Ios 如何使相机功能仅显示在一个选项卡栏项中？_Ios_Swift

Ios 如何使相机功能仅显示在一个选项卡栏项中？

ios swift

Ios 如何使相机功能仅显示在一个选项卡栏项中？,ios,swift,Ios,Swift,我目前正在Xcode 10中创建一个QR扫描仪/阅读器应用程序。我有一个选项卡控制器，它有两个选项卡栏项 1）家 2.）QR扫描仪虽然我的代码可以工作，我可以在“第二视图控制器”中扫描二维码，但每当我切换到“第一视图控制器”时，它仍然会在我不想扫描二维码时扫描二维码。如果您对我如何解决这个问题有任何建议，我们将不胜感激第一视图控制器： import UIKit class FirstViewController: UIViewController{ override func vi

我目前正在Xcode 10中创建一个QR扫描仪/阅读器应用程序。我有一个选项卡控制器，它有两个选项卡栏项

1）家

2.）QR扫描仪

虽然我的代码可以工作，我可以在“第二视图控制器”中扫描二维码，但每当我切换到“第一视图控制器”时，它仍然会在我不想扫描二维码时扫描二维码。如果您对我如何解决这个问题有任何建议，我们将不胜感激

第一视图控制器：

import UIKit

class FirstViewController: UIViewController{
    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

import UIKit
import AVFoundation

class SecondViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
    var video = AVCaptureVideoPreviewLayer()

    @IBOutlet weak var square: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        //Creating session
        let session = AVCaptureSession()

        //Define Capture device
        let captureDevice = AVCaptureDevice.default(for: AVMediaType.video)

        do {
            let input = try AVCaptureDeviceInput(device: captureDevice!)
            session.addInput(input)
        } catch {
            print (">>>>Error")
        }

        let output = AVCaptureMetadataOutput ()
        session.addOutput(output)

        output.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)

        output.metadataObjectTypes = [AVMetadataObject.ObjectType.qr]

        video = AVCaptureVideoPreviewLayer(session: session)
        video.frame = view.layer.bounds
        view.layer.addSublayer(video)

        self.view.bringSubviewToFront(square)

        session.startRunning()
    }

    func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
        if metadataObjects != nil && metadataObjects.count != 0 {
            if let object = metadataObjects[0] as? AVMetadataMachineReadableCodeObject{
                if object.type == AVMetadataObject.ObjectType.qr{
                    let alert = UIAlertController(title: "QR code", message: object.stringValue, preferredStyle: .alert)
                    alert.addAction(UIAlertAction(title: "Retake", style: .default, handler: nil))

                    present(alert,animated: true, completion: nil)
                }
            }
        }
    }
}

class SecondViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

    let session = AVCaptureSession()

    override func viewDidLoad() {
        // any setup you may need
    }

    override func viewWillAppear(_ animated: Bool) {
        session.startRunning()
        print("Start running")
    }

    override func viewDidDisappear(_ animated: Bool) {
        session.stopRunning()
        print ("Stop running")
    }

}

第二视图控制器：

import UIKit

class FirstViewController: UIViewController{
    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

import UIKit
import AVFoundation

class SecondViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
    var video = AVCaptureVideoPreviewLayer()

    @IBOutlet weak var square: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        //Creating session
        let session = AVCaptureSession()

        //Define Capture device
        let captureDevice = AVCaptureDevice.default(for: AVMediaType.video)

        do {
            let input = try AVCaptureDeviceInput(device: captureDevice!)
            session.addInput(input)
        } catch {
            print (">>>>Error")
        }

        let output = AVCaptureMetadataOutput ()
        session.addOutput(output)

        output.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)

        output.metadataObjectTypes = [AVMetadataObject.ObjectType.qr]

        video = AVCaptureVideoPreviewLayer(session: session)
        video.frame = view.layer.bounds
        view.layer.addSublayer(video)

        self.view.bringSubviewToFront(square)

        session.startRunning()
    }

    func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
        if metadataObjects != nil && metadataObjects.count != 0 {
            if let object = metadataObjects[0] as? AVMetadataMachineReadableCodeObject{
                if object.type == AVMetadataObject.ObjectType.qr{
                    let alert = UIAlertController(title: "QR code", message: object.stringValue, preferredStyle: .alert)
                    alert.addAction(UIAlertAction(title: "Retake", style: .default, handler: nil))

                    present(alert,animated: true, completion: nil)
                }
            }
        }
    }
}

class SecondViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

    let session = AVCaptureSession()

    override func viewDidLoad() {
        // any setup you may need
    }

    override func viewWillAppear(_ animated: Bool) {
        session.startRunning()
        print("Start running")
    }

    override func viewDidDisappear(_ animated: Bool) {
        session.stopRunning()
        print ("Stop running")
    }

}

您已启动

AVCaptureSession

会话，但未明确停止它。在控制器之间切换时，系统可能会将控制器保留在内存中

在离开控制器并进行清理之前，您需要执行

session.stopRunning（）

。例如，在

视图中将消失或类似
Ref:
您已经启动了AVCaptureSession
会话，但没有明确停止它。在控制器之间切换时，系统可能会将控制器保留在内存中
在离开控制器并进行清理之前，您需要执行session.stopRunning（）
。例如，在视图中将消失或类似
Ref:
我建议将会话作为成员变量添加到类中，而不仅仅是viewDidLoad（）方法
现在，在ViewWillAspect（）方法中，您可以调用session.startRunning（），在ViewWillEnglish中，您可以调用session.stopRunning（）
以下是一个基本布局：
class SecondViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
    let session = AVCaptureSession()

    override func viewDidLoad() {
        // any setup you may need
    }

    override func viewWillAppear() {
        // ensure everything is setup correctly

        session.startRunning()
    }

    override func viewWillDisappear() {
        // anything before navigating away

        session.stopRunning()
    }
}

我建议将会话作为成员变量添加到类中，而不仅仅是viewDidLoad（）方法
现在，在ViewWillAspect（）方法中，您可以调用session.startRunning（），在ViewWillEnglish中，您可以调用session.stopRunning（）
以下是一个基本布局：
class SecondViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
    let session = AVCaptureSession()

    override func viewDidLoad() {
        // any setup you may need
    }

    override func viewWillAppear() {
        // ensure everything is setup correctly

        session.startRunning()
    }

    override func viewWillDisappear() {
        // anything before navigating away

        session.stopRunning()
    }
}

谢谢大家的帮助。在查看代码后，我意识到我要做的是重写viewdidappease（）和viewdiddefine（）
工作代码：
import UIKit

class FirstViewController: UIViewController{
    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

import UIKit
import AVFoundation

class SecondViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
    var video = AVCaptureVideoPreviewLayer()

    @IBOutlet weak var square: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        //Creating session
        let session = AVCaptureSession()

        //Define Capture device
        let captureDevice = AVCaptureDevice.default(for: AVMediaType.video)

        do {
            let input = try AVCaptureDeviceInput(device: captureDevice!)
            session.addInput(input)
        } catch {
            print (">>>>Error")
        }

        let output = AVCaptureMetadataOutput ()
        session.addOutput(output)

        output.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)

        output.metadataObjectTypes = [AVMetadataObject.ObjectType.qr]

        video = AVCaptureVideoPreviewLayer(session: session)
        video.frame = view.layer.bounds
        view.layer.addSublayer(video)

        self.view.bringSubviewToFront(square)

        session.startRunning()
    }

    func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
        if metadataObjects != nil && metadataObjects.count != 0 {
            if let object = metadataObjects[0] as? AVMetadataMachineReadableCodeObject{
                if object.type == AVMetadataObject.ObjectType.qr{
                    let alert = UIAlertController(title: "QR code", message: object.stringValue, preferredStyle: .alert)
                    alert.addAction(UIAlertAction(title: "Retake", style: .default, handler: nil))

                    present(alert,animated: true, completion: nil)
                }
            }
        }
    }
}

class SecondViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

    let session = AVCaptureSession()

    override func viewDidLoad() {
        // any setup you may need
    }

    override func viewWillAppear(_ animated: Bool) {
        session.startRunning()
        print("Start running")
    }

    override func viewDidDisappear(_ animated: Bool) {
        session.stopRunning()
        print ("Stop running")
    }

}

谢谢大家的帮助。在查看代码后，我意识到我要做的是重写viewdidappease（）和viewdiddefine（）
工作代码：
import UIKit

class FirstViewController: UIViewController{
    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

import UIKit
import AVFoundation

class SecondViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
    var video = AVCaptureVideoPreviewLayer()

    @IBOutlet weak var square: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        //Creating session
        let session = AVCaptureSession()

        //Define Capture device
        let captureDevice = AVCaptureDevice.default(for: AVMediaType.video)

        do {
            let input = try AVCaptureDeviceInput(device: captureDevice!)
            session.addInput(input)
        } catch {
            print (">>>>Error")
        }

        let output = AVCaptureMetadataOutput ()
        session.addOutput(output)

        output.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)

        output.metadataObjectTypes = [AVMetadataObject.ObjectType.qr]

        video = AVCaptureVideoPreviewLayer(session: session)
        video.frame = view.layer.bounds
        view.layer.addSublayer(video)

        self.view.bringSubviewToFront(square)

        session.startRunning()
    }

    func metadataOutput(_ output: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
        if metadataObjects != nil && metadataObjects.count != 0 {
            if let object = metadataObjects[0] as? AVMetadataMachineReadableCodeObject{
                if object.type == AVMetadataObject.ObjectType.qr{
                    let alert = UIAlertController(title: "QR code", message: object.stringValue, preferredStyle: .alert)
                    alert.addAction(UIAlertAction(title: "Retake", style: .default, handler: nil))

                    present(alert,animated: true, completion: nil)
                }
            }
        }
    }
}

class SecondViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {

    let session = AVCaptureSession()

    override func viewDidLoad() {
        // any setup you may need
    }

    override func viewWillAppear(_ animated: Bool) {
        session.startRunning()
        print("Start running")
    }

    override func viewDidDisappear(_ animated: Bool) {
        session.stopRunning()
        print ("Stop running")
    }

}

我会很快让您知道我的结果。@tharriott如果这对您有帮助，请将其标记为已批准的答案：）在您的示例中，您正在覆盖viewDidLoad
twiceWhoops！多谢各位@PeterPajchlI将很快让您知道我的结果。@tharriott如果这对您有帮助，请将其标记为已批准的答案：）在您的示例中，您正在覆盖viewDidLoad
twiceWhoops！多谢各位@彼得帕奇勒