为什么uipickerview错误：尝试调用-CellForrowatIndExpath：在更新其可见单元格过程中的表视图上？

Question

打开uipickerview时会遇到错误。 我的Uipickerview有16个项目。

    func open_activity_picker()
{
    activity_UIPickerView = UIPickerView()

        activity_UIPickerView.delegate = self
        activity_UIPickerView.dataSource = self
        activity_UIPickerView.backgroundColor = UIColor.white
        activity_UIPickerView.setValue(UIColor.black, forKey: "textColor")
        activity_UIPickerView.autoresizingMask = .flexibleWidth
        activity_UIPickerView.contentMode = .center
        activity_UIPickerView.frame = CGRect.init(    x: 0.0, 
                                                    y: 10,       //UIScreen.main.bounds.size.height - 300, 
                                                    width: UIScreen.main.bounds.size.width, 
                                                    height: 300)
        self.view.addSubview(activity_UIPickerView)
}

func numberOfComponents(in pickerView: UIPickerView) -> Int 
{
        return 1  // total picker columns 
}


func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int 
{
    return 16
}


func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? 
{
            var activity_title = ""
            var nmbr_activity_title = ""
        switch( row )
        {
            case 0:          activity_title = "aerobics               ";      nmbr_activity_title = " 1. aerobics               "
            case 1:          activity_title = "bike (mountain)          ";      nmbr_activity_title = " 2. bike (mountain)        "
            case 2:          activity_title = "bike (street)            ";      nmbr_activity_title = " 3. bike (street)          "
            case 3:          activity_title = "calisthenics           ";      nmbr_activity_title = " 4. calisthenics           "
            case 4:          activity_title = "golf 9 holes           ";      nmbr_activity_title = " 5. golf 9 holes           "
            case 5:          activity_title = "golf 18 holes          ";      nmbr_activity_title = " 6. golf 18 holes          "
            case 6:          activity_title = "hike moderate          ";      nmbr_activity_title = " 7. hike moderate        "
            case 7:          activity_title = "hike strenuous         ";      nmbr_activity_title = " 8. hike strenuous       "
            case 8:          activity_title = "jog                    ";      nmbr_activity_title = " 9. jog                    "
            case 9:          activity_title = "karate kata";      nmbr_activity_title = "10. karate kata"
            case 10:         activity_title = "run";      nmbr_activity_title = "11. run"
            case 11:         activity_title = "stationary exercises";      nmbr_activity_title = "12. stationary exercises"
            case 12:         activity_title = "swim";      nmbr_activity_title = "13. swim"
            case 13:         activity_title = "treadmill";      nmbr_activity_title = "14. treadmill"
            case 14:         activity_title = "walk";      nmbr_activity_title = "15. walk"
            case 15:         activity_title = "woopie";      nmbr_activity_title = "16. woopie"
            default:
                handle_fault("")
        }
        activity_title = TRIM( activity_title )
        activity_title = activity_title.replacingOccurrences(of: " ", with: "_", options: .literal, range: nil)
        activity_selection_types[ row ] = activity_title 


        // Select boot default if no activity selected?
        if activity_selection_type == ""   &&   row == 0
        {
            activity_selection_type = activity_title
        }
        // row is previous user selection of activity_selection_type?
        if activity_title == activity_selection_type
        {
            activity_UIPickerView.selectRow( row, inComponent: component, animated: true)
        }

        return( TRIM( nmbr_activity_title    ))
    }

输出 - - - - - - - - - - - - - - - - - - - - - - - - - ----（对不起，stacko删除了lineFeeds）

open_activity_picker()...  

编号components：1
编号：1
numberFrowsIncomponent：16
numberFrowsIncomponent：16
numberFrowsIncomponent：16
numberFrowsIncomponent：16
numberFrowsIncomponent：16
numberFrowsIncomponent：16
编号：1
numberFrowsIncomponent：16
--------第0行Anerobics Activity_Selection_type：自行车_（山）
--------第1行自行车_（山）活动_selection_type：自行车_（山） 2022-06-27 09：53：36.183633-0700 kp_to_ios_5 [38198：1313788] [servert]试图致力于调用-cellforrowatAtindIndExpath：在表视图上，在更新其可见单元格的过程中，不允许使用该单元。在uitaiteViewAlertForcellForrowAtatIndExpathAccessDuringUpdate上进行符号断点，以在调试器中捕捉到这一点，并查看导致这种情况的原因。也许您正在尝试从表内部的表查看表查看特定行的回调？表视图：＆lt; uipickertableView：0x14802b400;帧=（9 -170.667; 675 375）;不透明=否; GesturerEcognizers =＆lt; nSarray：0x2810fdb00＆gt;;; layer =＆lt; calayer：0x281ef5080＆gt;; ContentOffSet：{0，-171.6666666666666}; contentsize：{675，512}; AdjustedContentInset：{171.66666666666666，0，171.33333333333334，0}; DataSource：＆lt; uipickercolumnview：0x1475132f0;帧=（0 0; 693 300）;自动化= W+TM+H; gesturerEcognizers =＆lt; nsarray：0x2810da970＆gt;;; layer =＆lt; calayer：0x281ef7ea0＆gt;＆gt;＆gt;