二維碼掃描（iOS原生二維碼掃描）

1、關於二維碼掃描的第三方庫有不少：例如比較經常使用的兩個

 1.ZBar SDK ZBar爲咱們提供了兩種使用方式，一種是直接調用ZBar提供的ZBarReaderViewController打開一個掃描界面，另外一種方式是使用ZBar提供的能夠嵌在其餘視圖中的ZBarReaderView，實際項目中咱們更可能會使用第二種方式，這可讓咱們對界面作更多的定製,詳細的百度查找相關文檔來看。

 

 2.ZXing(Github鏡像地址)是一個開源的條碼生成和掃描庫（開源協議爲Apache2.0)。它不但支持衆多的條碼格式，並且有各類語言的實現版本，它支持的語言包括：Java、 C++、 C#、 Objective-C、ActionScript以及Ruby;首先去Google Code或Github將ZXing的代碼下載下來，整個工程比較大，咱們只須要其中涉及iOS的部分，因此最好作一些裁剪。簡單來講，咱們只須要保留cpp和iphone這2個文件夾，其他的所有刪掉。

2、

1.本次介紹的是：iOS原生二維碼掃描，利用iOS7自帶的AVFoundation Framework 來實現二維碼掃描

 關於AVFoundation：AVFoundation是一個很大基礎庫，用來建立基於時間的視聽媒體，可使用它來檢查、建立、編輯或媒體文件，也能夠輸入流從設備和操做視頻實時捕捉和回放。詳細框架介紹見官網：About AV Foundation，本文只是介紹若是使用AVFoundation獲取二維碼。

 

 2.首先獲取流媒體信息咱們須要AVCaptureSession對象來管理輸入流和輸出流，AVCaptureVideoPreviewLayer對象來顯示信息。

 

1>AVCaptureSession 管理輸入(AVCaptureInput)和輸出(AVCaptureOutput)流，包含開啓和中止會話方法。

2>AVCaptureDeviceInput 是AVCaptureInput的子類,能夠做爲輸入捕獲會話，用AVCaptureDevice實例初始化。

3>AVCaptureDevice 表明了物理捕獲設備如:攝像機。用於配置等底層硬件設置相機的自動對焦模式。

4>AVCaptureMetadataOutput 是AVCaptureOutput的子類，處理輸出捕獲會話。捕獲的對象傳遞給一個委託實現

5>AVCaptureMetadataOutputObjectsDelegate協議。協議方法在指定的派發隊列（dispatch queue）上執行。

6>AVCaptureVideoPreviewLayerCALayer的一個子類，顯示捕獲到的相機輸出流。

  1 /*
  2  步驟以下：
  3  1.導入AVFoundation框架，引入<AVFoundation/AVFoundation.h>
  4  2.設置一個用於顯示掃描的view
  5  3.實例化AVCaptureSession、AVCaptureVideoPreviewLayer
  6  */
  7 
  8 #import "ViewController.h"
  9 #import <AVFoundation/AVFoundation.h>
 10 @interface ViewController ()<AVCaptureMetadataOutputObjectsDelegate>
 11 
 12 @property (strong,nonatomic) UIView *viewPreview ;
 13 @property (strong,nonatomic) UILabel *lblStatus ;
 14 @property (strong,nonatomic) UIButton *startBtn ;
 15 
 16 @property (strong,nonatomic) UIView *boxView ;
 17 @property (nonatomic) BOOL isReading ;
 18 @property (strong,nonatomic) CALayer *scanLayer;
 19 
 20 -(BOOL)startReading;
 21 -(void)stopReading ;
 22 
 23 //捕捉會話
 24 @property (strong,nonatomic) AVCaptureSession *captureSession;
 25 //展現layer
 26 @property (strong,nonatomic) AVCaptureVideoPreviewLayer *videoPreviewLayer;
 27 
 28 @end
 29 
 30 
 31 @implementation ViewController
 32 
 33 - (void)viewDidLoad {
 34     [super viewDidLoad];
 35 //    self.view.backgroundColor = [UIColor whiteColor];
 36     self.captureSession = nil ;
 37     _isReading = NO ;
 38     [self initUI];
 39     
 40     
 41 }
 42 
 43 -(BOOL)startReading
 44 {
 45     NSError *error;
 46     //1.初始化捕捉設備(AVCaptureDevice),類型爲AVMediaTypeVideo
 47     AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
 48     //2.用captureDevice建立輸入流
 49     AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];
 50     if (!input) {
 51         NSLog(@"%@",[error localizedDescription]);
 52         return NO ;
 53     }
 54     //3.建立媒體數據輸出流
 55     AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];
 56 //    AVCaptureOutput *outPut = [[AVCaptureOutput alloc] init];
 57     //4.實例化捕捉會話
 58     _captureSession = [[AVCaptureSession alloc] init];
 59     //4.1將輸入流添加帶會話
 60     [_captureSession addInput:input];
 61     //4.2將媒體輸出流添加帶會話中
 62     [_captureSession addOutput:captureMetadataOutput];
 63     //5.建立串行隊列，並加媒體輸出流添加到隊列當中
 64     dispatch_queue_t dispatchQueue;
 65     dispatchQueue = dispatch_queue_create("myQueue", NULL);
 66     //5.1.設置代理
 67 //    [captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];
 68     //
 69     //設置代理 刷新線程
 70     [captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
 71     //5.2.設置輸出媒體數據類型爲QRCode
 72 //    [captureMetadataOutput setMetadataObjectTypes:[NSArray arrayWithObject:AVMetadataObjectTypeQRCode]];
 73     if (captureMetadataOutput) {
 74         
 75         //設置掃碼支持的編碼格式
 76         NSMutableArray *array = [[NSMutableArray alloc] initWithCapacity:0];
 77         
 78         if ([captureMetadataOutput.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeQRCode]) {
 79             [array addObject:AVMetadataObjectTypeQRCode];
 80         }
 81         if ([captureMetadataOutput.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeEAN13Code]) {
 82             [array addObject:AVMetadataObjectTypeEAN13Code];
 83         }
 84         if ([captureMetadataOutput.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeEAN8Code]) {
 85             [array addObject:AVMetadataObjectTypeEAN8Code];
 86         }
 87         if ([captureMetadataOutput.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeCode128Code]) {
 88             [array addObject:AVMetadataObjectTypeCode128Code];
 89         }
 90         captureMetadataOutput.metadataObjectTypes = array;
 91     }
 92     
 93     //6.實例化預覽圖層
 94     _videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSessionWithNoConnection:_captureSession];
 95     //7.設置預覽圖層填充方式
 96     [_videoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
 97     //8.設置圖層的frame
 98     [_videoPreviewLayer setFrame:_viewPreview.layer.bounds];
 99     //9.將圖層添加到預覽view的圖層上
100     [_viewPreview.layer addSublayer:_videoPreviewLayer];
101     //10.設置掃描範圍
102     captureMetadataOutput.rectOfInterest = CGRectMake(0.2f, 0.2f, 0.8f, 0.8f);
103     //10.1掃描框
104     CGFloat width = _viewPreview.bounds.size.width ;
105     CGFloat height = _viewPreview.bounds.size.height;
106     self.boxView = [[UIView alloc] initWithFrame:CGRectMake(width * 0.2f, height * 0.2f, width - width * 0.4f, height - height * 0.4f)];
107     _boxView.layer.borderColor = [[UIColor greenColor] CGColor];
108     _boxView.layer.borderWidth = 1.0f ;
109     [_viewPreview addSubview:_boxView];
110     //10.2掃描線
111     self.scanLayer = [[CALayer alloc] init];
112     _scanLayer.frame = CGRectMake(0, 0, _boxView.bounds.size.width, 1);
113     _scanLayer.backgroundColor = [[UIColor brownColor] CGColor];
114     [_boxView.layer insertSublayer:_scanLayer atIndex:0];
115     NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:0.2f target:self selector:@selector(moveScanLayer:) userInfo:nil repeats:YES];
116     [timer fire];
117     //10.開始掃描
118     [_captureSession startRunning];
119     return YES ;
120 }
121 
122 
123 -(void)stopReading{
124     [_captureSession stopRunning];
125     _captureSession = nil;
126     [_scanLayer removeFromSuperlayer];
127     [_videoPreviewLayer removeFromSuperlayer];
128 }
129 
130 #pragma mark --實現計時器方法moveScanLayer:(NSTimer *)timer
131 
132 - (void)moveScanLayer:(NSTimer *)timer
133 {
134     CGRect frame = _scanLayer.frame;
135     if (_boxView.frame.size.height < _scanLayer.frame.origin.y) {
136         frame.origin.y = 0;
137         _scanLayer.frame = frame;
138     }else{
139         frame.origin.y += 5;
140         [UIView animateWithDuration:0.1 animations:^{
141             _scanLayer.frame = frame;
142         }];
143     }
144 }
145 
146 #pragma mark --初始化控件
147 -(void)initUI
148 {
149     self.viewPreview = [[UIView alloc] init];
150     self.viewPreview.frame = CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height -200);
151 //    self.viewPreview.backgroundColor = [UIColor clearColor];
152 //    self.viewPreview.alpha = 0.1f ;
153     [self.view addSubview:_viewPreview];
154     
155     self.startBtn = [UIButton buttonWithType:UIButtonTypeSystem];
156     _startBtn.frame = CGRectMake(100, self.view.bounds.size.height - 100, 175, 30);
157     [_startBtn setTitle:@"開始" forState:UIControlStateNormal];
158     [_startBtn addTarget:self action:@selector(startStopReading:) forControlEvents:UIControlEventTouchUpInside];
159     [self.view addSubview:_startBtn];
160 }
161 
162 #pragma mark --實現開始和中止方法
163 -(void)startStopReading:(UIButton *)btn
164 {
165     if (!_isReading) {
166         
167         if ([self startReading]) {
168             [_startBtn setTitle:@"中止" forState:UIControlStateNormal];
169         }
170     }
171     else
172     {
173             [self stopReading];
174             [_startBtn setTitle:@"開始" forState:UIControlStateNormal];
175     }
176     
177     _isReading = !_isReading ;
178 }
179 
180 - (void)didReceiveMemoryWarning {
181     [super didReceiveMemoryWarning];
182     // Dispose of any resources that can be recreated.
183 }
184 
185 
186 #pragma mark --實現AVCaptureMetadataOutputObjectsDelegate協議方法
187 -(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
188 {
189     if (metadataObjects.count > 0) {
190         AVMetadataMachineReadableCodeObject *metadataObject = [metadataObjects firstObject];
191          NSLog(@"................%@",metadataObject.stringValue);
192         [self performSelectorOnMainThread:@selector(stopReading) withObject:nil waitUntilDone:NO];
193 
194     }
195 }
196 
197 
198 - (BOOL)shouldAutorotate
199 {
200     return NO;
201 }
202 @end