Android Question Issues making Dirs and File

AddManifestText(
<uses-sdk android:minSdkVersion="14" android:targetSdkVersion="26"/>
<supports-screens android:largeScreens="true"
    android:normalScreens="true"
    android:smallScreens="true"
    android:anyDensity="true"/>
<uses-permission
      android:name="android.permission.WRITE_EXTERNAL_STORAGE"
      android:maxSdkVersion="26" />
    )

    If File.ExternalWritable  = False Then
        Msgbox("SD-Karte Error Write !","Warning")
        Log(File.DirDefaultExternal)
        'Return
    End If

/storage/emulated/0/Android/data/my.testapp.de/files

Dim dircalc As String
    If File.ExternalReadable = True Then
        If Not(File.Exists(File.DirDefaultExternal,"/calcul")) Then
            File.MakeDir(File.DirDefaultExternal,"calcul")
        End If
        dircalc= File.DirDefaultExternal&"/calcul"
        Dim idir As Boolean
        idir=File.IsDirectory(File.DirDefaultExternal,"calcul")
        Log("dircalc 1 "&dircalc)
        Log("idir1 = " & idir)
    Else
        If Not(File.Exists(File.DirRootExternal,"/calcul")) Then
            File.MakeDir(File.DirRootExternal,"calcul")
        End If
        dircalc= File.DirRootExternal&"/calcul"
        Dim idir As Boolean
        idir=File.IsDirectory(File.DirRootExternal,"calcul")
        Log("dircalc 2 "&dircalc)
        Log("idir2 = " & idir)
    End If

--------- beginning of main
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
dircalc 1 /storage/emulated/0/Android/data/b4a.example/files/calcul
idir1 = true
** Activity (main) Resume **
** Activity (main) Pause, UserClosed = false **
--------- beginning of system
** Activity (main) Resume **
** Activity (main) Pause, UserClosed = false **