    // 正方形取景框的边长
    CGFloat edgeLength = 20.0;
    
    UIImageView *topLeft =
    [[UIImageView alloc] initWithFrame:CGRectMake((readerFrame.size.width - viewFinderSize.width)/2,
                                                  (readerFrame.size.height - viewFinderSize.height)/2,
                                                  edgeLength, edgeLength)];
    topLeft.image = [UIImage imageNamed:@"qr_top_left.png"];
    [self.view addSubview:topLeft];
    
    UIImageView *topRight =
    [[UIImageView alloc] initWithFrame:CGRectMake((readerFrame.size.width + viewFinderSize.width)/2 - edgeLength,
                                                  (readerFrame.size.height - viewFinderSize.height)/2,
                                                  edgeLength, edgeLength)];
    topRight.image = [UIImage imageNamed:@"qr_top_right.png"];
    [self.view addSubview:topRight];
    
    UIImageView *bottomLeft =
    [[UIImageView alloc] initWithFrame:CGRectMake((readerFrame.size.width - viewFinderSize.width)/2,
                                                  (readerFrame.size.height + viewFinderSize.height)/2 - edgeLength,
                                                  edgeLength, edgeLength)];
    bottomLeft.image = [UIImage imageNamed:@"qr_bottom_left"];
    [self.view addSubview:bottomLeft];
    
    UIImageView *bottomRight =
    [[UIImageView alloc] initWithFrame:CGRectMake((readerFrame.size.width + viewFinderSize.width)/2 - edgeLength,
                                                  (readerFrame.size.height + viewFinderSize.height)/2 - edgeLength,
                                                  edgeLength, edgeLength)];
    bottomRight.image = [UIImage imageNamed:@"qr_bottom_right"];
    [self.view addSubview:bottomRight];
    
    UIView *topLine =
    [[UIView alloc] initWithFrame:CGRectMake((readerFrame.size.width - viewFinderSize.width)/2-1,
                                             (readerFrame.size.height - viewFinderSize.height)/2-1,
                                             viewFinderSize.width+2, 1)];
    topLine.backgroundColor = [UIColor grayColor];
    [self.view addSubview:topLine];
    
    UIView *bottomLine =
    [[UIView alloc] initWithFrame:CGRectMake((readerFrame.size.width - viewFinderSize.width)/2-1,
                                             (readerFrame.size.height + viewFinderSize.height)/2,
                                             viewFinderSize.width+2, 1)];
    bottomLine.backgroundColor = [UIColor grayColor];
    [self.view addSubview:bottomLine];
    
    UIView *leftLine =
    [[UIView alloc] initWithFrame:CGRectMake((readerFrame.size.width - viewFinderSize.width)/2-1,
                                             (readerFrame.size.height - viewFinderSize.height)/2-1,
                                             1, viewFinderSize.height+2)];
    leftLine.backgroundColor = [UIColor grayColor];
    [self.view addSubview:leftLine];
    
    UIView *rightLine =
    [[UIView alloc] initWithFrame:CGRectMake((readerFrame.size.width + viewFinderSize.width)/2,
                                             (readerFrame.size.height - viewFinderSize.height)/2-1,
                                             1, viewFinderSize.height+2)];
    rightLine.backgroundColor = [UIColor grayColor];
    [self.view addSubview:rightLine];
}

- (void)initButtonView
{
    // 返回键
    UIButton *goBackButton =
    ({
        UIButton *button =
        [[UIButton alloc] initWithFrame:CGRectMake(20, 30, 36, 36)];
        [button setImage:[UIImage imageNamed:@"qr_vc_left"] forState:UIControlStateNormal];
        button.layer.cornerRadius = 18.0;
        button.layer.backgroundColor = [[UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.5] CGColor];
        [button addTarget:self action:@selector(goBack:) forControlEvents:UIControlEventTouchDown];
        button;
    });
    [self.view addSubview:goBackButton];
    
    // 控制散光灯
    UIButton *torchSwitch =
    ({
        UIButton *button =
        [[UIButton alloc] initWithFrame:CGRectMake(mainBounds.size.width-44-20, 30, 36, 36)];
        [button setImage:[UIImage imageNamed:@"qr_vc_right"] forState:UIControlStateNormal];
        button.layer.cornerRadius = 18.0;
        button.layer.backgroundColor = [[UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.5] CGColor];
        [button addTarget:self action:@selector(torchSwitch:) forControlEvents:UIControlEventTouchDown];
        button;
    });
    [self.view addSubview:torchSwitch];

}


- (void)createTimer
{
    self.scanLineTimer =
    [NSTimer scheduledTimerWithTimeInterval:LINE_SCAN_TIME
                                     target:self
                                   selector:@selector(moveUpAndDownLine)
                                   userInfo:nil
                                    repeats:YES];
}

// 扫描条上下滚动
- (void)moveUpAndDownLine
{
    CGRect scanLineframe = self.scanLineImageView.frame;
    scanLineframe.origin.y =
    (readerFrame.size.height - viewFinderSize.height)/2;
    self.scanLineImageView.frame = scanLineframe;
    self.scanLineImageView.hidden = NO;
    
    __weak __typeof(self) weakSelf = self;
    
    [UIView animateWithDuration:LINE_SCAN_TIME - 0.05
                     animations:^{
                         CGRect scanLineframe = weakSelf.scanLineImageView.frame;
                         scanLineframe.origin.y =
                         (readerFrame.size.height + viewFinderSize.height)/2 -
                         weakSelf.scanLineImageView.frame.size.height;
                         
                         weakSelf.scanLineImageView.frame = scanLineframe;
                     }
                     completion:^(BOOL finished) {
                         weakSelf.scanLineImageView.hidden = YES;
                     }];
}

#pragma mark - clicked method
// 返回
- (void)goBack:(id)sender
{
    [self.navigationController popViewControllerAnimated:YES];
}

// 控制散光灯
- (void)torchSwitch:(id)sender
{
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    NSError *error;
    if (device.hasTorch)
    {  // 判断设备是否有散光灯
        BOOL b = [device lockForConfiguration:&error];
        if (!b)
        {
            if (error)
            {
                NSLog(@"lock torch configuration error:%@", error.localizedDescription);
            }
            return;
        }
        device.torchMode =
        (device.torchMode == AVCaptureTorchModeOff ? AVCaptureTorchModeOn : AVCaptureTorchModeOff);
        [device unlockForConfiguration];
    }
}

#pragma mark - AVCaptureMetadataOutputObjectsDelegate

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects
      fromConnection:(AVCaptureConnection *)connection
{
    if (metadataObjects.count>0)
    {
        //[session stopRunning];
        AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjects objectAtIndex : 0 ];
        //输出扫描字符串
        NSLog(@"%@",metadataObject.stringValue);
        
       [[UIApplication sharedApplication] openURL:[NSURL URLWithString:metadataObject.stringValue]];
        
        //[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"https://itunes.apple.com/cn/app/quan-mink-ge/id910513149?mt=8"]];
    }
}

@end