Android Code Snippet Sharing the goodness: Form Input Validation

Hi

As my b4a apps at times deal with form input validation, I needed some subs that I could just run in my forms e.g. checking if a textbox is blank, confirming passwords etc, so I came up with this...

For the messagebox functions please refer to this post https://www.b4x.com/android/forum/threads/sharing-the-goodness-msgbox-things.58894/

1. Check if two textboxes values are the same, if same don't continue.

' verify input of two textboxes
Sub IsSame(valueToCheck As String, valueToCheck1 As String, valueToCheckTitle As String) As Boolean
    valueToCheck = valueToCheck.Trim
    valueToCheck1 = valueToCheck1.Trim
    If valueToCheck = valueToCheck1 Then
        Dim msg As String
        msg = "The " & valueToCheckTitle & " must not be " & valueToCheck1 & ", please correct this!"
        Error("Input", msg)
        Return True
    Else
        Return False
    End If
End Sub

Usage:

If IsSame(txt1.text,txt2.text, "Username") = True Then Return

2. Check if textbox value is blank and don't continue if blank

Sub IsBlank(valueToCheck As String, title As String) As Boolean
    valueToCheck = valueToCheck.Trim
    If valueToCheck.Length = 0 Then
        Dim msg As String
        msg = "The " & title & " cannot be blank, please enter the " & title.ToLowerCase  & "!"
        Error(title,msg)
        Return True
    Else
        Return False
    End If
End Sub

Usage:

If IsBlank(txt1.text, "Email") = True The  Return

3. Check if two text boxes are not the same, if true, don't continue.

Sub DoNotMatch(valueToCheck As String, valueToCheck1 As String, valueToCheckTitle As String, valueToCheck1Title As String) As Boolean
    valueToCheck = valueToCheck.Trim
    valueToCheck1 = valueToCheck1.Trim
    If valueToCheck <> valueToCheck1 Then
        Dim msg As String
        msg = "The " & valueToCheckTitle & " and the " & valueToCheck1Title & " do not match, please correct this!"
        Error("Input", msg)
        Return True
    Else
        Return False
    End If
End Sub

Usage:

If DoNotMatch(txt1.text,txt2.text,"Password", "Confirm Password") = True then Return

4. Check if text box value is a valid email, if not don't continue.

Sub IsEmail(EmailAddress As String) As Boolean
    If EmailAddress.Length = 0 Then Return True
    Dim MatchEmail As Matcher = Regex.Matcher("^(?i)[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])$", EmailAddress)
    If MatchEmail.Find = True Then
        Return True
    Else
        Return False
    End If
End Sub

Sub IsNotValidEmail(valueToCheck As String, title As String) As Boolean
    valueToCheck = valueToCheck.Trim
    If IsEmail(valueToCheck)= False Then
        Dim msg As String
        msg = "The " & title & " is not a valid email address, please check and correct the " & title.ToLowerCase  & "!"
        Error(title,msg)
        Return True
    Else
        Return False
    End If
End Sub

Usage:

If IsNotValidEmail(txt1.text,"Email Address") = True Then Return