iOS使用AVFoundation实现二维码扫描

1
2
3
4
5
6
7
8
9
10

#import <AVFoundation/AVFoundation.h> static const char *kScanQRCodeQueueName = "ScanQRCodeQueue"; @interface ViewController () <AVCaptureMetadataOutputObjectsDelegate>
.....
@property (nonatomic) AVCaptureSession *captureSession;
@property (nonatomic) AVCaptureVideoPreviewLayer *videoPreviewLayer;
@property (nonatomic) BOOL lastResult;
@end


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37

- (BOOL)startReading
{
// 获取 AVCaptureDevice 实例
NSError * error;
AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
// 初始化输入流
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];
if (!input) {
NSLog(@"%@", [error localizedDescription]);
return NO;
}
// 创建会话
_captureSession = [[AVCaptureSession alloc] init];
// 添加输入流
[_captureSession addInput:input];
// 初始化输出流
AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];
// 添加输出流
[_captureSession addOutput:captureMetadataOutput]; // 创建dispatch queue.
dispatch_queue_t dispatchQueue;
dispatchQueue = dispatch_queue_create(kScanQRCodeQueueName, NULL);
[captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];
// 设置元数据类型 AVMetadataObjectTypeQRCode
[captureMetadataOutput setMetadataObjectTypes:[NSArray arrayWithObject:AVMetadataObjectTypeQRCode]]; // 创建输出对象
_videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];
[_videoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
[_videoPreviewLayer setFrame:_sanFrameView.layer.bounds];
[_sanFrameView.layer addSublayer:_videoPreviewLayer];
// 开始会话
[_captureSession startRunning]; return YES;
}


1
2
3
4
5
6
7

- (void)stopReading
{
// 停止会话
[_captureSession stopRunning];
_captureSession = nil;
}


1
2
3
4
5
6
7
8
9
10
11
12
13
14

-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects
fromConnection:(AVCaptureConnection *)connection
{
if (metadataObjects != nil && [metadataObjects count] > 0) {
AVMetadataMachineReadableCodeObject *metadataObj = [metadataObjects objectAtIndex:0];
NSString *result;
if ([[metadataObj type] isEqualToString:AVMetadataObjectTypeQRCode]) {
result = metadataObj.stringValue;
} else {
NSLog(@"不是二维码");
}
[self performSelectorOnMainThread:@selector(reportScanResult:) withObject:result waitUntilDone:NO];
}
}


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

- (void)reportScanResult:(NSString *)result
{
[self stopReading];
if (!_lastResult) {
return;
}
_lastResut = NO;
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"二维码扫描"
message:result
delegate:nil
cancelButtonTitle:@"取消"
otherButtonTitles: nil];
[alert show];
// 以下处理了结果，继续下次扫描
_lastResult = YES;
}


1
2
3
4
5
6
7
8
9
10
11
12
13

- (void)systemLightSwitch:(BOOL)open
{
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if ([device hasTorch]) {
[device lockForConfiguration:nil];
if (open) {
[device setTorchMode:AVCaptureTorchModeOn];
} else {
[device setTorchMode:AVCaptureTorchModeOff];
}
[device unlockForConfiguration];
}
}


1
2
3
4
5
6
7
8
9
10
11
12
13

/*!
@method captureOutput:didOutputMetadataObjects:fromConnection:
.....
@discussion
Delegates receive this message whenever the output captures and emits new objects, as specified by
its metadataObjectTypes property. Delegates can use the provided objects in conjunction with other APIs
for further processing. This method will be called on the dispatch queue specified by the output‘s
metadataObjectsCallbackQueue property. **This method may be called frequently** so it must be efficient to
prevent capture performance problems, including dropped metadata objects. Clients that need to reference metadata objects outside of the scope of this method must retain them and
then release them when they are finished with them.
*/