使用系统提供的AVFoundation 实现二维码扫描（带动画）

注意这里的扫描必须真机测试

模拟器上是看不出来效果的

#import "ViewController.h"#import <AVFoundation/AVFoundation.h>@interface ViewController ()<AVCaptureMetadataOutputObjectsDelegate>//输入和输出设备的桥梁@property (nonatomic, strong) AVCaptureSession *session;/** *  <#Description#> */@property (nonatomic, weak) UIImageView *backgroundImageView;/** *  线 */@property (nonatomic, weak) UIImageView *scanLineImageView;@end@implementation ViewController- (UIImageView *)scanLineImageView{    if (!_scanLineImageView)    {        UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"qr_scan_line"]];        imageView.frame = CGRectMake(0, 0, self.backgroundImageView.frame.size.width, 1);        [self.backgroundImageView addSubview:imageView];                _scanLineImageView = imageView;    }        return _scanLineImageView;}- (UIImageView *)backgroundImageView{    if (!_backgroundImageView)    {        int space = 40;                UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"smk"]];        imageView.frame = CGRectMake(space, space, self.view.frame.size.width - 2 * space, self.view.frame.size.width - 2 * space);        [self.view addSubview:imageView];                _backgroundImageView = imageView;    }        return _backgroundImageView;}- (AVCaptureSession *)session{    if (!_session)    {        _session = [[AVCaptureSession alloc] init];    }        return _session;}- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.        /*     AVCaptureDevice 设备     AVCaptureDeviceInput 输入设备     AVCaptureMetadataOutput 输出设备     AVCaptureSession 输入和输出设备的桥梁，负责input和output数据交互。     */          }/** *  开始扫描 * *  @param sender <#sender description#> */- (IBAction)startScan:(id)sender{    if (!_session)    {        //1.设备        AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];                //2.输入设备        AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];                //3.输出设备        AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];        //设置代理        [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];        <pre name="code" class="objc">        output.metadataObjectTypes = @[AVMetadataObjectTypeQRCode,AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeCode128Code];

//4.输入和输出设备的桥梁，负责input和output数据交互 if ([self.session canAddInput:input]) { //添加输入设备 [self.session addInput:input]; } if ([self.session canAddOutput:output]) { //添加输出设备 [self.session addOutput:output]; } //可用类型 //[output availableMetadataObjectTypes]; //5. /* AVMetadataObjectTypeQRCode 二维码 */ //6.初始化要显示图像的layer //显示拍摄视频图像 AVCaptureVideoPreviewLayer *layer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.session]; layer.frame = self.view.bounds; layer.contentsGravity = kCAGravityResizeAspectFill; [self.view.layer insertSublayer:layer atIndex:0]; } //7.开始扫描 [self.session startRunning]; [self animationScan];}#pragma mark - 代理方法(可能会调用多次)- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{ //扫描成功 if (metadataObjects.count > 0) { //如果扫描成功就停止扫描 [self.session stopRunning]; //结果类 AVMetadataMachineReadableCodeObject *object = metadataObjects[0]; //获取扫描的数据 NSString *value = [object stringValue]; UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示" message:value delegate:nil cancelButtonTitle:@"Cancel" otherButtonTitles:nil, nil]; [alert show]; } }#pragma mark -/** * 扫描动画 */- (void)animationScan{ [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(updateScanLineFrame) userInfo:nil repeats:YES];}bool upMove;/** * 更新线的坐标 */- (void)updateScanLineFrame{ if (self.scanLineImageView.frame.origin.y <= 20) { //向下移动 upMove = NO; } else if(self.scanLineImageView.frame.origin.y >= self.backgroundImageView.frame.size.height - 20) { //向上移动 upMove = YES; } CGRect frame = self.scanLineImageView.frame; if (upMove) { frame.origin.y--; } else { frame.origin.y++; } //重新修改坐标 self.scanLineImageView.frame = frame; }- (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated.}@end