         }
         // 3、将输入和输出都添加到会话中
         session.addInput(deviceInput)
-        print(output.metadataObjectTypes)
+        print(output.availableMetadataObjectTypes)
         session.addOutput(output)
-        print(output.metadataObjectTypes)
+        print(output.availableMetadataObjectTypes)
         // 4、设置输出能够解析的数据类型
         // 注意：设置能够解析的数据类型，一定要在输出对象添加到会话之后设置，否则会报错
         output.metadataObjectTypes = output.availableMetadataObjectTypes

import AVFoundation

class QRCodeViewController: UIViewController, UITabBarDelegate {

    @IBAction func closeBtnClick(sender: AnyObject) {
        dismissViewControllerAnimated(true, completion: nil)
    }
    
    // 冲击波视图
    @IBOutlet weak var scanLineView: UIImageView!

    @IBOutlet weak var containerHeightCons: NSLayoutConstraint!
    // 冲击波视图顶部约束
    @IBOutlet weak var scanLineCons: NSLayoutConstraint!
    
    @IBAction func closeBtnClick(sender: AnyObject) {
        dismissViewControllerAnimated(true, completion: nil)
    }
    
    // 底部视图
    @IBOutlet weak var customTabBar: UITabBar!
    override func viewDidLoad() {
