iOS Question Use B4XComboBox and IsInitialized

angel_ · Jul 22, 2020

In a project I have something similar to this, it's just an example, if it's not loaded the B4XComboBox gives error (in B4A it works) I have to use Try EndTry instead of IsInitialized

B4X:

    Dim Lista As List = Array("aa", "bb", "cc")
    Dim Seleccion As String
    
    #If B4a
        Seleccion = B4XComboBox1.SelectedItem
    #Else If B4i
        '1st option
        If B4XComboBox1.IsInitialized Then
            Seleccion = B4XComboBox1.SelectedItem
        Else
            Seleccion = ""
        End If
        
        '2nd option
'        Try
'            Seleccion = B4XComboBox1.SelectedItem
'        Catch
'            Seleccion = ""
'            Log(LastException)
'        End Try
    #End If
    
    B4XComboBox1.SetItems(Lista)
    B4XComboBox1.SelectedIndex = Max(B4XComboBox1.IndexOf(Seleccion), 0)

Erel · Jul 22, 2020

No need to check. It will always be initialized after the layout was loaded.

I don't understand what you are trying to do. You cannot get the selected item before you set the items.

angel_ · Jul 22, 2020

Erel said:
I don't understand what you are trying to do. You cannot get the selected item before you set the items.

Let's see if that's how it is understood, if not, I'll upload an example. The question is if I have to use Try EndTry or is another option better

B4X:

Private Sub B4XPage_Created (Root1 As B4XView)
    Root = Root1
    Root.LoadLayout("Page2")
    
    kvs.Initialize(xui.DefaultFolder, "kvs.dat")
    
    B4XSwitch1.Value = kvs.GetDefault("B4XSwitch1", True)
    B4XSwitch2.Value = Not(B4XSwitch1.Value)
    
    LoadCombo
    
    B4XComboBox1.SelectedIndex = kvs.GetDefault("B4XComboBox1", B4XComboBox1.SelectedIndex)
End Sub

Sub B4XPage_Disappear
    kvs.Put("B4XSwitch1", B4XSwitch1.Value)
    kvs.Put("B4XComboBox1", B4XComboBox1.SelectedIndex)
End Sub

Sub B4XSwitch_ValueChanged (Value As Boolean)
    LoadCombo
End Sub

Sub LoadCombo
    #If B4a
        Before = B4XComboBox1.SelectedItem
    #Else If B4i
    '1st option
    If B4XComboBox1.IsInitialized Then
        Before = B4XComboBox1.SelectedItem
    Else
        Before = ""
    End If
        
    '2nd option
'    Try
'        Before = B4XComboBox1.SelectedItem
'    Catch
'        Before = ""
'        Log(LastException)
'    End Try
    #End If
    
    Lista.Initialize
    
    If B4XSwitch1.Value Then
        Lista = Lista1
    Else
        Lista = Lista2
    End If

    B4XComboBox1.SetItems(Lista)
    B4XComboBox1.SelectedIndex = Max(B4XComboBox1.IndexOf(Before), 0)
End Sub

Erel · Jul 23, 2020

The solution with Try / Catch is a bad solution.

You also don't need the platform specific code.

I'm not sure what you are trying to do, so cannot say more.

angel_ · Jul 23, 2020

Sorry, maybe I'll explain better with the attachment

Erel · Jul 23, 2020

You need to set the items before you do anything else.

You can even set an empty array:

B4X:

cmb.SetItems(Array())

iOS Question Use B4XComboBox and IsInitialized

angel_

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Erel

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angel_

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Erel

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iOS Question Use B4XComboBox and IsInitialized

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