原計劃接下來更新UISearchController的文章，應朋友邀請，先更新一篇二維碼掃描的文章吧。

效果圖：

二維碼掃描1.gif

有點太靈敏了。。。

效果如上圖，內部就跳轉相應頁面，外部鏈接直接跳轉Safari，這里就不演示了，用的QRCodeViewController改的，下面上代碼：
.h文件啥都沒有，就不貼了。

代碼：

#import "QRCodeViewController.h"
#import <AVFoundation/AVFoundation.h>

#import "RRZFriendInfoController.h"
#import "RRZInfoDetailPageController.h"

#import "ScanBGView.h"

@interface QRCodeViewController ()<AVCaptureMetadataOutputObjectsDelegate>
@property (weak, nonatomic) IBOutlet UIView *viewPreview;
@property (weak, nonatomic) IBOutlet UILabel *lblStatus;
@property (strong, nonatomic) UILabel *tipLabel;

@property (strong, nonatomic) ScanBGView *myScanBGView;
@property (strong, nonatomic) UIImageView *scanRectView, *lineView;

@property (strong, nonatomic) UIView *boxView;
@property (nonatomic) BOOL isReading;
@property (strong, nonatomic) CALayer *scanLayer;
@property (strong,nonatomic) NSTimer *timer;
-(BOOL)startReading;
-(void)stopReading;

//捕捉會話
@property (nonatomic, strong) AVCaptureSession *captureSession;
//展示layer
@property (nonatomic, strong) AVCaptureVideoPreviewLayer *videoPreviewLayer;
@property (nonatomic, strong) AVCaptureConnection * connection;
@end

@implementation QRCodeViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.title = @"二維碼掃描";
    _captureSession = nil;
    _isReading = NO;
    
    [self startReading];
    [self openUrl]; 
}
#pragma mark 設置焦距
- (void)setFocalLength:(CGFloat)lengthScale
{
    [UIView animateWithDuration:0.5 animations:^{
        [_videoPreviewLayer setAffineTransform:CGAffineTransformMakeScale(lengthScale, lengthScale)];
        _connection.videoScaleAndCropFactor = lengthScale;
    }];
}

-(void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    
    [self.captureSession startRunning];
}

-(void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    
    [self.captureSession stopRunning];
}

-(void)viewDidLayoutSubviews{
    [super viewDidLayoutSubviews];
    self.viewPreview.frame = self.view.bounds;
    [_videoPreviewLayer setFrame:_viewPreview.layer.bounds];
}

//實現startReading方法（這可就是重點咯）
- (BOOL)startReading {
    NSError *error;
    //1.初始化捕捉設備（AVCaptureDevice），類型為AVMediaTypeVideo
    AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    //2.用captureDevice創建輸入流
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];
    if (!input) {
        NSLog(@"%@", [error localizedDescription]);
        return NO;
    }
    //3.創建媒體數據輸出流
    AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];
    //4.實例化捕捉會話
    _captureSession = [[AVCaptureSession alloc] init];
    //4.1.將輸入流添加到會話
    [_captureSession addInput:input];
    //4.2.將媒體輸出流添加到會話中
    [_captureSession addOutput:captureMetadataOutput];
    //5.創建串行隊列，并加媒體輸出流添加到隊列當中
    dispatch_queue_t dispatchQueue;
    dispatchQueue = dispatch_queue_create("myQueue", NULL);
    //5.1.設置代理
    [captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];
    //5.2.設置輸出媒體數據類型為QRCode
    [captureMetadataOutput setMetadataObjectTypes:[NSArray arrayWithObject:AVMetadataObjectTypeQRCode]];
    //6.實例化預覽圖層
    _videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];
    //7.設置預覽圖層填充方式
    [_videoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
    //8.設置圖層的frame
    [_videoPreviewLayer setFrame:_viewPreview.layer.bounds];
    //[_videoPreviewLayer setFrame:self.view.frame];
    //9.將圖層添加到預覽view的圖層上
    [_viewPreview.layer addSublayer:_videoPreviewLayer];
    //10.設置掃描范圍
    captureMetadataOutput.rectOfInterest = CGRectMake(0.2f, 0.2f, 0.8f, 0.8f);
    _connection = [captureMetadataOutput connectionWithMediaType:AVMediaTypeVideo];
    [self setFocalLength:2.0];//1倍正常，2x，3x，4x依次放大
    
    CGFloat width = SCREEN_WIDTH *2/3;
    CGFloat padding = (SCREEN_WIDTH - width)/2;
    CGFloat y = (SCREEN_HEIGHT - width) / 2;
    CGRect scanRect = CGRectMake(padding, y, width, width);
    
    if (!_myScanBGView) {
        _myScanBGView = [[ScanBGView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT)];
        _myScanBGView.backgroundColor = [UIColor colorWithWhite:0 alpha:0.5];
        _myScanBGView.scanRect = scanRect;
    }
    
    if (!_scanRectView) {
        _scanRectView = [[UIImageView alloc] initWithFrame:scanRect];
        _scanRectView.image = [[UIImage imageNamed:@"scan_bg"] resizableImageWithCapInsets:UIEdgeInsetsMake(25, 25, 25, 25)];
        _scanRectView.clipsToBounds = YES;
    }
    if (!_tipLabel) {
        _tipLabel = [UILabel new];
        _tipLabel.textAlignment = NSTextAlignmentCenter;
        _tipLabel.font = [UIFont boldSystemFontOfSize:16];
        _tipLabel.textColor = [[UIColor whiteColor] colorWithAlphaComponent:0.4];
        _tipLabel.text = @"將二維碼放入框內，即可自動掃描";
    }
    if (!_lineView) {
        UIImage *lineImage = [UIImage imageNamed:@"scan_line"];
        CGFloat lineHeight = 2;
        CGFloat lineWidth = CGRectGetWidth(_scanRectView.frame);
        _lineView = [[UIImageView alloc] initWithFrame:CGRectMake(0, -lineHeight, lineWidth, lineHeight)];
        _lineView.contentMode = UIViewContentModeScaleToFill;
        _lineView.image = lineImage;
    }
    
    [self.view.layer addSublayer:_videoPreviewLayer];
    [self.view addSubview:_myScanBGView];
    [self.view addSubview:_scanRectView];
    [self.view addSubview:_tipLabel];
    [_tipLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.right.equalTo(self.view);
        make.top.equalTo(_scanRectView.mas_bottom).offset(20);
        make.height.mas_equalTo(30);
    }];
    [_scanRectView addSubview:_lineView];    //提示label

    [self scanLineStartAction];
    
    //11.開始掃描
    [_captureSession startRunning];
    return YES;
}

- (void)scanLineStartAction{
    [self scanLineStopAction];
    
    CABasicAnimation *scanAnimation = [CABasicAnimation animationWithKeyPath:@"position.y"];
    scanAnimation.fromValue = @(-CGRectGetHeight(_lineView.frame));
    scanAnimation.toValue = @(CGRectGetHeight(_lineView.frame) + CGRectGetHeight(_scanRectView.frame));
    
    scanAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    scanAnimation.repeatCount = CGFLOAT_MAX;
    scanAnimation.duration = 2.0;
    [self.lineView.layer addAnimation:scanAnimation forKey:@"basic"];
}

- (void)scanLineStopAction{
    [self.lineView.layer removeAllAnimations];
}

//實現AVCaptureMetadataOutputObjectsDelegate協議方法
#pragma mark - AVCaptureMetadataOutputObjectsDelegate
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
    //判斷是否有數據
    if (metadataObjects != nil && [metadataObjects count] > 0) {
        AVMetadataMachineReadableCodeObject *metadataObj = [metadataObjects objectAtIndex:0];
        //判斷回傳的數據類型
        if ([[metadataObj type] isEqualToString:AVMetadataObjectTypeQRCode]) {
            [_lblStatus performSelectorOnMainThread:@selector(setText:) withObject:[metadataObj stringValue] waitUntilDone:NO];
            
            
            [self performSelectorOnMainThread:@selector(stopReading) withObject:nil waitUntilDone:NO];
            
            _isReading = NO;
        }
    }
    // NSLog(@" 外 url is %@",_lblStatus.text);
    
}
//實現計時器方法moveScanLayer:(NSTimer *)timer
- (void)moveScanLayer:(NSTimer *)timer
{
    CGRect frame = _scanLayer.frame;
    if (_boxView.frame.size.height < _scanLayer.frame.origin.y+25) {
        frame.origin.y = 0;
        _scanLayer.frame = frame;
    }else{
        frame.origin.y += 25;
        [UIView animateWithDuration:0.1 animations:^{
            _scanLayer.frame = frame;
        }];
    }  
}

- (void)openUrl {
  
    NSLog(@"---------得到網址:%@-------",self.lblStatus.text);
    NSString *resultAsString = self.lblStatus.text;
    if (resultAsString.length > 0) {
        //震動反饋
        AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
        
        NSString *parametersType = [self jiexi:@"type" webaddress:resultAsString];
        NSString *parametersId = [self jiexi:@"id" webaddress:resultAsString];
        if ([parametersType isEqualToString:@"yryzcust"]) {
            RRZFriendInfoController *friendInfoController = [[RRZFriendInfoController alloc]init];
            friendInfoController.superiorType = 10;
            friendInfoController.custId = parametersId;
            [self.navigationController pushViewController:friendInfoController animated:YES];
        }else if([parametersType isEqualToString:@"yryzinfo"]){
            RRZInfoDetailPageController *detailPageController = [[RRZInfoDetailPageController alloc]init];
            detailPageController.superiorType = 10;
            detailPageController.infoID = parametersId;
            [self.navigationController pushViewController:detailPageController animated:YES];
        }else{
            NSURL *url = [NSURL URLWithString:self.lblStatus.text];
            if ([[UIApplication sharedApplication]canOpenURL:url]) {
                [[UIApplication sharedApplication]openURL:url];
            }else{
                [MBProgressHUD showError:@"無法識別該二維碼" toView:self.view];
            }
            
            [self.navigationController popViewControllerAnimated:YES];
        }
    }
}

-(void)stopReading{
    [_captureSession stopRunning];
    _captureSession = nil;
    [_scanLayer removeFromSuperlayer];
    [_videoPreviewLayer removeFromSuperlayer];
    [self openUrl];
}

    
#pragma mark - NSString
    
/**
 *  @author yichao, 16-04-21 11:04:39
 *
 *  從URL中獲取參數
 *
 *  @param CS         參數名稱
 *  @param webaddress URL
 *
 *  @return 參數
 */
-(NSString *) jiexi:(NSString *)CS webaddress:(NSString *)webaddress
{
    NSError *error;
    NSString *regTags=[[NSString alloc] initWithFormat:@"(^|&|\\?)+%@=+([^&]*)(&|$)",CS];
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:regTags
                                                                           options:NSRegularExpressionCaseInsensitive
                                                                             error:&error];
    
    // 執行匹配的過程
    // NSString *webaddress=@"http://www.baidu.com/dd/adb.htm?adc=e12&xx=lkw&dalsjd=12";
    NSArray *matches = [regex matchesInString:webaddress
                                      options:0
                                        range:NSMakeRange(0, [webaddress length])];
    for (NSTextCheckingResult *match in matches) {
        //NSRange matchRange = [match range];
        //NSString *tagString = [webaddress substringWithRange:matchRange];  // 整個匹配串
        //        NSRange r1 = [match rangeAtIndex:1];
        //        if (!NSEqualRanges(r1, NSMakeRange(NSNotFound, 0))) {    // 由時分組1可能沒有找到相應的匹配，用這種辦法來判斷
        //            //NSString *tagName = [webaddress substringWithRange:r1];  // 分組1所對應的串
        //            return @"";
        //        }
        
        NSString *tagValue = [webaddress substringWithRange:[match rangeAtIndex:2]];  // 分組2所對應的串
        //    NSLog(@"分組2所對應的串:%@\n",tagValue);
        return tagValue;
    }
    return @"";
}

@end

all，不清楚的歡迎留言。