B4J Question [solved] Test Null?

MarkusR said:

its a bug?
output is
null
null

B4X:

'B4J 7.51
Sub Test2
 
    Dim Params As Map
    Params.Initialize
    'Params.Put("Key","ABC") 'without this row .Get Return something that can Not be Test As null
 
    Dim MyString As String
    MyString = Params.Get("Key")
    Log(MyString)
    'If IsNull(MyString) Then MyString = "123"
    If MyString = Null Or MyString = "" Then MyString = "123"
    Log(MyString)
 
End Sub

Sub IsNull(O As Object) As Boolean
    Return (O=Null)
End Sub

Click to expand...

MyString = Null

MyString = "null"

Sub Test2
 Dim Params As Map
 Dim o As Object
 Params.Initialize
' Params.Put("Key","ABC") 'without this row .Get Return something that can Not be Test As null
 
 Dim MyString As String
 o = Params.Get("Key")
 If o Is Object Then
  MyString = o
 Else
  MyString = "123"
 End If
 Log(MyString)
End Sub

Erel said:

The Null value is converted to "null" string.
The less you work with nulls the better, especially with strings. It is better to write it like this:

B4X:

Dim MyString As String = Params.GetDefault("Key", "")
If MyString = "" Then ...

Click to expand...

MarkusR said:

and a method Params.KeyExists("Key")

Click to expand...

If Map.ContainsKey("Key")