如何简单快速的创建二维码扫描UI界面

qrScan.gif

我们接下来将用maskLayer的方法，用最少的代码去绘制一个完整的二维码扫描UI界面

UIView *maskView = [[UIView alloc] initWithFrame:self.view.bounds];
maskView.backgroundColor = [UIColor colorWithRed:100/255.0 green:100/255.0 blue:100/255.0 alpha:0.4];
[self.view addSubview:maskView];

//创建mask layer
CAShapeLayer *maskLayer = [CAShapeLayer layer];
    
CGMutablePathRef path = CGPathCreateMutable();
    
CGFloat pathWidth = Width-100;
CGFloat orginY = (Height-pathWidth)/2-50;
//内部方框path
CGPathAddRect(path, nil, CGRectMake(50, orginY, pathWidth, pathWidth));
//外部大框path
CGPathAddRect(path, nil, maskView.bounds);
//两个path取差集，即去除差集部分
maskLayer.fillRule = kCAFillRuleEvenOdd;
maskLayer.path = path;
maskView.layer.mask = maskLayer;

这样我们便创建出我们需要的中部镂空，旁边灰色半透明的UI界面

bg 效果图

添加环境光感应功能

在光线暗的时候提示打开手电筒

#import <AVFoundation/AVFoundation.h>
#import <ImageIO/ImageIO.h>

- (void)initScan {
    //获取摄像设备
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    
    //创建输入流
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
    //创建输出流
    AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
    //设置扫描有效区域
    output.rectOfInterest = CGRectMake(0.1, 0.2, 0.5, 0.5);
    //设置代理 在主线程里刷新
    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    
    //设置光感代理输出
    AVCaptureVideoDataOutput *respondOutput = [[AVCaptureVideoDataOutput alloc] init];
    [respondOutput setSampleBufferDelegate:self queue:dispatch_get_main_queue()];
    
    //初始化链接对象
    _session = [[AVCaptureSession alloc] init];
    //高质量采集率
    [_session setSessionPreset:AVCaptureSessionPresetHigh];
    
    if ([_session canAddInput:input]) [_session addInput:input];
    if ([_session canAddOutput:output]) [_session addOutput:output];
    if ([_session canAddOutput:respondOutput]) [_session addOutput:respondOutput];
    
    //设置扫码支持的编码格式
    output.metadataObjectTypes = @[AVMetadataObjectTypeQRCode, AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeCode128Code];
    
    _layer = [AVCaptureVideoPreviewLayer layerWithSession:_session];
    _layer.videoGravity = AVLayerVideoGravityResizeAspectFill;
    _layer.frame = self.view.frame;
    [self.view.layer insertSublayer:_layer atIndex:0];
    //开始捕获
    [_session startRunning];
}

#pragma mark - 光感回调
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {
    CFDictionaryRef metadataDict = CMCopyDictionaryOfAttachments(NULL,sampleBuffer, kCMAttachmentMode_ShouldPropagate);
    NSDictionary *metadata = [[NSMutableDictionary alloc] initWithDictionary:(__bridge NSDictionary*)metadataDict];
    CFRelease(metadataDict);
    NSDictionary *exifMetadata = [[metadata objectForKey:(NSString *)kCGImagePropertyExifDictionary] mutableCopy];
    // 该值在 -5~12 之间，值越大光线越强
    float brightnessValue = [[exifMetadata objectForKey:(NSString *)kCGImagePropertyExifBrightnessValue] floatValue];
    NSLog(@"%f", brightnessValue);
}

scan.gif

接下来添加功能的UI界面就不做赘述，如有需要，Demo点这里