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!
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指示根视图:
self.window.rootViewController = [[UINavigationController alloc]initWithRootViewController:[SecondViewController new]];
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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];
}
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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!)
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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：
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@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];
}
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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：
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-(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);
}
}
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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
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output.rectOfInterest=CGRectMake(0.5,0,0.5, 1);
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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。
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