Android Code Snippet External Storage Extras

'Copy a file to External Storage.
'Dir:   The current input file directory, eg. File.DirAssets etc.
'Name:   The current input file name
'Parent:   External Storage parent name (Directory where place a file)
'Rename:   Optionally rename the output file. Pass "" to mantain original name.
Public Sub CopyFileToExternalStorage (Dir As String, Name As String, Parent As ExternalFile, Rename As String) As Boolean
    If File.Exists(Dir, Name) = False Then
        Log("File do not exist while copy to External Storage: " & Name)
        Return False
    End If
 
    Dim iStream As InputStream, oStream As OutputStream
    Dim oFile As ExternalFile
 
    If Rename <> "" Then
        oFile = FindFileOrCreate(Parent, Rename)  ' Optionally rename output file, pass "" to Rename argument will mantain original name
    Else
        oFile = FindFileOrCreate(Parent, Name)
    End If
 
    If oFile.IsInitialized Then
        iStream = File.OpenInput(Dir, Name)
        oStream = OpenOutputStream(oFile)
        File.copy2(iStream, oStream)
        iStream.Close
        oStream.Close
        Return True
    Else
        Log("Cannot create file on External Storage: " & Name)
        Return False
    End If
End Sub

#Event: ExternalFolderAvailable
Private Sub Class_Globals
    Private ion As Object
    Private PersistantUri As String
    Public PreviousUriFileName As String = "PersistantUri"
    Private ctxt As JavaObject
    Private mCallback As Object
    Private mEventName As String
    Public Root As ExternalFile
    Type ExternalFile (Name As String, Length As Long, LastModified As Long, IsFolder As Boolean, Native As JavaObject)
End Sub

Public Sub Initialize (Callback As Object, EventName As String)
    mCallback = Callback
    mEventName = EventName
    ctxt.InitializeContext
End Sub

'Lets the user pick a folder.
'Optionally using the previously selected folder.
Public Sub SelectDir (UsePreviouslySelectedIfAvailable As Boolean)
    If UsePreviouslySelectedIfAvailable And File.Exists(File.DirInternal, PreviousUriFileName) Then     ' ORIGINALE
        PersistantUri = File.ReadString(File.DirInternal, PreviousUriFileName)
        Dim list As List = ctxt.RunMethodJO("getContentResolver", Null).RunMethod("getPersistedUriPermissions", Null)
        If list.IsInitialized Then
            For Each uripermission As JavaObject In list
                Dim u As Uri = uripermission.RunMethod("getUri", Null)
                Dim temp As Object = u
                Dim s As String = temp
                If s = PersistantUri And uripermission.RunMethod("isWritePermission", Null) = True Then
                    Log("Can use persistant uri!")
                    SetPickedDir
                    Return
                End If
            Next
        End If
    End If
    Dim i As Intent
    i.Initialize("android.intent.action.OPEN_DOCUMENT_TREE", "")
    i.PutExtra("android.content.extra.SHOW_ADVANCED", True)
    StartActivityForResult(i)
End Sub

'List all files in the given folder.
Public Sub ListFiles (Folder As ExternalFile) As List
    Dim files() As Object = Folder.Native.RunMethod("listFiles", Null)
    Dim res As List
    res.Initialize
    For Each o As Object In files
        Dim f As JavaObject = o
        res.Add(DocumentFileToExternalFile(f))
    Next
    Return res
End Sub
'Finds the file with the given name.
'Returns an uninitialized ExternalFile if not found.
Public Sub FindFile (Parent As ExternalFile, Name As String) As ExternalFile
    Dim f As JavaObject = Parent.Native.RunMethod("findFile", Array(Name))
    Return DocumentFileToExternalFile(f)
End Sub

'Creates a new file.
Public Sub CreateNewFile (Parent As ExternalFile, Name As String) As ExternalFile
    Return DocumentFileToExternalFile(Parent.Native.RunMethod("createFile", Array("", Name)))
End Sub

'Creates a new folder.
Public Sub CreateNewDir (Parent As ExternalFile, Name As String) As ExternalFile
    Return DocumentFileToExternalFile(Parent.Native.RunMethod("createDirectory", Array(Name)))
End Sub

'Deletes the file.
Public Sub DeleteFile (EF As ExternalFile) As Boolean
    If EF.IsInitialized = False Then Return False
    Return EF.Native.RunMethod("delete", Null)
End Sub

'Open an output stream that writes to the file.
Public Sub OpenOutputStream(EF As ExternalFile) As OutputStream
    Return ctxt.RunMethodJO("getContentResolver", Null).RunMethod("openOutputStream", Array(EF.Native.RunMethod("getUri", Null)))
End Sub
'Open an input stream that reads from the file.
Public Sub OpenInputStream(EF As ExternalFile) As InputStream
    Return ctxt.RunMethodJO("getContentResolver", Null).RunMethod("openInputStream", Array(EF.Native.RunMethod("getUri", Null)))
End Sub

'Finds the file with the given name. If not found creates a new file.
Public Sub FindFileOrCreate (Parent As ExternalFile, Name As String) As ExternalFile
    Dim f As ExternalFile = FindFile(Parent, Name)
    If f.IsInitialized = False Then
        Return CreateNewFile(Parent, Name)
    Else
        Return f
    End If
End Sub

'Finds a file or folder with the given name. Creates a new folder if not exists.
Public Sub FindDirOrCreate(Parent As ExternalFile, Name As String) As ExternalFile
    Dim f As ExternalFile = FindFile(Parent, Name)
    If f.IsInitialized = False Then
        Return CreateNewDir(Parent, Name)
    Else
        Return f
    End If
End Sub

#Region Private Subs
Private Sub DocumentFileToExternalFile (DocumentFile As JavaObject) As ExternalFile
    Dim ef As ExternalFile
    If DocumentFile.IsInitialized = False Then
        Return ef
    End If
    ef.Initialize
    ef.Name = DocumentFile.RunMethod("getName", Null)
    ef.Length = DocumentFile.RunMethod("length", Null)
    ef.IsFolder = DocumentFile.RunMethod("isDirectory", Null)
    ef.Native = DocumentFile
    ef.LastModified = DocumentFile.RunMethod("lastModified", Null)
    Return ef
End Sub

Private Sub SetPickedDir
    Root = DocumentFileToExternalFile(GetPickedDir(PersistantUri))
    CallSubDelayed(mCallback, mEventName & "_ExternalFolderAvailable")
End Sub

Private Sub ion_Event (MethodName As String, Args() As Object) As Object
    If -1 = Args(0) Then 'resultCode = RESULT_OK
        Dim i As Intent = Args(1)
        Dim jo As JavaObject = i
        Dim treeUri As Uri = jo.RunMethod("getData", Null)
        Dim takeFlags As Int = Bit.And(i.Flags, 3)
        ctxt.RunMethodJO("getContentResolver", Null).RunMethod("takePersistableUriPermission", Array(treeUri, takeFlags))
        Dim temp As Object = treeUri
        PersistantUri = temp
        File.WriteString(File.DirInternal, PreviousUriFileName, PersistantUri)
        Log(PersistantUri)
        SetPickedDir
    End If
    Return Null
End Sub

Private Sub GetPickedDir (uri As String) As JavaObject
    Dim DocumentFileStatic As JavaObject
    Dim treeUri As Uri
    treeUri.Parse(uri)
    Dim PickedDir As JavaObject = DocumentFileStatic.InitializeStatic("android.support.v4.provider.DocumentFile").RunMethod("fromTreeUri", Array(ctxt, treeUri))
    Return PickedDir
End Sub

Private Sub StartActivityForResult(i As Intent)
    Dim jo As JavaObject = GetBA
    ion = jo.CreateEvent("anywheresoftware.b4a.IOnActivityResult", "ion", Null)
    jo.RunMethod("startActivityForResult", Array As Object(ion, i))
End Sub

Private Sub GetBA As Object
    Dim jo As JavaObject = Me
    Return jo.RunMethod("getBA", Null)
End Sub
#End Region

'-------------------- MY ADDONS TO ORIGINAL CLASS ----------------------

'    External Storage text file addons.
'
'    Storage.ReadString - Reads a file and returns it content as a string. (OK)
'    Storage.WriteString - Writes the given text to a new file. (OK)
'
'    Storage.ReadList - Reads a file and stores each line as an item in a list.  (OK)
'    Storage.WriteList - Writes all values stored in a list to a file. (OK)
'                     All values are converted to string type if required.
'                          Each value will be stored in its own line.
'                     Note that if a value contains the new line character it will saved over more than one line and when you read it,
'                          it will be read as multiple items.
'
'  Storage.ReadMap - Reads a properties file and returns its key/value pairs as a map object. Note that the order of entries returned might be different than the original order.
'    Storage.WriteMap - Takes a map object which holds pairs of key and value elements and stores it in a text file.
'                    The file format is known as Java Properties file: .properties - Wikipedia, the free encyclopedia
'                  The file format is not too important unless the file is supposed to be edited manually.
'                  This format makes it easy to edit it manually.
'                  One common usage of File.WriteMap is to save a map of "settings" to a file.

'Reads the file and returns its content as a string.
'Example:<code>
'Dim text As String = Storage.ReadString(Storage.Root, "myfile.txt")</code>
Public Sub ReadString (Parent As ExternalFile, Name As String) As String
    If Parent.IsInitialized Then
        Parent = FindFile(Parent, Name)  'FindFileOrCreate(Parent, Name)
        If Parent.IsInitialized Then
            Dim iStream As InputStream = OpenInputStream(Parent)
            Dim b() As Byte = Bit.InputStreamToBytes(iStream)
            Return BytesToString(b, 0, b.Length, "UTF-8")
        Else
            LogColor("CANNOT READ STRING FROM FILE", Colors.Red)
            Return ""
        End If
    Else
        LogColor("WRONG FOLDER WHILE READ STRING FROM FILE", Colors.Red)
        Return ""
    End If
End Sub

'Writes the given text to an existing or new file.
'Example:<code>
'Storage.WriteString(Storage.Root, "myfile.txt", "Some text here")</code>
Public Sub WriteString (Parent As ExternalFile, Name As String, Text As String)
    If Parent.IsInitialized Then
        Parent = FindFileOrCreate(Parent, Name)
        If Parent.IsInitialized Then
            Dim iStream As InputStream
            Dim oStream As OutputStream
            Dim b() As Byte = Text.GetBytes("UTF8")
            iStream.InitializeFromBytesArray(b, 0, b.Length)
            oStream = OpenOutputStream(Parent)
            File.Copy2(iStream, oStream)
        Else
            LogColor("CANNOT WRITE STRING TO FILE", Colors.Red)
        End If
    Else
        LogColor("WRONG FOLDER WHILE WRITE STRING TO FILE", Colors.Red)
    End If
End Sub

'Reads the entire file and returns a List with all lines (as strings).
'Example:<code>
'Dim List1 As List = Storage.ReadList(Storage.Root, "mylist.txt")  ' Use FindDirOrCreate to point another directory
'For i = 0 to List1.Size - 1
'   Log(List1.Get(i))
'Next </code>
Public Sub ReadList (Parent As ExternalFile, Name As String) As List
    If Parent.IsInitialized Then
        Parent = FindFile(Parent, Name)  ' FindFileOrCreate(Parent, Name)
        If Parent.IsInitialized Then
            Dim iStream As InputStream = OpenInputStream(Parent)
            Dim b() As Byte = Bit.InputStreamToBytes(iStream)
            Dim s As String = BytesToString(b, 0, b.Length, "UTF-8")
            Dim components() As String = Regex.Split(CRLF, s) ' Split lines
            Dim lineList As List
            lineList.Initialize2(components)
            Return lineList
        Else
            LogColor("CANNOT READ LIST FROM FILE", Colors.Red)
            Return Null
        End If
    Else
        LogColor("WRONG FOLDER WHILE READ LIST FROM FILE", Colors.Red)
        Return Null
    End If
End Sub

'Writes each item in the list as a single line.
'Note that a value containing CRLF will be saved as two lines (which will return two item when read with ReadList).
'All values will be converted to strings.
'Example:<code>
'Storage.WriteList(Storage.Root, "mylist.txt", List1)  ' Use FindDirOrCreate to point another directory</code>
Public Sub WriteList (Parent As ExternalFile, Name As String, List As List)
    If Parent.IsInitialized Then
        Parent = FindFileOrCreate(Parent, Name)
        If Parent.IsInitialized Then
            Dim sb As StringBuilder
            sb.Initialize
            For Each line As String In List
                sb.Append(line).Append(CRLF)
            Next
 
            Dim iStream As InputStream
            Dim oStream As OutputStream
            Dim b() As Byte = sb.ToString.GetBytes("UTF8")
            iStream.InitializeFromBytesArray(b, 0, b.Length)
            oStream = OpenOutputStream(Parent)
            File.Copy2(iStream, oStream)
        Else
            LogColor("CANNOT WRITE LIST TO FILE", Colors.Red)
        End If
    Else
        LogColor("WRONG FOLDER WHILE WRITE LIST TO FILE", Colors.Red)
    End If
End Sub

'Reads the file and parses each line as a key-value pair (of strings).
'See this link for more information about the actual format: <link>Properties format|http://en.wikipedia.org/wiki/.properties</link>.
'You can use Storage.WriteMap to write a map to a file.
'Note that the order of items in the map may not be the same as the order in the file.
Public Sub ReadMap (Parent As ExternalFile, Name As String) As Map
    If Parent.IsInitialized Then
        Parent = FindFile(Parent, Name)  ' FindFileOrCreate(Parent, Name)
        If Parent.IsInitialized Then
            Dim iStream As InputStream = OpenInputStream(Parent)
            Dim b() As Byte = Bit.InputStreamToBytes(iStream)
            Dim str As String = BytesToString(b, 0, b.Length, "UTF-8")
            Dim components() As String = Regex.Split(CRLF, str) ' Split lines
 
            Dim lineMap As Map
            lineMap.Initialize
            For i = 0 To components.Length-1
                Dim s As String = components(i)
                Dim keyval() As String = Regex.Split("=", s) ' Split key-val
                If keyval.Length = 2 Then
                    lineMap.Put(keyval(0), keyval(1))
                Else
                    LogColor("CANNOT EVALUTATE KEY-VALUE PAIRS WHILE READ MAP FROM FILE: " & Parent.Name, Colors.Red)
                End If
            Next
            Return lineMap
        Else
            LogColor("CANNOT READ MAP FROM FILE", Colors.Red)
            Return Null
        End If
    Else
        LogColor("WRONG FOLDER WHILE READ MAP FROM FILE", Colors.Red)
        Return Null
    End If
End Sub

'Uses existing file or creates a new file and writes the given map. Each key value pair is written as a single line.
'All values are converted to strings.
'See this link for more information about the actual format: <link>Properties format|http://en.wikipedia.org/wiki/.properties</link>.
'You can use Storage.ReadMap to read this file.
Public Sub WriteMap (Parent As ExternalFile, Name As String, Map As Map)
    If Parent.IsInitialized Then
        Parent = FindFileOrCreate(Parent, Name)
        If Parent.IsInitialized Then
            Dim sb As StringBuilder
            sb.Initialize
            For Each Key As String In Map.Keys
                sb.Append(Key).Append("=").Append(Map.Get(Key)).Append(CRLF)
            Next
            Dim iStream As InputStream
            Dim oStream As OutputStream
            Dim b() As Byte = sb.ToString.GetBytes("UTF8")
            iStream.InitializeFromBytesArray(b, 0, b.Length)
            oStream = OpenOutputStream(Parent)
            File.Copy2(iStream, oStream)
        Else
            LogColor("CANNOT WRITE MAP TO FILE", Colors.Red)
        End If
    Else
        LogColor("WRONG FOLDER WHILE WRITE MAP TO FILE", Colors.Red)
    End If
End Sub

'Copy a file to External Storage.
'Dir:   The current input file directory, eg. File.DirAssets etc.
'Name:   The current input file name
'Parent:   External Storage parent name (Directory where place a file)
'Rename:   Optionally rename the output file. Pass "" to mantain original name.
Public Sub CopyFileToExternalStorage (Dir As String, Name As String, Parent As ExternalFile, Rename As String) As Boolean
    If File.Exists(Dir, Name) = False Then
        Log("File do not exist on DirAssets while copy to External Storage: " & Name)
        Return False
    End If
 
    Dim iStream As InputStream, oStream As OutputStream
    Dim oFile As ExternalFile
 
    If Rename <> "" Then
        oFile = FindFileOrCreate(Parent, Rename)  ' Optionally rename output file, pass "" to Rename argument will mantain original name
    Else
        oFile = FindFileOrCreate(Parent, Name)
    End If
 
    If oFile.IsInitialized = True Then
        iStream = File.OpenInput(Dir, Name)
        oStream = OpenOutputStream(oFile)
        File.copy2(iStream, oStream)
        iStream.Close
        oStream.Close
        Return True
    Else
        Log("Cannot create file on External Storage: " & Name)
        Return False
    End If
End Sub

'Need check. Probably call it FileExists, it use FindFile(Parent, Name) and I'm not sure if it is good for folders.
Public Sub Exists (Parent As ExternalFile, Name As String) As Boolean
    Dim ef As ExternalFile = FindFile(Parent, Name)
'    Log("ExternalStorage Exists: [" & Parent.Name & "/" & Name & "]     IsInitialized: " & tmp.IsInitialized)
    Return ef.IsInitialized
End Sub

'Create a folder
Public Sub MakeDir (Parent As ExternalFile, Name As String) As ExternalFile
    Log("MakeDir: [" & Parent.Name & "/" & Name & "]")
    Return CreateNewDir(Parent, Name)
End Sub

'Check if permission is already granted.
Public Sub HasPermission As Boolean  ' <<<<<< We need to check here if user removed root folder
    Return File.Exists(File.DirInternal, PreviousUriFileName) And File.ReadString(File.DirInternal, PreviousUriFileName).Length > 0
End Sub

'Public Sub IsStorageFolderSelected As Boolean
'    PersistantUri = File.ReadString(File.DirInternal, PreviousUriFileName)
'    If PersistantUri.Length > 0 Then
'        Root = DocumentFileToExternalFile(GetPickedDir(PersistantUri))
'        Log("Root.Length=" & Root.Length)
'    End If
'    Return File.Exists(File.DirInternal, PreviousUriFileName) And (Root.Length > 0)
'End Sub