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qt for ios扫描二维码功能实现

2015-04-15 15:06 525 查看

问题:　　

公司项目考虑到跨平台一直都是用qt做,由于项目需求,项目上要增加一个二维码扫描功能,在安卓可以用QVideoProbe实现抓取摄像头视频帧,用QZxing解码图片,从而实现二维码扫描,但是在ios上,QVideProbe并不支持,所以只好选择其他抓取视频帧的方法,考虑使用OPencv实现抓取视频帧,但是在查看ios文档时,ios7以上直接支持二维码扫描功能,所以放弃使用opencv抓取+zxing解码的方法.从而采取ios官方提供的二维码解码功能.

实现:

由于我们项目ui一直是用qml实现,但是要实现扫描二维码功能,需要调用AVFoundation中的方法,同时要显示ios中的ui显示摄像头及返回qml键.所以这里需要结合oc和qt编程.

直接上代码:

pro文件增加

ios{

　　OBJECTIVE_SOURCES+=IOSView.mm　　\#objectc++file

　　　　　　IOSCamera.mm　

　　HEADER+=　IOSView.h\

　　　　　　IOSCamera.h\

　　　　　　IOSCameraViewProtocol.h　

　　QMAKE_LFLAGS+=-frameworkAVFoundation　　#addAVfoundationframework

　　QT+=guiprivate

}

重新qmake生成xcodeproject

IOSView.#include<QQuickItem>

classIOSView:publicQQuickItem { Q_OBJECT Q_PROPERTY(QStringqrcodeTextREADqrcodeTextWRITEsetQrcodeTextNOTIFYqrcodeTextChanged) public: explicitIOSView(QQuickItem*parent=0); QStringqrcodeText(){ returnm_qrcodeText; } voidsetQrcodeText(QStringtext){ m_qrcodeText=text; emitqrcodeTextChanged(); } QStringm_qrcodeText; publicslots: voidstartScan();　　//foropenioscamerascanandui private: void*m_delegate;　　//forcommunicationwithqt signals: voidqrcodeTextChanged();　　 voidstopCameraScan();　　//showqml };

IOSView..mm

#include<UIKit/UIKit.h> #include<QtQuick> #include<QtGui> #include<QtGui/qpa/qplatformnativeinterface.h> #include"IOSView.h" #include"IOSCamera.h" @interfaceIOSCameraDelegate:NSObject<IOSCameraProtocol>{ IOSView*m_iosView; } @end @implementationIOSCameraDelegate -(id)initWithIOSCamera:(IOSView*)iosView { self=[superinit]; if(self){ m_iosView=iosView; } returnself; } -(void)scanCancel{ emitm_iosView->stopCameraScan(); } -(void)scanResult:(NSString*)result{ m_iosView->setQrcodeText(QString::fromNSString(result)); } @end IOSView::IOSView(QQuickItem*parent): QQuickItem(parent),m_delegate([[IOSCameraDelegatealloc]initWithIOSCamera:this]) { } voidIOSView::startScan() { //GettheUIViewthatbacksourQQuickWindow: UIView*view=static_cast<UIView*>(QGuiApplication::platformNativeInterface()->nativeResourceForWindow("uiview",window())); UIViewController*qtController=[[viewwindow]rootViewController]; IOSCamera*iosCamera=[[[IOSCameraViewalloc]init]autorelease]; iosCamera.delegate=(id)m_delegate; //Telltheimagecontrollertoanimateontop: [qtControllerpresentViewController:iosCameraanimated:YEScompletion:nil]; [iosCamerastartScan]; }

　　

IOSCameraViewProtocol.h

#import<Foundation/Foundation.h> @protocolCameraScanViewProtocol<NSObject> @required -(void)scanCancel; -(void)scanResult:(NSString*)result; @end

　　

IOSCamera.h

#import<UIKit/UIKit.h> #import<AVFoundation/AVFoundation.h> #import"CameraViewProtocol.h" @interfaceIOSCamera:UIViewController<AVCaptureMetadataOutputObjectsDelegate>{ id<CameraScanViewProtocol>delegate; } @property(retain,nonatomic)IBOutletUIView*viewPreview; -(IBAction)backQtApp:(id)sender; -(void)startScan; @property(retain)id<CameraScanViewProtocol>delegate; @end

　　

IOSCamera.cpp#import"IOSCamera.h"

@interfaceIOSCamera()
@property(nonatomic,strong)AVCaptureSession*captureSession;
@property(nonatomic,strong)AVCaptureVideoPreviewLayer*videoPreviewLayer;-(BOOL)startReading;
-(void)stopReading;
-(void)openQtLayer;
@end

@implementationCameraScanView
@synthesizedelegate;　　　　//Syncdelegateforinteractivewithqt

-(void)viewDidLoad{
[superviewDidLoad];
//Doanyadditionalsetupafterloadingtheviewfromitsnib.

//InitiallymakethecaptureSessionobjectnil.
_captureSession=nil;

//SettheinitialvalueoftheflagtoNO.
_isReading=NO;

//Beginloadingthesoundeffectsotohaveitreadyforplaybackwhenit'sneeded.
[selfloadBeepSound];

}

-(void)didReceiveMemoryWarning{
[superdidReceiveMemoryWarning];
//Disposeofanyresourcesthatcanberecreated.
}

/*
#pragmamark-Navigation

-(void)dealloc{
[_viewPreviewrelease];
[superdealloc];
}
-(void)viewDidUnload{
[selfsetViewPreview:nil];
[superviewDidUnload];
}-(IBAction)backQtApp:(id)sender{[delegatescanCancel];

[selfstopReading];
}

-(void)openQtLayer{
//BringbackQt'sviewcontroller:
UIViewController*rvc=[[[UIApplicationsharedApplication]keyWindow]rootViewController];
[rvcdismissViewControllerAnimated:YEScompletion:nil];
}

-(void)startScan{
if(!_isReading){
//ThisisthecasewheretheappshouldreadaQRcodewhenthestartbuttonistapped.
if([selfstartReading]){
//IfthestartReadingmethodsreturnsYESandthecapturesessionissuccessfully
//running,thenchangethestartbuttontitleandthestatusmessage.
NSLog(@"StartReading!!");
}
}
}

#pragmamark-Privatemethodimplementation

-(BOOL)startReading{
NSError*error;

//GetaninstanceoftheAVCaptureDeviceclasstoinitializeadeviceobjectandprovidethevideo
//asthemediatypeparameter.
AVCaptureDevice*captureDevice=[AVCaptureDevicedefaultDeviceWithMediaType:AVMediaTypeVideo];

//GetaninstanceoftheAVCaptureDeviceInputclassusingthepreviousdeviceobject.
AVCaptureDeviceInput*input=[AVCaptureDeviceInputdeviceInputWithDevice:captureDeviceerror:&error];

if(!input){
//Ifanyerroroccurs,simplylogthedescriptionofitanddon'tcontinueanymore.
NSLog(@"%@",[errorlocalizedDescription]);
returnNO;
}

//InitializethecaptureSessionobject.
_captureSession=[[AVCaptureSessionalloc]init];
//Settheinputdeviceonthecapturesession.
[_captureSessionaddInput:input];

//InitializeaAVCaptureMetadataOutputobjectandsetitastheoutputdevicetothecapturesession.
AVCaptureMetadataOutput*captureMetadataOutput=[[AVCaptureMetadataOutputalloc]init];
[_captureSessionaddOutput:captureMetadataOutput];

//Createanewserialdispatchqueue.
dispatch_queue_tdispatchQueue;
dispatchQueue=dispatch_queue_create("myQueue",NULL);
[captureMetadataOutputsetMetadataObjectsDelegate:selfqueue:dispatchQueue];
[captureMetadataOutputsetMetadataObjectTypes:[NSArrayarrayWithObject:AVMetadataObjectTypeQRCode]];

//InitializethevideopreviewlayerandadditasasublayertotheviewPreviewview'slayer.
_videoPreviewLayer=[[AVCaptureVideoPreviewLayeralloc]initWithSession:_captureSession];
[_videoPreviewLayersetVideoGravity:AVLayerVideoGravityResizeAspectFill];
[_videoPreviewLayersetFrame:_viewPreview.layer.bounds];
[_viewPreview.layeraddSublayer:_videoPreviewLayer];

//Startvideocapture.
[_captureSessionstartRunning];
_isReading=YES;
returnYES;
}

-(void)stopReading{
//Stopvideocaptureandmakethecapturesessionobjectnil.
[_captureSessionstopRunning];
_captureSession=nil;

//RemovethevideopreviewlayerfromtheviewPreviewview'slayer.
[_videoPreviewLayerremoveFromSuperlayer];
_isReading=NO;
[selfopenQtLayer];
}

#pragmamark-AVCaptureMetadataOutputObjectsDelegatemethodimplementation

-(void)captureOutput:(AVCaptureOutput*)captureOutputdidOutputMetadataObjects:(NSArray*)metadataObjectsfromConnection:(AVCaptureConnection*)connection{

//CheckifthemetadataObjectsarrayisnotnilanditcontainsatleastoneobject.
if(metadataObjects!=nil&&[metadataObjectscount]>0){
//Getthemetadataobject.
AVMetadataMachineReadableCodeObject*metadataObj=[metadataObjectsobjectAtIndex:0];
if([[metadataObjtype]isEqualToString:AVMetadataObjectTypeQRCode]){
//IfthefoundmetadataisequaltotheQRcodemetadatathenupdatethestatuslabel'stext,
//stopreadingandchangethebarbuttonitem'stitleandtheflag'svalue.
//Everythingisdoneonthemainthread.
[delegatescanResult:[metadataObjstringValue]];　　//sendscanresulttoqtshow

[selfperformSelectorOnMainThread:@selector(stopReading)withObject:nilwaitUntilDone:NO];

_isReading=NO;
}
}
}

@end

OK.大概流程就这些了,添加xib文件等就不介绍了.

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