iOS中扫描二维码/生成二维码详解

最近大家总是问我有没有关于二维码的demo,为了满足大家的需求,特此研究了一番,希望能帮到大家!

指示根视图:

1	`self.window.rootViewController = [[UINavigationController alloc]initWithRootViewController:[SecondViewController` `new` `]];`

生成二维码:

// Created by 韩俊强 on 15/11/27.

//

# import "SecondViewController.h"

@interface SecondViewController ()

@property (nonatomic, strong) UITextField *tfCode;

@property (nonatomic, strong) UIButton *btnGenerate;

@property (nonatomic, strong) UIImageView *imageView;

@end

@implementation SecondViewController

- ( void )viewDidLoad {

[ super viewDidLoad];

CGSize windowSize = [UIScreen mainScreen].bounds.size;

self.tfCode = [[UITextField alloc] initWithFrame:CGRectMake( 10 , 64 , windowSize.width- 100 , 40 )];

[self.view addSubview:self.tfCode];

self.tfCode.borderStyle = UITextBorderStyleRoundedRect;

self.btnGenerate = [[UIButton alloc] initWithFrame:CGRectMake(windowSize.width- 100 , 64 , 90 , 40 )];

[self.view addSubview:self.btnGenerate];

[self.btnGenerate addTarget:self action: @selector (actionGenerate) forControlEvents:UIControlEventTouchUpInside];

self.btnGenerate.backgroundColor = [UIColor lightGrayColor];

[self.btnGenerate setTitle:@ "生成" forState:UIControlStateNormal];

[self.btnGenerate setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];

self.imageView = [[UIImageView alloc] initWithFrame:CGRectMake( 0 , 0 , 300 , 300 )];

[self.view addSubview:self.imageView];

self.imageView.center = CGPointMake(windowSize.width/ 2 , windowSize.height/ 2 );

self.tfCode.text = @ "http://www.baidu.com" ;

}

- ( void )actionGenerate

{

NSString *text = self.tfCode.text;

NSData *stringData = [text dataUsingEncoding: NSUTF8StringEncoding];

//生成

CIFilter *qrFilter = [CIFilter filterWithName:@ "CIQRCodeGenerator" ];

[qrFilter setValue:stringData forKey:@ "inputMessage" ];

[qrFilter setValue:@ "M" forKey:@ "inputCorrectionLevel" ];

UIColor *onColor = [UIColor blackColor];

UIColor *offColor = [UIColor whiteColor];

//上色

CIFilter *colorFilter = [CIFilter filterWithName:@ "CIFalseColor" keysAndValues:@ "inputImage" ,qrFilter.outputImage,@ "inputColor0" ,[CIColor colorWithCGColor:onColor.CGColor],@ "inputColor1" ,[CIColor colorWithCGColor:offColor.CGColor],nil];

CIImage *qrImage = colorFilter.outputImage;

//绘制

CGSize size = CGSizeMake( 300 , 300 );

CGImageRef cgImage = [[CIContext contextWithOptions:nil] createCGImage:qrImage fromRect:qrImage.extent];

UIGraphicsBeginImageContext(size);

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextSetInterpolationQuality(context, kCGInterpolationNone);

CGContextScaleCTM(context, 1.0 , - 1.0 );

CGContextDrawImage(context, CGContextGetClipBoundingBox(context), cgImage);

UIImage *codeImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

CGImageRelease(cgImage);

self.imageView.image = codeImage;

}

扫描二维码:

// Created by 韩俊强 on 15/11/27.

//

# import "RootViewController.h"

# import

@interface RootViewController ()

@property (nonatomic, strong) UIView *scanRectView;

// 硬件设备

@property (strong, nonatomic) AVCaptureDevice *device;

//输入设备

@property (strong, nonatomic) AVCaptureDeviceInput *input;

//输出设备

@property (strong, nonatomic) AVCaptureMetadataOutput *output;

//桥梁.连接输入和输出设备,

@property (strong, nonatomic) AVCaptureSession *session;

@property (strong, nonatomic) AVCaptureVideoPreviewLayer *preview;

@end

@implementation RootViewController

- ( void )viewDidLoad {

[ super viewDidLoad];

CGSize windowSize = [UIScreen mainScreen].bounds.size;

CGSize scanSize = CGSizeMake(windowSize.width* 3 / 4 , windowSize.width* 3 / 4 );

CGRect scanRect = CGRectMake((windowSize.width-scanSize.width)/ 2 , (windowSize.height-scanSize.height)/ 2 , scanSize.width, scanSize.height);

scanRect = CGRectMake(scanRect.origin.y/windowSize.height, scanRect.origin.x/windowSize.width, scanRect.size.height/windowSize.height,scanRect.size.width/windowSize.width);

self.device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

self.input = [AVCaptureDeviceInput deviceInputWithDevice:self.device error:nil];

self.output = [[AVCaptureMetadataOutput alloc]init];

[self.output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];

self.session = [[AVCaptureSession alloc]init];

[self.session setSessionPreset:([UIScreen mainScreen].bounds.size.height< 500 )?AVCaptureSessionPreset640x480:AVCaptureSessionPresetHigh];

[self.session addInput:self.input];

[self.session addOutput:self.output];

self.output.metadataObjectTypes=@[AVMetadataObjectTypeQRCode];

self.output.rectOfInterest = scanRect;

self.preview = [AVCaptureVideoPreviewLayer layerWithSession:self.session];

self.preview.videoGravity = AVLayerVideoGravityResizeAspectFill;

self.preview.frame = [UIScreen mainScreen].bounds;

[self.view.layer insertSublayer:self.preview atIndex: 0 ];

self.scanRectView = [UIView new ];

[self.view addSubview:self.scanRectView];

self.scanRectView.frame = CGRectMake( 0 , 0 , scanSize.width, scanSize.height);

self.scanRectView.center = CGPointMake(CGRectGetMidX([UIScreen mainScreen].bounds), CGRectGetMidY([UIScreen mainScreen].bounds));

self.scanRectView.layer.borderColor = [UIColor redColor].CGColor;

self.scanRectView.layer.borderWidth = 1 ;

//开始捕获

[self.session startRunning];

}

- ( void

)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection

{

if ( (metadataObjects.count== 0 ) )

{

return ;

}

if (metadataObjects.count> 0 ) {

[self.session stopRunning];

AVMetadataMachineReadableCodeObject *metadataObject = metadataObjects.firstObject;

//输出扫描字符串

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:metadataObject.stringValue message:@ "" delegate:self cancelButtonTitle:@ "ok" otherButtonTitles: nil];

[alert show];

}

- ( void )alertView:(UIAlertView *)alertView willDismissWithButtonIndex:(NSInteger)buttonIndex

{

[self.session startRunning];

}</avcapturemetadataoutputobjectsdelegate,uialertviewdelegate></avfoundation>

最终效果:(由于扫描二维码无法展示效果,所以自己动手真机测试吧!)

IOS7之前，开发者进行扫码编程时，一般会借助第三方库。常用的是ZBarSDK，IOS7之后，系统的AVMetadataObject类中，为我们提供了解析二维码的接口。经过测试，使用原生API扫描和处理的效率非常高，远远高于第三方库。

一、使用方法示例

官方提供的接口非常简单，代码如下：

@interface ViewController () //用于处理采集信息的代理

{

AVCaptureSession * session; //输入输出的中间桥梁

}

@end

@implementation ViewController

- ( void )viewDidLoad {

[super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

//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];

//设置代理在主线程里刷新

[output setMetadataObjectsDelegate: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];

[session addInput:input];

[session addOutput:output];

//设置扫码支持的编码格式(如下设置条形码和二维码兼容)

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];

//开始捕获

[session startRunning];

}

之后我们的UI上已经可以看到摄像头捕获的内容，只要实现代理中的方法，就可以完成二维码条形码的扫描：

-( void

)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{

if (metadataObjects.count>0) {

//[session stopRunning];

AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjects objectAtIndex : 0 ];

//输出扫描字符串

NSLog(@ "%@" ,metadataObject.stringValue);

}

二、一些优化

通过上面的代码测试，我们可以发现系统的解析处理效率是相当的高，IOS官方提供的API也确实非常强大，然而，我们可以做进一步的优化，将效率更加提高：

首先，AVCaptureMetadataOutput类中有一个这样的属性(在IOS7.0之后可用)：

@property(nonatomic) CGRect rectOfInterest;

这个属性大致意思就是告诉系统它需要注意的区域，大部分APP的扫码UI中都会有一个框，提醒你将条形码放入那个区域，这个属性的作用就在这里，它可以设置一个范围，只处理在这个范围内捕获到的图像的信息。如此一来，可想而知，我们代码的效率又会得到很大的提高，在使用这个属性的时候。需要几点注意：

1、这个CGRect参数和普通的Rect范围不太一样，它的四个值的范围都是0-1，表示比例。

2、经过测试发现，这个参数里面的x对应的恰恰是距离左上角的垂直距离，y对应的是距离左上角的水平距离。

3、宽度和高度设置的情况也是类似。

3、举个例子如果我们想让扫描的处理区域是屏幕的下半部分，我们这样设置

1	`output.rectOfInterest=CGRectMake(0.5,0,0.5, 1);`

具体apple为什么要设计成这样，或者是这个参数我的用法那里不对，还需要了解的朋友给个指导。

转自：http://www.2cto.com/kf/201601/456033.html

另外有一个支持64为编译的二维码生成库下载地址：http://download.csdn.net/download/u011148716/8315981

如果只是生成的話，see
https://github.com/moky/slanissue-ios/blob/master/uikit_ext/S9QRCodeImage.h

用法：

UIImage *qrImage = [UIImage imageWithQRCode:@"你的文字" size:256];