ios7新增api实现扫描二维码

本来用的ZBar开源库实现的扫描二维码，可是貌似不支持arm64了，也没有在更新。

如今不用适配ios7下面。而iOS新增系统API已支持扫码，參考老外的一篇博客做了个demo。须要的能够參考下

參考博客：http://www.appcoda.com/qr-code-ios-programming-tutorial/

#import <AVFoundation/AVFoundation.h>
@interface QRCodeReadController : BaseViewController<AVCaptureMetadataOutputObjectsDelegate>

@property (weak, nonatomic) IBOutlet UIView *viewPreview;
@end

在xib上加一个viewPreview，用来扫码时动态显示获取到的摄像头的内容

@interface QRCodeReadController ()
{
    NSInteger maxY;
    NSInteger minY;
    NSTimer *timer;
    
    UIImageView *line;
}
@property (nonatomic) BOOL isReading;

@property (nonatomic, strong) AVCaptureSession *captureSession;
@property (nonatomic, strong) AVCaptureVideoPreviewLayer *videoPreviewLayer;

-(BOOL)startReading;
-(void)stopReading;

@end

@implementation QRCodeReadController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    _isReading = NO;
    if ([self startReading]) {
        maxY = 280;
        minY = 2;
        line =[[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 280, 10)];  // 0 -200
        [line setImage:[UIImage imageNamed:@"e0"]];
        [_viewPreview addSubview:line];
        
        timer = [NSTimer scheduledTimerWithTimeInterval:1.0/40 target:self selector:@selector(move) userInfo:nil repeats:YES];
    };
    

}

/*
 *
 *
 AVCaptureMetadataOutput object. This class in combination with the AVCaptureMetadataOutputObjectsDelegate protocol will manage to intercept any metadata found in the input device (meaning data in a QR code captured by our camera) and translate it to a human readable format.
 */
- (BOOL)startReading {
    NSError *error;
    
    AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];
    
    if (!input) {
        NSLog(@"%@", [error localizedDescription]);
        return NO;
    }
    _captureSession = [[AVCaptureSession alloc] init];
    [_captureSession addInput:input];
    
    AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];
    [_captureSession addOutput:captureMetadataOutput];
    
    
    dispatch_queue_t dispatchQueue;
    dispatchQueue = dispatch_queue_create("myQueue", NULL);
    [captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];
    [captureMetadataOutput setMetadataObjectTypes:[NSArray arrayWithObject:AVMetadataObjectTypeQRCode]];
    
    
    //show to user what the camera of the device sees  using a AVCaptureVideoPreviewLayer
    _videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];
    [_videoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
    [_videoPreviewLayer setFrame:_viewPreview.layer.bounds];
    [_viewPreview.layer addSublayer:_videoPreviewLayer];
    
    [_captureSession startRunning];

    return YES;
}

-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{
    if (metadataObjects != nil && [metadataObjects count] > 0) {
        AVMetadataMachineReadableCodeObject *metadataObj = [metadataObjects objectAtIndex:0];
        if ([[metadataObj type] isEqualToString:AVMetadataObjectTypeQRCode]) {
            [self performSelectorOnMainThread:@selector(stopReading) withObject:nil waitUntilDone:NO];
            NSLog(@"metadataObj  string = %@",[metadataObj stringValue]);
            _isReading = NO;
        }
    }
}

-(void)stopReading{
    [_captureSession stopRunning];
    _captureSession = nil;
    
    [_videoPreviewLayer removeFromSuperlayer];
}


// 扫描时，移动扫描线
-(void)move
{
    NSLog(@"+++");
    static BOOL flag = TRUE;  // true down  and false up
    if (flag) {
        if (line.frame.origin.y <maxY) {
            line.frame = CGRectMake(
                                    line.frame.origin.x, line.frame.origin.y +5,
                                    line.frame.size.width, line.frame.size.height
                                    );
        }else{
            flag = !flag;
            if (_isReading&&[timer isValid]) {
                [timer invalidate];
            }
        }
    }else
    {
        if (line.frame.origin.y >minY) {
            line.frame = CGRectMake(
                                    line.frame.origin.x, line.frame.origin.y -5,
                                    line.frame.size.width, line.frame.size.height
                                    );
        }else
        {
            flag = !flag;
        }
    }
    
    
}

/*****************************************************************************************/

识别图片二维码

如今有从含二维码的图片直接出二维码中信息的需求，查相关资料发现。原生api在iOS8才支持（CIQRCodeFeature
）

见 http://stackoverflow.com/questions/27505420/is-it-possible-to-decode-qrcode-image-to-value

解决方式用的zxing的ZXQRcodeDecoder

http://stackoverflow.com/questions/15575554/zxingobjc-cant-decode-image-taken-from-uiimagepickercontroller

    NSString *path = [[NSBundle mainBundle] pathForResource:@"code" ofType:@"png"];
    UIImage *image = [UIImage imageWithContentsOfFile:path];
    
    NSError *error = nil;

    
    ZXQRCodeReader *reader = [[ZXQRCodeReader alloc]init];
    
    ZXLuminanceSource *source = [[ZXCGImageLuminanceSource alloc] initWithCGImage:[image CGImage]];
    ZXHybridBinarizer *binazer = [ZXHybridBinarizer binarizerWithSource:source];
    ZXBinaryBitmap *bitmap = [[ZXBinaryBitmap alloc]initWithBinarizer:binazer];
    
    ZXResult *result = [reader decode:bitmap
                                hints:nil
                                error:&error];
    if(result){
        NSLog(@"%@",result);
        [[[UIAlertView alloc] initWithTitle:@"Success" message:result.text
                                   delegate:nil
                          cancelButtonTitle:@"OK"
                          otherButtonTitles:nil, nil] show];
    } else {
        // Use error to determine why we didn't get a result, such as a barcode
        // not being found, an invalid checksum, or a format inconsistency.
        [[[UIAlertView alloc] initWithTitle:@"ERROR" message:[error localizedDescription]
                                   delegate:nil
                          cancelButtonTitle:@"OK"
                          otherButtonTitles:nil, nil] show];
    }