Hi all,
Now that ExternalStorage is the only way to access a shared file in an app that need to be released on Google Play Store, I mixed this:
www.b4x.com
with this:
www.b4x.com
adding these methods to original ExternalStorage class:
File.WriteString - Writes the given text to a new file.
File.ReadString - Reads a file and returns it content as a string.
File.WriteList - Writes all values stored in a list to a file. 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.
File.ReadList - Reads a file and stores each line as an item in a list.
File.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.
File.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.
Note that the class is inline in the project (taken from ExternalStorage b4xlib), if you like it you can put in the b4xlib.
If you do not need to release app on Google Play Store consider this that is a better option:
https://www.b4x.com/android/forum/t...cess-internal-external-storage-sdk-30.130411/
I've attached the example project that works as in the second link but with ExternalStorage.
I even added an useful method to copy files to external storage:
I have 2 questions here, I know that the class store a file with URIs in DirInternal, but how to know these at runtime ?
- If user not already granted a permisson (so we can show a messagebox to explain that need to select a folder, only if no permisson granted and before Storage.SelectDir)
- If permisson already granted, but user removed the Root folder, eg with a file manager.
Please, reply to my questions
and enjoy with this code.
Here a full class code:
Now that ExternalStorage is the only way to access a shared file in an app that need to be released on Google Play Store, I mixed this:
ExternalStorage - Access SD cards and USB sticks
Before we start: External storage means a real sd card or a connected mass storage USB device. This class can also be used to access the secondary storage (File.DirRootExternal). This becomes relevant with newer versions of Android that restrict direct access. It has nothing to do with runtime...
www.b4x.com
Text files
Many applications require access to a persistent storage. The two most common storage types are files and databases. We will cover text files in this tutorial. The predefined Files object has several utility methods for working with text files which are pretty easy to use. Files locations -...
www.b4x.com
adding these methods to original ExternalStorage class:
File.WriteString - Writes the given text to a new file.
File.ReadString - Reads a file and returns it content as a string.
File.WriteList - Writes all values stored in a list to a file. 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.
File.ReadList - Reads a file and stores each line as an item in a list.
File.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.
File.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.
Note that the class is inline in the project (taken from ExternalStorage b4xlib), if you like it you can put in the b4xlib.
If you do not need to release app on Google Play Store consider this that is a better option:
https://www.b4x.com/android/forum/t...cess-internal-external-storage-sdk-30.130411/
I've attached the example project that works as in the second link but with ExternalStorage.
I even added an useful method to copy files to external storage:
B4X:
'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 SubI have 2 questions here, I know that the class store a file with URIs in DirInternal, but how to know these at runtime ?
- If user not already granted a permisson (so we can show a messagebox to explain that need to select a folder, only if no permisson granted and before Storage.SelectDir)
- If permisson already granted, but user removed the Root folder, eg with a file manager.
Please, reply to my questions
and enjoy with this code.
Here a full class code:
B4X:
#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
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