How to Solve problem UIPickerView Fatal error: Index out of range [IOS Swift 5.1 Xcode 11.2]

Question

我正在尝试获取 UIPickerView 的选定值当运行应用程序。但是我得到错误，

Fatal error: Index out of range

我在numberOfRowsInComponent函数中通过print("selected ==>\(selected)")调试。我通过调试得到 selected 的值 0.

如何解决这个问题？

Value From Postman
- Plandate function
http://xxx.xxx.xxx.xx/ProjectService/PODService.svc/GetPlanDate/2
"[  {    \"PlanDate\": \"26/08/2019\",    \"PlanDateFullFormat\": \"20190826\"  },  {    \"PlanDate\": \"27/08/2019\",    \"PlanDateFullFormat\": \"20190827\"  }]"

- PlanShipment
http://xxx.xxx.xxx.xx/ProjectService/PODService.svc/GetShipment/2/20190826
"[  {    \"Shipment\": \"4505023278\"  },  {    \"Shipment\": \"4505023279\"  }]"
http://xxx.xxx.xxx.xx/ProjectService/PODService.svc/GetShipment/2/20190827
"[  {    \"Shipment\": \"4505023244\"  },  {    \"Shipment\": \"4505023274\"  }]"

Return Value From JSON
- Plandate function
http://xxx.xxx.xxx.xx/ProjectService/PODService.svc/GetPlanDate/2
pplandateCategories ==>["20190826", "20190827"]

- PlanShipment
http://xxx.xxx.xxx.xx/ProjectService/PODService.svc/GetShipment/2/20190827
getpShipmentDCPlanData ==>["4505023244", "4505023274"]

Swift
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
      return 2
    }

    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        if component == 0 {
            return pPlandateCategories.count
        }else{
            let selected = pickerview.selectedRow(inComponent:0)
           return pShipmentCategories[selected].count ———>. Thread 1: Fatal error: Index out of range
        }
    }

    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        if component == 0 {
            return pPlandateCategories[row]
        }else{
            let selected = pickerview.selectedRow(inComponent:0)
            return pShipmentCategories[selected][row]
        }
    }

    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        if component == 0{
            pickerview.reloadComponent(1)

        }else{
            let selected = pickerview.selectedRow(inComponent:0)
//            getpPlanDatePickerView.text = "PlanDate:" + " " + pplandateCategories[selected][row]
            someTextField.text = "Shipment:" + " " + pShipmentCategories[selected][row]
        }
    }

Error when Run Project 
My WebService ==> http://xxx.xxx.xxx.xx/ProjectService/PODService.svc/GetPlanDate/2GetPlanDate/2
Fatal error: Index out of range
2019-12-19 10:55:14.459056+0700 pickerDateAndShipment[782:19020] Fatal error: Index out of range

Answer 1

只有当组件的数据异步加载并且数据源在第一次重新加载 table 视图时为空时才会发生崩溃。

为了避免在 pShipmentCategories 数组为空时进行崩溃检查

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    if component == 0 {
        return pPlandateCategories.count
    } else {
        let selected = pickerview.selectedRow(inComponent:0)
        return pShipmentCategories.isEmpty ? 0 : pShipmentCategories[selected].count
    }
}

How to Solve problem UIPickerView Fatal error: Index out of range [IOS Swift 5.1 Xcode 11.2]

How to Solve problem UIPickerView Fatal error: Index out of range [IOS Swift 5.1 Xcode 11.2]

ios

json

uipickerview

swift5.1

xcode11.2