ios实现二维码扫描

 1 #import "ViewController.h"
 2 #import <AVFoundation/AVFoundation.h>
 3 @interface ViewController ()<AVCaptureMetadataOutputObjectsDelegate>
 4 - (IBAction)scan:(UIButton *)sender;
 5 @property (strong,nonatomic)AVCaptureDevice *device;
 6 @property (strong,nonatomic)AVCaptureDeviceInput *input;
 7 @property (strong,nonatomic)AVCaptureMetadataOutput *output;
 8 @property (strong,nonatomic)AVCaptureSession *session;
 9 @property (strong,nonatomic)AVCaptureVideoPreviewLayer *preview;
10 @end
11 
12 @implementation ViewController
13 
14 - (void)viewDidLoad {
15     [super viewDidLoad];
16     // Do any additional setup after loading the view, typically from a nib.
17     
18 }
19 
20 - (void)setupCamera
21 {
22     // Device
23     _device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
24     
25     // Input
26     _input = [AVCaptureDeviceInput deviceInputWithDevice:self.device error:nil];
27     
28     // Output
29     _output = [[AVCaptureMetadataOutput alloc]init];
30     [_output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
31     
32     // Session
33     _session = [[AVCaptureSession alloc]init];
34     [_session setSessionPreset:AVCaptureSessionPresetHigh];
35     if ([_session canAddInput:self.input])
36     {
37         [_session addInput:self.input];
38     }
39     
40     if ([_session canAddOutput:self.output])
41     {
42         [_session addOutput:self.output];
43     }
44     
45     // 条码类型 AVMetadataObjectTypeQRCode
46     _output.metadataObjectTypes =@[AVMetadataObjectTypeQRCode];
47     
48     // Preview
49     _preview =[AVCaptureVideoPreviewLayer layerWithSession:self.session];
50     _preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
51     _preview.frame =CGRectMake(20,110,280,280);
52     [self.view.layer insertSublayer:self.preview atIndex:0];
53     
54     
55     
56     // Start
57     [_session startRunning];
58 }
59 #pragma mark AVCaptureMetadataOutputObjectsDelegate
60 - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
61 {
62     NSString *stringValue = [[NSString alloc] init];
63     
64     if (metadataObjects.count >0) {
65         AVMetadataMachineReadableCodeObject *metadataObject = [metadataObjects objectAtIndex:0];
66         stringValue = metadataObject.stringValue;
67     }
68     
69     [_session stopRunning];
70     NSLog(@"%@",stringValue);
71     [self dismissViewControllerAnimated:YES completion:^{
72         UIAlertView *alert = [[UIAlertView alloc]initWithTitle:nil
73                                                       message:stringValue
74                                                      delegate:nil
75                                             cancelButtonTitle:@"OK"
76                                             otherButtonTitles:nil,nil];
77         [alert show];
78     }];
79 }
80 - (IBAction)scan:(UIButton *)sender {
81     [self setupCamera];
82 }