Android Question Chrono Pause, Stop, Reset with DateUtils

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Private xui As XUI
    Private T_clock As Timer
End Sub

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    Private clk_BtPause As Boolean = False
    Private myTimeZone As Int
    Private H_Start, H_End As String
    Private lblDiff As Label
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("Layout")
    
    'Defined the TimeZone and general date time format
    Dim s, d As String
    Dim l As Long
    s = DateTime.DateFormat
    DateTime.DateFormat = "MM-dd-yyyy HH:mm:ss"
    l = DateTime.Now
    d = DateTime.Date(l) & " GMT"
    DateTime.DateFormat = "MM-dd-yyyy HH:mm:ss z"
    myTimeZone = -Round((l - DateTime.DateParse(d))/3600000)
    DateTime.DateFormat = s
    DateTime.SetTimeZone(myTimeZone)
    DateTime.DateFormat = "EEEE dd MMMM" 'Date format
    DateTime.TimeFormat="HH:mm:ss" 'Time format
    
    'default chrono label
    lblDiff.Text = "00:00:00"

End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub

Private Sub btStart_Click
    
    If clk_BtPause = True Then 'Relaunch after clicking the pause button
    
        'Convert string -pause time- to long. The chrono time when we click on the pause button ex: 00:01:23
        Dim dfPause As String = DateTime.DateFormat
        Dim pause As Long
        DateTime.DateFormat = "HH:mm:ss"
        pause = DateTime.DateParse(lblDiff.Text)
        DateTime.DateFormat = dfPause
        
        'Convert string -current time- to long. The system time when we click on the pause button
        Dim dfCurrTime As String = DateTime.DateFormat
        Dim currTime As Long
        DateTime.DateFormat = "HH:mm:ss"
        currTime = DateTime.DateParse(DateTime.time(DateTime.Now))
        DateTime.DateFormat = dfCurrTime
                
        'We restart at the current system time minus the break time.
        Dim myStartTime As Long
        DateTime.SetTimeZone(0)
        myStartTime = currTime - pause
        DateTime.DateFormat="HH:mm:ss"
        
        'New start time - the time is 2 times in the restart string. I do not know why
        Dim restart As String = DateUtils.TicksToString(myStartTime)
        Dim mystart() As String
        mystart = Regex.Split(" ",restart)
        H_Start = mystart(0)
        
        'End time is now
        DateTime.SetTimeZone(myTimeZone)
        H_End = DateTime.time(DateTime.Now)
        T_clock.Enabled = True
        
        clk_BtPause = False
        
    Else
        'Start the chrono
        If T_clock.Enabled = True Then
            xui.MsgboxAsync("Stop the chrono before starting a new one","oups!")
            Return
        Else
            'The chrono starts with the system time
            H_Start = DateTime.time(DateTime.Now)
            T_clock.Initialize("myTemps",1000)
            T_clock.Enabled = True
            
        End If
        
    End If

End Sub

Sub myTemps_Tick
    
    'H_Start = The time at which we started the chrono. This time is fixed (btStart_Click)
    'H_End = The time is current time. This time changes seconds after seconds
    H_End = DateTime.time(DateTime.Now)
    
    'Calculate and show the difference between the two times
    myDiff (H_Start, H_End)

End Sub

Sub myDiff (StartH As String, EndH As String)
    
    Dim PerDiff As Period
    Dim HS() As String
    Dim HE() As String
    
    'Split hh:mm:ss
    HS = Regex.Split("\:",StartH)
    HE = Regex.Split("\:",EndH)
    HS = Regex.Split("\:",StartH)
    HE = Regex.Split("\:",EndH)
    
    'Years, Months, Days, is not use
    Dim TimeA As Long = DateUtils.SetDateAndTime(2020, 10, 10, HS(0), HS(1), HS(2))
    Dim TimeB As Long = DateUtils.SetDateAndTime(2020, 10, 10, HE(0), HE(1), HE(2))
    
    PerDiff = DateUtils.PeriodBetween(TimeA, TimeB)
    
    'To have two digits
    Dim h, m, s As String
    h = PerDiff.Hours
    m = PerDiff.Minutes
    s = PerDiff.Seconds
    If h.Length = 1 Then
        h = "0"&PerDiff.Hours
    End If
    If m.Length = 1 Then
        m = "0"&PerDiff.Minutes
    End If
    If s.Length = 1 Then
        s = "0"&PerDiff.Seconds
    End If
    
    'Show the chrono
    lblDiff.Text = h & ":" & m & ":" & s

End Sub

Private Sub btPause_Click
    clk_BtPause = True 'Check if the pause button has been clicked
    T_clock.Enabled = False
End Sub

Private Sub btStop_Click
    T_clock.Enabled = False
End Sub

Private Sub btReset_Click
    If clk_BtPause = True Then
        xui.MsgboxAsync("The chrono is paused","oups!")
        Return
    Else
        If T_clock.Enabled = True Then
            xui.MsgboxAsync("Stop the chrono before reseting","oups!")
            Return
        Else
            T_clock.Enabled = False
            lblDiff.Text = "00:00:00"
        End If
    End If
    T_clock.Enabled = False
    lblDiff.Text = "00:00:00"
End Sub