1、掃描二維碼可以，掃描條形碼一直沒有反應
2、demo只集成條形碼，則沒有這個問題
---
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Step1:需要導入：AVFoundation Framework 包含頭文件：
#import
Step2:設置捕獲會話
設置 AVCaptureSession 和 AVCaptureVideoPreviewLayer 成員
［即，創建會話和輸出對象］
Step3:創建會話，讀取輸入流
```Objective-C
- (void)beginScanning
{
//獲取攝像設備
AVCaptureDevice * device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
//創建輸入流
AVCaptureDeviceInput * input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
if (!input) return;
//創建輸出流
AVCaptureMetadataOutput * output = [[AVCaptureMetadataOutput alloc]init];
//設置代理 在主線程里刷新
[output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
//設置有效掃描區域
CGRect scanCrop=[self getScanCrop:_scanWindow.bounds readerViewBounds:self.view.frame];
output.rectOfInterest = scanCrop;
__weak typeof(self) weakSelf = self;
[[NSNotificationCenter defaultCenter]addObserverForName:AVCaptureInputPortFormatDescriptionDidChangeNotification?object:nil?queue:[NSOperationQueue mainQueue]?usingBlock:^(NSNotification * _Nonnull note) {
if (weakSelf){
//調整掃描區域
AVCaptureMetadataOutput *output = weakSelf.session.outputs.firstObject;
output.rectOfInterest = scanCrop;
}
}];
//初始化鏈接對象
_session = [[AVCaptureSession alloc]init];
//高質量采集率
[_session setSessionPreset:AVCaptureSessionPresetHigh];
[_session addInput:input];
[_session addOutput:output];
//設置掃碼支持的編碼格式(如下設置條形碼和二維碼兼容)
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];
//開始捕獲
[_session startRunning];
}
Step4:停止讀取
-(void)stopReading
{
// 停止會話
[_captureSessionstopRunning];
_captureSession=nil;
}
Step5:代理中獲取捕獲數據，并處理
-(void)captureOutput:(AVCaptureOutput*)captureOutputdidOutputMetadataObjects:(NSArray*)metadataObjectsfromConnection:(AVCaptureConnection*)connection
{
if(metadataObjects!=nil&&[metadataObjectscount]>0)
{
AVMetadataMachineReadableCodeObject* metadataObj =[metadataObjectsobjectAtIndex:0];
NSString*result;
if([[metadataObjtype]isEqualToString:AVMetadataObjectTypeQRCode])
{
result=metadataObj.stringValue;
}
else
{
NSLog(@"不是二維碼");
}[selfperformSelectorOnMainThread:@selector(reportScanResult:)withObject:resultwaitUntilDone:NO];
}
}
```
---
以上基本就是二維碼的獲取流程，和掃一掃二維碼伴隨的就是開啟系統照明，這個比較簡單，也是利用AVCaptureDevice,請看如下實現：
參考鏈接：
http://my.oschina.net/jeans/blog/519365
http://www.cnblogs.com/lzjsky/p/5057134.html
