Question

我试图将现有的表视图指向新的DynamoDB数据库。 AWS DynamoDB调用在表视图中填充了一个字典变量数组，但模拟器正在显示数据。我花了几天的时间尝试使用异步函数调用来完成闭包，但没有成功。现在，我摆脱了自定义功能，直接在表视图的viewDidLoad（）中使用AWS闭包。任何帮助表示赞赏。

这是表格视图代码：

override func viewDidLoad() {
    super.viewDidLoad()

    //dynamodb call
    let dynamoDBObjectMapper = AWSDynamoDBObjectMapper.default()
    let scanExpression = AWSDynamoDBScanExpression()
    scanExpression.limit = 20

    dynamoDBObjectMapper.scan(Employees.self, expression: scanExpression).continueWith(block: { (task:AWSTask<AWSDynamoDBPaginatedOutput>!) -> Any? in

        if let error = task.error as NSError? {
            print("The request failed. Error: \(error)")
        }

        let paginatedOutput = task.result! 

        for emp in paginatedOutput.items as! [Employees]  {

            self.myVariables.empDict["empid"] =  emp._empid
            self.myVariables.empDict["email"] = emp._email
            self.myVariables.empDict["firstname"] = emp._firstname
            self.myVariables.empDict["lastname"] = emp._lastname
            self.myVariables.empDict["location"] = emp._location
            self.myVariables.empDict["mobile"] = emp._mobile
            self.myVariables.empDict["work"] = emp._work
            self.myVariables.empDict["site"] = emp._site

            self.myVariables.arrayEmployees.append(self.myVariables.empDict)

            //print(self.myVariables.arrayEmployees) // this works

        } // for loop

        self.employeeSearch = self.myVariables.arrayEmployees
        print("printing employeeSearch")
        print(self.employeeSearch) // This works
// self.employee1View.reloadData()
// tried reloading here (above - showing here as commented), but getting error: UITableView.reloadData() must be used from main thread only
        return nil
    } // dynamoDBObjectMapper.scan
// self.employee1View.reloadData()
// Then I tried reload above (showing here as commented), but I get error : Expected ',' separator. If I accept compiler's suggestion, it puts a comma just after curly braces above and that causes more errors at the Line dynamoDBObjectMapper.scan error : Cannot invoke 'continueWith' with an argument list of type '(block: (AWSTask<AWSDynamoDBPaginatedOutput>!) -> Any?, Void)' 
    ) // .continueWith
// end dynamodb call

    // other things in this overload function
    // ..
    }

}

然后，当我运行代码时，我在覆盖表视图中添加了一条打印命令，但它显示的是[[]之类的空白数组。

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

    print("printing employeSearch from numberOfRowsInSection")
    print(employeeSearch) // This returns blank like []
    if isSearching {
        return currentEmployeeSearch.count
    }
    return employeeSearch.count

}

我尝试过多次尝试重新加载表视图，但这也无济于事。

这是具有isSearching变量的搜索功能

func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {

    if searchBar.text == nil || searchBar.text == "" {
        isSearching = false
        view.endEditing(true)
        employee1View.reloadData()
    } else {
        isSearching = true
        employeeSearch = empListDict // getSwiftArrayFromPlist()

        currentEmployeeSearch = employeeSearch.filter {($0["lastname"]?.lowercased().contains(searchText.lowercased())) ?? false}
        employee1View.reloadData()
    }
}

Answer 1

ok尝试在您获取数据后（例如在封存中）重新加载数据。

您必须像这样在主线程中重新加载数据：

 DispatchQueue.main.async {  
self.employee1View.reloadData()
}

Swift 4-DynamoDB数据未显示在TableView中

1 个答案: