Android Example Automatic adjustment of system date and time through GPS (root only)

Please see:

GPS tutorial
Toggle Library
Toggle on/off GPS in any Android version
Set phone clock from GPS

Advantages:
- System date and time are updated periodically.
- Without paying a data service.
- You do not need internet access.
- Works in offline mode (airplane mode) to save energy.

Disadvantages:
- Need hardware GPS.
- Need root.

In this code (attached):
- On/Off GPS
- Shell command line [root]
- Get locale GPS DateTime
- Set system DateTime
- Start At Boot

Tested with [Android SDK 19]:
- Android 6 (Only to get GPS data - don't have root)
- Android 2.3.6 (All functions works - with root)

GPSservice Service Module:

#Region  Service Attributes
    #StartAtBoot: False
#End Region

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
   Private gps As GPS
   Private timer1 As Timer
   Dim NewTime As String
   Dim lNewTime As Long
   Dim lNewTime2 As Long
   Dim setEnable As Boolean = True
   Dim setNow As Boolean = False

End Sub

Sub Service_Create

   timer1.Initialize("timer1", 30000)
   timer1.Enabled = True
  
   gps.Initialize("gps")
   gps.Start(0, 0)
End Sub

Sub Service_Start (StartingIntent As Intent)

End Sub

Sub Service_Destroy

End Sub

Sub GPSenable(enableValue As Boolean)
    If enableValue Then
        gps.Start(0, 0)
    Else
        gps.Stop
    End If
End Sub

Sub gps_NMEA (TimeStamp As Long, Sentence As String)
   'Log($"$DateTime{TimeStamp}"$)
   'Log(Sentence)
End Sub

Sub GPS_LocationChanged (Location1 As Location)

    lNewTime = Location1.Time
   
    'Log("Location Time: " & lNewTime)
    NewTime = lNewTime
    NewTime = (NewTime.substring2(0,10))

    If setNow And setEnable Then
    'If ((setNow = True) And (setEnable = True)) Then
        shellCmd("date " & NewTime)
        'Log("Set date: " & lNewTime)
        lNewTime2 = lNewTime
        setNow = False
        'ToastMessageShow("Set Date & Time", False)
    End If
   
End Sub

Sub timer1_tick()
    setNow = True
End Sub

Sub updateTextMain()
    CallSubDelayed3(Main, "updateText", lNewTime, lNewTime2)
End Sub

Sub enableAutoSet(setEnable1 As Boolean)
    setEnable = setEnable1
End Sub

Sub shellCmd(Command_in As String) As String
    'Dim Result As Int
    Dim Command, Runner As String
    Dim StdOut, StdErr As StringBuilder
    Dim Ph As Phone
       
    Runner = File.Combine(File.DirInternalCache, "runner")
    Command = File.Combine(File.DirInternalCache, "command")

    File.WriteString(File.DirInternalCache, "runner", "su < " & Command)
    File.WriteString(File.DirInternalCache, "command", Command_in & CRLF & "exit") 'Any commands via crlf, and exit at end
    StdOut.Initialize
    StdErr.Initialize

    'Result = Ph.Shell("sh", Array As String(Runner), StdOut, StdErr)
    Ph.Shell("sh", Array As String(Runner), StdOut, StdErr)

    Return StdOut.tostring
End Sub

Main Activity Module:

#Region  Project Attributes
    #ApplicationLabel: GPS DataTime
    #VersionCode: 1
    #VersionName:
    'SupportedOrientations possible values: unspecified, landscape or portrait.
    #SupportedOrientations: portrait
    #CanInstallToExternalStorage: False
#End Region

#Region  Activity Attributes
    #FullScreen: False
    #IncludeTitle: True
#End Region

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Private timer1 As Timer
    Dim TGL As Toggle
    Dim GPStoggle1 As GpsToggle
End Sub

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    'These variables can only be accessed from this module.

    Private ToggleButton1 As ToggleButton
    Private ToggleButton2 As ToggleButton
    Private EditText1 As EditText
    Private EditText2 As EditText
    Private EditText3 As EditText
   
    Private lastData As Long = 0
    Private Label1 As Label
    Private Label2 As Label
    Private Label3 As Label
    Private Label4 As Label
End Sub

Sub Activity_Create(FirstTime As Boolean)
    'Do not forget to load the layout file created with the visual designer. For example:
    Activity.LoadLayout("Layout1")
    StartService(GPSservice)
    timer1.Initialize("timer1", 100)
    timer1.Enabled = True
    Label1.Text = "Format: yyyy/MM/dd HH:mm:ss"
    TGL.Initialize()
    GPStoggle1.turnGpsOn
End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub

Sub timer1_tick()
    Dim lastDataCalc As Long
    Dim lastDataCalcInt As Int
    lastDataCalc = (DateTime.Now - lastData)
    lastDataCalcInt = lastDataCalc / 1000
   
    CallSubDelayed(GPSservice, "updateTextMain")
   
    EditText1.Text = DateTime.Date(DateTime.Now) & " " & DateTime.Time(DateTime.Now)
   
    EditText3.Text = lastDataCalcInt & " seconds"
End Sub

Sub updateText(inData As Long, inData2 As Long)
    DateTime.DateFormat = "yyyy/MM/dd"
    'DateTime.TimeFormat = "HH:mm:ss"  ' default
    lastData = inData2
    EditText2.Text = DateTime.Date(inData) & " " & DateTime.Time(inData)
End Sub

Sub ToggleButton1_CheckedChange(Checked As Boolean)
    CallSubDelayed2(GPSservice, "GPSenable", Checked)
    ToggleButton2.Enabled = Checked
   
    If ((Checked And TGL.GPS = False) Or (Checked = False And TGL.GPS)) Then
        TGL.ToggleGPS
    End If
   
    If Checked Then
        GPStoggle1.turnGpsOn
    Else
        GPStoggle1.turnGpsOff
    End If
   
End Sub

Sub ToggleButton2_CheckedChange(Checked As Boolean)
    CallSubDelayed2(GPSservice, "enableAutoSet", Checked)
End Sub