iOS 二维码 学习

这段时间忙着交接工作,找工作,找房子,入职,杂七杂八的,差不多一个月没有静下来学习了.这周末晚上等外卖的时间学习一下二维码的制作与扫描.

项目采用OC语言,只要使用iOS自带的CoreImage框架,通过滤镜CIFilter生成二维码,扫描使用原生自带相机实现.

开撸:

先写一个类,封装把string转换我image和把CIImage转换为string:

QRImage.h

 //
 //  QRImage.h
 //  QRcode
 //
 //  Created by Shaoting Zhou on 2017/11/19.
 //  Copyright © 2017年 Shaoting Zhou. All rights reserved.
 //

 #import <Foundation/Foundation.h>
 #import <CoreImage/CoreImage.h>
 #import <UIKit/UIKit.h>

 @interface QRImage : NSObject

 + (UIImage *)imageWithQRString:(NSString *)string;  //把string转换我image
 + (NSString *)stringFromCiImage:(CIImage *)ciimage; //把CIImage转换为string

 @end

QRImage.m

 //
 //  QRImage.m
 //  QRcode
 //
 //  Created by Shaoting Zhou on 2017/11/19.
 //  Copyright © 2017年 Shaoting Zhou. All rights reserved.
 //

 #import "QRImage.h"

 @implementation QRImage

 #pragma mark - 把string转换为Image
 + (UIImage *)imageWithQRString:(NSString *)string{
     NSData * stringData = [string dataUsingEncoding:NSUTF8StringEncoding];

     CIFilter * qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"]; //过滤器
     [qrFilter setValue:stringData forKey:@"inputMessage"];
     [qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];  //纠错等级
     UIImage * image =  [self createUIImageFromCIImage:qrFilter.outputImage withSize:];
     return image;
 }

 #pragma mark - CIImgae ->  UIImage
 + (UIImage *)createUIImageFromCIImage:(CIImage *)image withSize:(CGFloat)size{
     CGRect extent = CGRectIntegral(image.extent);
     CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));

     //1.创建bitmap;
     size_t width = CGRectGetWidth(extent) * scale;
     size_t height = CGRectGetHeight(extent) * scale;
     CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
     CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, , , cs, (CGBitmapInfo)kCGImageAlphaNone);
     CIContext *context = [CIContext contextWithOptions:nil];
     CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
     CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
     CGContextScaleCTM(bitmapRef, scale, scale);
     CGContextDrawImage(bitmapRef, extent, bitmapImage);

     //2.保存bitmap到图片
     CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
     CGContextRelease(bitmapRef);
     CGImageRelease(bitmapImage);
     return [UIImage imageWithCGImage:scaledImage];

 }

 #pragma mark - 把image转换为string
 + (NSString *)stringFromCiImage:(CIImage *)ciimage{
     NSString * content = nil;
     if(!ciimage){
         return  content;
     }
     CIDetector * detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:[CIContext contextWithOptions:nil] options:@{CIDetectorAccuracy:CIDetectorAccuracyHigh}];
     NSArray * features = [detector featuresInImage:ciimage];
     if(features.count){
         for (CIFeature * feature in features) {
             if([feature isKindOfClass:[CIQRCodeFeature class]]){
                 content = ((CIQRCodeFeature *)feature).messageString;
                 break;
             }
         }
     }else{
         NSLog(@"解析失败,确保硬件支持");
     }

     return content;
 }
 @end

上面的代码就是关键之处.

下面,写一个界面生成二维码,通过上面写好的string转换我image,显示在屏幕之上.

MainViewController.h

 //
 //  MainViewController.h
 //  QRcode
 //
 //  Created by Shaoting Zhou on 2017/11/18.
 //  Copyright © 2017年 Shaoting Zhou. All rights reserved.
 //

 #import <UIKit/UIKit.h>
 #import "QRImage.h"
 #import "ScanViewController.h"

 @interface MainViewController : UIViewController
 @property (nonatomic,strong) UIImageView * qrImageView;
 @property (nonatomic,strong) UITextField * textField;
 @end

MainViewController.m

 //
 //  MainViewController.m
 //  QRcode
 //
 //  Created by Shaoting Zhou on 2017/11/18.
 //  Copyright © 2017年 Shaoting Zhou. All rights reserved.
 //

 #import "MainViewController.h"

 @interface MainViewController ()

 @end

 @implementation MainViewController

 - (void)viewDidLoad {
     [super viewDidLoad];
     [self setUI];
     self.title = @"生成二维码";

     self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"扫描" style:(UIBarButtonItemStylePlain) target:self action:@selector(scangQRimage)];
 }

 -(void)setUI{
     self.textField = [[UITextField alloc]initWithFrame:CGRectMake(, , , )];
     self.textField.borderStyle = UITextBorderStyleRoundedRect;
     [self.view addSubview:self.textField];

     UIButton * btn = [[UIButton alloc]initWithFrame:CGRectMake(, , , )];
     [btn setTitle:@"生成二维码" forState:(UIControlStateNormal)];
     [btn setTitleColor:[UIColor redColor] forState:(UIControlStateNormal)];
     [btn addTarget:self action:@selector(makeQRcode) forControlEvents:(UIControlEventTouchUpInside)];
     [self.view addSubview:btn];

     self.qrImageView = [[UIImageView alloc]initWithFrame:CGRectMake(, , , )];
     [self.view addSubview:self.qrImageView];

 }
 #pragma mark - 生成二维码
 -(void)makeQRcode{
     [self.textField resignFirstResponder];
     UIImage * img = [QRImage imageWithQRString:self.textField.text];
     self.qrImageView.image = img;
 }

 #pragma mark - push到扫描界面
 -(void)scangQRimage{
     ScanViewController * scanVC = [[ScanViewController alloc]init];
     [self.navigationController pushViewController:scanVC animated:NO];
 }

 - (void)didReceiveMemoryWarning {
     [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
 }

 /*
 #pragma mark - Navigation

 // In a storyboard-based application, you will often want to do a little preparation before navigation
 - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
     // Get the new view controller using [segue destinationViewController].
     // Pass the selected object to the new view controller.
 }
 */

 @end

再写一个界面扫描二维码和通过相册选择二维码扫描,通过上面写好的把CIImage转换为string,扫描出二维码信息显示出来即可.

ScanViewController.h

 //
 //  ScanViewController.h
 //  QRcode
 //
 //  Created by Shaoting Zhou on 2017/11/19.
 //  Copyright © 2017年 Shaoting Zhou. All rights reserved.
 //

 #import <UIKit/UIKit.h>
 #import <AVFoundation/AVFoundation.h>
 #import "QRImage.h"
 @interface ScanViewController : UIViewController <AVCaptureMetadataOutputObjectsDelegate,UINavigationControllerDelegate,UIImagePickerControllerDelegate>
 @property (nonatomic,strong) AVCaptureSession * session;
 @property (nonatomic,strong) UITextField * textField;

 @end

ScanViewController.m

 //
 //  ScanViewController.m
 //  QRcode
 //
 //  Created by Shaoting Zhou on 2017/11/19.
 //  Copyright © 2017年 Shaoting Zhou. All rights reserved.
 //

 #import "ScanViewController.h"

 @interface ScanViewController ()

 @end

 @implementation ScanViewController

 - (void)viewDidLoad {
     [super viewDidLoad];
     self.title = @"扫描二维码";

     self.textField = [[UITextField alloc]initWithFrame:CGRectMake(, , , )];
     self.textField.borderStyle = UITextBorderStyleRoundedRect;
     self.textField.userInteractionEnabled = NO;
     [self.view addSubview:self.textField];

     self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"相册" style:(UIBarButtonItemStylePlain) target:self action:@selector(presentImagePicker)];

 }
 - (void)viewWillAppear:(BOOL)animated{
     [super viewWillAppear:animated];
     [self startScan];

 }

 #pragma  mark - 开始扫描
 - (void)startScan{
     if([AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo] == AVAuthorizationStatusAuthorized || [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo] == AVAuthorizationStatusNotDetermined ){
         self.session = [[AVCaptureSession alloc]init];
         AVCaptureDeviceInput * input = [[AVCaptureDeviceInput alloc]initWithDevice:[AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo] error:nil];
         if(input){
             [self.session addInput:input];
         }

         AVCaptureMetadataOutput * output = [[AVCaptureMetadataOutput alloc]init];
         [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
         if(output){
             [self.session addOutput:output];
         }

         NSMutableArray * ary = [[NSMutableArray alloc]init];
         if([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeQRCode]){
             [ary addObject:AVMetadataObjectTypeQRCode];
         }
         if([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeEAN13Code]){
             [ary addObject:AVMetadataObjectTypeEAN13Code];
         }
         if([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeEAN8Code]){
             [ary addObject:AVMetadataObjectTypeEAN8Code];
         }
         if([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeCode128Code]){
             [ary addObject:AVMetadataObjectTypeCode128Code];
         }
         output.metadataObjectTypes = ary;

         AVCaptureVideoPreviewLayer * layer = [AVCaptureVideoPreviewLayer layerWithSession:self.session];
         layer.videoGravity = AVLayerVideoGravityResizeAspectFill;
         layer.frame = CGRectMake((self.view.bounds.size.width - )/, , , );
         [self.view.layer addSublayer:layer];

         UIImageView * imageView = [[UIImageView alloc]initWithFrame:CGRectMake((self.view.bounds.size.width - )/, , , )];

         [self.view addSubview:imageView];
         [self.session startRunning];
     }
 }

 #pragma mark - AVCaptureMetadataOutputObjectsDelegate代理方法
 - (void)captureOutput:(AVCaptureOutput *)output didOutputMetadataObjects:(NSArray<__kindof AVMetadataObject *> *)metadataObjects fromConnection:(AVCaptureConnection *)connection{
     NSString * str = nil;
     for (AVMetadataObject * obj in metadataObjects) {
         if([obj.type isEqualToString:AVMetadataObjectTypeQRCode]){
             str = [(AVMetadataMachineReadableCodeObject *)obj stringValue];
             [self.session startRunning];
             break;
         }
     }
     self.textField.text = str;
 }

 #pragma mark - UIImagePickerControllerDelegate代理方法
 - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{
     UIImage * image = [info objectForKey:UIImagePickerControllerOriginalImage];

     CIImage * ciimage = [[CIImage alloc]initWithImage:image];
     NSString * str = [QRImage stringFromCiImage:ciimage];
     self.textField.text = str;
     [self dismissViewControllerAnimated:YES completion:nil];
 }

 #pragma mark - 弹出相册
 - (void)presentImagePicker{
     UIImagePickerController * imagePicker = [[UIImagePickerController alloc]init];
     imagePicker.delegate = self;
     [self presentViewController:imagePicker animated:NO completion:nil];
 }

 - (void)didReceiveMemoryWarning {
     [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
 }

 /*
  #pragma mark - Navigation

  // In a storyboard-based application, you will often want to do a little preparation before navigation
  - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
  // Get the new view controller using [segue destinationViewController].
  // Pass the selected object to the new view controller.
  }
  */

 @end

github: https://github.com/pheromone/QRcode

效果如下: