B4J Question Combox with lazy loading CVL

[Schakalaka]

Hello, i have create a customlist view thata load data from mysql conneccted directly with jdbc.
I see that it is a bit slow to load results and maybe the problem are the B4XComboBox inside.

I use this sub for load the B4XComboBox

Sub LoadFilterComboBox(ComboBox As B4XComboBox, Tablename As String, Columnname As String,filter As Boolean, filterField As String, filterResult As String)
    Dim lstCombo As List
    lstCombo.Initialize
   
    Dim TablenameID As String = Tablename.Replace("tbl_", "") & "ID"
    Log(TablenameID)
    ' Esegui una query per recuperare i dati dinamicamente da MySQL
    If filter = True Then
        Dim Query As String = "SELECT " & TablenameID.Trim & "," & Columnname.Trim & " FROM " & Tablename.Trim & " WHERE "  & filterField.Trim & " = '" & filterResult.Trim & "' ORDER BY " & Columnname.Trim
       
    Else
       
        Dim Query As String = "SELECT " & TablenameID.Trim & "," & Columnname.trim & " FROM " & Tablename.trim & " ORDER BY " & Columnname.trim
        Log(Query)
    End If
    Log(Query)
    Dim ResultSet As SD_ResultSet = Main.MYSQL.ExecQuery(Query)
    ' Verifica se la query ha successo
    If ResultSet <> Null Then
        ' Svuota gli elementi esistenti della ComboBox
        Log(ResultSet)
        ' Aggiungi i risultati alla ComboBox dinamica
        ComboBox.cmbBox.Items.Clear
        Do While ResultSet.NextRow
            lstCombo.Add(ResultSet.GetString(Columnname)) ' Aggiunge il valore alla ComboBox dinamica
        Loop
   
        ResultSet.Close
   
        ComboBox.SetItems(lstCombo)

    Else
        Log("Query fallita.")
   
    End If

End Sub

this is where i load che combox with lazy loading

Private Sub clvUsrLst_VisibleRangeChanged(FirstIndex As Int, LastIndex As Int)
    Dim ExtraSize As Int = 25 ' Estensione del range visibile

    ' Inizializza la lista Layouts solo una volta
    If Layouts.IsInitialized = False Then Layouts.Initialize
    helper.LoadExtendedComboBox(cmbCompany, "tbl_company", "CompanyName",lstcompany)
    helper.LoadExtendedComboBox(cmbWorkerty, "tbl_worker_types", "WorkerTypeName",lstWorkerty)
    helper.LoadExtendedComboBox(cmbLocation, "tbl_location", "LocationName",lstLocation)
    helper.LoadExtendedComboBox(cmbDepartement, "tbl_department", "DepartmentName", lstDepartement)
   
    ' Scorri gli elementi entro il range visibile + margine
    For i = Max(0, FirstIndex - ExtraSize) To Min(LastIndex + ExtraSize, clvUsrLst.Size - 1)

        'Dim Pnl As B4XView = clvUsrLst.GetPanel(i) ' Pannello corrente
        Panel1 = clvUsrLst.GetPanel(i) ' Pannello corrente
        Dim tdettagli As usrDetails = clvUsrLst.GetValue(i) ' Dati dell'elemento corrente

        If i >= FirstIndex - ExtraSize And i <= LastIndex + ExtraSize Then ' Elemento visibile
            If Panel1.NumberOfViews = 0 Then ' Carica solo se non già visibile
                Dim content As B4XView
                If Layouts.Size > 0 Then
                    ' Riutilizza un layout esistente
                    content = Layouts.Get(0)
                    Layouts.RemoveAt(0)
                Else
                    ' Crea un nuovo layout se nessuno è disponibile
                    content = xui.CreatePanel("")
                End If
                Panel1.AddView(content, 0, 0, Panel1.Width, Panel1.Height)
                Panel1.LoadLayout("clv_SingleUser") ' Carica il layout

                ' Popola i campi
               
                edtname.Text = tdettagli.usrName
                edtSurname.Text = tdettagli.usrSurname
                edtBadge.Text = tdettagli.badge
                edtJDE.Text = tdettagli.usrJDE
               

                If cmbCompany.Size = 0 Then cmbCompany.SetItems(lstcompany)
                If cmbDepartement.Size = 0 Then cmbDepartement.SetItems(lstDepartement)
                If cmbLocation.Size = 0 Then cmbLocation.SetItems(lstLocation)
                If cmbWorkerty.Size = 0 Then cmbWorkerty.SetItems(lstWorkerty)
               
                ' Seleziona gli indici corretti
                cmbCompany.SelectedIndex = lstcompany.IndexOf(tdettagli.usrCompany)
                cmbDepartement.SelectedIndex = lstDepartement.IndexOf(tdettagli.usrDepartment)
                cmbLocation.SelectedIndex = lstLocation.IndexOf(tdettagli.usrLocation)
                cmbWorkerty.SelectedIndex = lstWorkerty.IndexOf(tdettagli.usrWrkType)
               
            End If
        Else ' Elemento non visibile
            If Panel1.NumberOfViews > 0 Then
                Dim content As B4XView = Panel1.GetView(0)
                content.RemoveViewFromParent ' Rimuovi il layout dal pannello
                Layouts.Add(content) ' Aggiungi il layout alla lista per il riutilizzo
                Panel1.RemoveAllViews ' Svuota il pannello
            End If
        End If
    Next

    ' Rimuove il focus dai campi di testo impostando il focus su un componente generico
    clvUsrLst.AsView.RequestFocus
End Sub

There are other ways?
is it possible load faster or better?

 

[Lucas Siqueira]

Before loading the clv, I would make the 4 selects (tbl_company, tbl_worker_types, tbl_location and tbl_department), and store the result in a list (in the sub globals) for each of the 4 selects.

When loading the clv layout, when loading the options into the combobox, you no longer need to make new selects, but rather search for the data from the list.