Android Question Append text with ExternalStorage class

[Wosl]

Dear All,

I'm using ExternalStorage https://www.b4x.com/android/forum/threads/externalstorage-access-sd-cards-and-usb-sticks.90238/ to store text data on my external device (SD card). This works as expected, when a new file is created and the content is written to it. But how can I append text to an existing file?

Wosl

Here is my sample code:

#Region  Project Attributes
    #ApplicationLabel: SDCard
    #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
#AdditionalJar: androidx.legacy:legacy-support-core-utils
Sub Process_Globals
    Public Storage As ExternalStorage
End Sub
Sub Globals
End Sub
Sub Activity_Create(FirstTime As Boolean)
    '  Create a file on external device in preselected folder
    '  Output text to it
    '  Second Step: append additional text
    Private cCSV As String, cFileDir As String = "TestDir", cFileCSV As String = "Test.csv"
    Private cStoragePath As ExternalFile, extFile As ExternalFile, storedFile As ExternalFile
    Private DestinationFile As ExternalFile
    Private outputstream As OutputStream, inputstream As InputStream
    
    '  Storage initialization for external device
    Storage.Initialize (Me, "Storage")
    
    '  Wait until external system is available and call user prompt if not
    Storage.SelectDir(True)
    Wait For Storage_ExternalFolderAvailable
    
    '  Output file to external storage
    cStoragePath = Storage.Root
    extFile = Storage.FindDirOrCreate(cStoragePath, cFileDir)
    
    ' Find a file in selected folder and delete it if existing
    storedFile = Storage.FindFile(extFile,cFileCSV)
    If storedFile.IsInitialized = True Then
        Storage.DeleteFile(storedFile)
    End If

    '  Copy a string to inputstream
    cCSV = "Header1;Header2" & CRLF & "Value11;Value12" & CRLF & "Value21;Value22"
    inputstream = StringToInputStream (cCSV)
    
    '  Allocate a new file on external device
    DestinationFile = Storage.CreateNewFile(extFile,cFileCSV)
    outputstream    = Storage.OpenOutputStream(DestinationFile)
    
    '  Copy new file to external device
    File.Copy2(inputstream,outputstream)

    '  Close streams
    outputstream.Close
    inputstream.Close
    Log ("File '" & cFileCSV & "' created in folder '" & cFileDir & "'")
    Log ("Content of 'cCSV' written to File '" & cFileCSV & "'")
    
    '  Second step: add text to file
    cCSV = "Value31;Value32"
    '---------->  append data to existing file ????
    '  Close app
    Activity.Finish
    ExitApplication
End Sub
Sub StringToInputStream (s As String) As InputStream
    '  Copy string to inputstream
    Dim In As InputStream
    Dim data() As Byte = s.GetBytes("UTF8")
    In.InitializeFromBytesArray(data, 0, data.Length)
    Return In
End Sub

 

[Erel]

Untested sub:

Public Sub OpenOutputStreamAppend(EF As ExternalFile) As OutputStream
    Dim ctxt As JavaObject
    ctxt.InitializeContext
    Return ctxt.RunMethodJO("getContentResolver", Null).RunMethod("openOutputStream", Array(EF.Native.RunMethod("getUri", Null), "wa"))
End Sub

You can put with your code.