IOS scan QR Code, barcode implementation

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>
@interface Viewcontroller () <AVCaptureMetadataOutputObjectsDelegate>
@property (Weak, nonatomic) Iboutlet UILabel *capturelabel;
@property (strong,nonatomic) avcapturesession *session; Capture session
@property (strong,nonatomic) Avcapturevideopreviewlayer *previewlayer; The layer generated by the QR code
@end

@implementation Viewcontroller

-(void) Viewdidload {
[Super Viewdidload];
Additional setup after loading the view, typically from a nib.
}

-(void) didreceivememorywarning {
[Super didreceivememorywarning];
Dispose of any resources the can be recreated.
}
#pragma mark-read QR code
-(void) Readqrcode
{
1. Camera devices
Avcapturedevice *device = [Avcapturedevice defaultdevicewithmediatype:avmediatypevideo];

2. Set input
Because the simulator doesn't have a camera, it's best to make a judgment here.
Nserror *error = nil;
Avcapturedeviceinput *input = [Avcapturedeviceinput deviceinputwithdevice:device error:&error];
if (Error) {
NSLog (@ "No webcam-%@", error.localizeddescription);
Return
}

3. Set output (metadata meta data)
Avcapturemetadataoutput *output = [[Avcapturemetadataoutput alloc] init];
3.1 Setting the proxy for the output
Description: Using the main thread queue, the corresponding synchronization, the use of other queues, corresponding to different steps, it is easy for users to produce a bad experience setmetadataobjectsdelegate
[Output Setmetadataobjectsdelegate:self queue:dispatch_get_main_queue ()];

4. Shooting session
Avcapturesession *session = [[Avcapturesession alloc] init];
Add input and output to session
[Session Addinput:input];
[Session Addoutput:output];

4.1 Setting the format of the output
Tip: Be sure to specify the output metadata type after you set the output of the session to output!
[Output SETMETADATAOBJECTTYPES:@[AVMETADATAOBJECTTYPEQRCODE]];

5. Set up a preview layer (to allow users to see the scan condition)
Avcapturevideopreviewlayer *preview = [Avcapturevideopreviewlayer layerwithsession:session];

5.1 Setting the properties of the preview layer
[Preview Setvideogravity:avlayervideogravityresizeaspectfill];

5.2 Setting the size of the preview layer
[Preview SetFrame:self.view.bounds];

5.3 Adding layers to a view's layer
[Self.view.layer Insertsublayer:preview atindex:0];
Self.previewlayer = preview;

6. Start session
[Session startrunning];

Self.session = session;
}

#pragma mark-Output proxy method
This method is recognized in the QRCode, and the conversion is completed
If the content of the QRCode is larger, the longer the conversion takes
-(void) Captureoutput: (Avcaptureoutput *) captureoutput didoutputmetadataobjects: (Nsarray *) metadataobjects Fromconnection: (avcaptureconnection *) connection
{
Frequent scans, invoking proxy methods
1. If the scan is complete, stop the session
[Self.session stoprunning];
2. Delete a preview layer
[Self.previewlayer Removefromsuperlayer];

NSLog (@ "%@", metadataobjects);

3. Set interface to display scan results
if (Metadataobjects.count > 0) {
Avmetadatamachinereadablecodeobject *obj = metadataobjects[0];
Tip: If you need to scan for information such as URLs or business cards, you can expand here!
_capturelabel.text = Obj.stringvalue;
}} @end

IOS scan QR Code, barcode implementation