iOS中 扫描二维码/生成二维码详解 韩俊强的博客
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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!
每日更新关注:http://weibo.com/hanjunqiang 新浪微博
指示根视图:
self.window.rootViewController = [[UINavigationController alloc]initWithRootViewController:[SecondViewController new]];
生成二维码:
// Created by 韩俊强 on 15/11/27.// Copyright (c) 2015年 韩俊强. All rights reserved.//#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.// Copyright (c) 2015年 韩俊强. All rights reserved.//#import "RootViewController.h"#import <AVFoundation/AVFoundation.h>@interface RootViewController ()<AVCaptureMetadataOutputObjectsDelegate,UIAlertViewDelegate>@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];}
每日更新关注:http://weibo.com/hanjunqiang 新浪微博
每日更新关注:http://weibo.com/hanjunqiang 新浪微博
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 ()<AVCaptureMetadataOutputObjectsDelegate>
//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
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。
每日更新关注:http://weibo.com/hanjunqiang 新浪微博
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