Android Apps Over the 50MB Barrier


Android applications have historically been limited to a maximum size of 50MB. This works for most apps, and smaller is usually better — every megabyte you add makes it harder for your users to download and get started. However, some types of apps, like high-quality 3D interactive games, require more local resources.

So today, we’re expanding the Android app size limit to 4GB.

The size of your APK file will still be limited to 50MB to ensure secure on-device storage, but you can now attach expansion files to your APK.

  • Each app can have two expansion files, each one up to 2GB, in whatever format you choose.
  • Android Market will host the files to save you the hassle and cost of file serving.
  • Users will see the total size of your app and all of the downloads before they install/purchase.

On most newer devices, when users download your app from Android Market, the expansion files will be downloaded automatically, and the refund period won’t start until the expansion files are downloaded. On older devices, your app will download the expansion files the first time it runs, via a downloader library which we’ve provided below.

While you can use the two expansion files any way you wish, we recommend that one serve as the initial download and be rarely if ever updated; the second can be smaller and serve as a “patch carrier,” getting versioned with each major release.

Helpful Resources

In order to make expansion file downloading as easy as possible for developers, we’re providing sample code and libraries in the Android SDK Manager.

  • In the Google Market Licensing package, an updated License Verification Library (LVL). This minor update mostly adds the ability to obtain expansion file details from the licensing server.
  • From the Google Market APK Expansion package, the downloader service example. The library makes it relatively simple to implement a downloader service in your application that follows many of our best practices, including resuming downloads and displaying a progress notification.

Because many developers may not be used to working with one or two large files for all of their secondary content, the example code also includes support for using a Zip file as the secondary file. The Zip example implements a reasonable patching strategy that allows for the main expansion file to “patch” the APK and the patch file to “patch” both the APK and the main expansion file by searching for asset files in all three places, in the order patch->main->APK.

Expansion File Basics

Expansion files have a specific naming convention and are located in a specific place for each app. As expansion files are uploaded to the publisher site, they are assigned a version code based upon the version of the APK that they are associated with. The naming convention and location are as follows:

Location: /Android/obb//
Filename: [main|patch]...obb
Example: /sdcard/Android/obb/com.example.myapp/

Expansion files are stored in shared storage. Unlike APK files, they can be read by any application.

Downloading and Using the Expansion Files

When the primary activity for the app is created, it should check to make sure the expansion files are available. The downloader library provides helper functions (for example the “Helpers” class in the code below) to make this easy.

boolean expansionFilesDelivered() {
    // get filename where main == true and version == 3
    String fileName = Helpers.getExpansionAPKFileName(this, true, 3);
    // does the file exist with FILE_SIZE?
    if (!Helpers.doesFileExist(this, fileName, FILE_SIZE, false)) {
        return false;
    return true;

If the file does not exist, fire up the downloader service with DownloaderClientMarshaller.startDownloadServiceIfRequired(). The downloader will perform an LVL check against the server. This check will deliver the names of the files, file sizes, and the file URLs.

Once that check has been completed, it will begin downloading the files. You don’t have to use our download solution, but you might want to because we:

  • Include a notification UI that provides progress and estimated completion time in layouts customized for ICS and pre-ICS devices
  • Resume large files safely
  • Handle redirection with appropriate limits
  • Run in the background as a service
  • Pause and resume downloads when WiFi is not available

Enjoy! We can’t wait to see what kinds of things developers do with this! For more information about how to use expansion files with your app, read the APK Expansion Files developer guide.

Geo Sitemap Generator’s New Features

The “grand daddy” of geo sitemap generators has recently included some new features. Geo Sitemap Generator, first released by Arjan Snaterse in 2009, has added the ability to generate either a file or a microformatted file of your contact information. In addition to the features in the geo sitemap tool that I reviewed last week, Geo Sitemap Generator supports multiple locations and now provides a preview of the KML file locations on a Map.

The benefits of multiple locations are obvious if you need them. The benefits of the map preview are not so obvious but very real. KML files require a mapping API to generate the lat long info included in the file. Sometimes the information from the API, even from the same map provider, renders the location differently than reality or differently than the public mapping program. It has always been a good idea to check the KML file’s lat-long accuracy by loading it into something like Google Earth to be sure that it pins the locations correctly. Now Geo Sitemap Generator previews the pins on a Map for you when you go to download your files saving you a necessary step.


Examples for Exporting Access table or query to EXCEL Workbook Files Part 4

Create an Access Query and Export multiple “filtered” versions of an Access  Query (based on data in another table) to separate Worksheets within one EXCEL file via TransferSpreadsheet (VBA)

Generic code to create a temporary query, get list of filtering values, and then loop through the list to filter various data and export each filtered query to separate EXCEL files. In this sample code, the employees assigned to each manager are exported to separate worksheets within the same EXCEL file, one worksheet for each manager.

Dim qdf As DAO.QueryDef
Dim dbs As DAO.Database
Dim rstMgr As DAO.Recordset
Dim strSQL As String, strTemp As String, strMgr As String

' Replace PutEXCELFileNameHereWithoutdotxls with actual EXCEL
' filename without the .xls extension
' (for example, MyEXCELFileName, BUT NOT MyEXCELFileName.xls)
Const strFileName As String = "PutEXCELFileNameHereWithoutdotxls"

Const strQName As String = "zExportQuery"

Set dbs = CurrentDb

' Create temporary query that will be used for exporting data;
' we give it a dummy SQL statement initially (this name will
' be changed by the code to conform to each manager's identification)
strTemp = dbs.TableDefs(0).Name
strSQL = "SELECT * FROM [" & strTemp & "] WHERE 1=0;"
Set qdf = dbs.CreateQueryDef(strQName, strSQL)
strTemp = strQName

' *** code to set strSQL needs to be changed to conform to your
' *** database design -- ManagerID and EmployeesTable need to
' *** be changed to your table and field names
' Get list of ManagerID values -- note: replace my generic table and field names
' with the real names of the EmployeesTable table and the ManagerID field
strSQL = "SELECT DISTINCT ManagerID FROM EmployeesTable;"
Set rstMgr = dbs.OpenRecordset(strSQL, dbOpenDynaset, dbReadOnly)

' Now loop through list of ManagerID values and create a query for each ManagerID
' so that the data can be exported -- the code assumes that the actual names
' of the managers are in a lookup table -- again, replace generic names with
' real names of tables and fields
If rstMgr.EOF = False And rstMgr.BOF = False Then
Do While rstMgr.EOF = False

' *** code to set strMgr needs to be changed to conform to your
' *** database design -- ManagerNameField, ManagersTable, and
' *** ManagerID need to be changed to your table and field names
' *** be changed to your table and field names
strMgr = DLookup("ManagerNameField", "ManagersTable", _
"ManagerID = " & rstMgr!ManagerID.Value)

' *** code to set strSQL needs to be changed to conform to your
' *** database design -- ManagerID, EmployeesTable need to
' *** be changed to your table and field names
strSQL = "SELECT * FROM EmployeesTable WHERE " & _
"ManagerID = " & rstMgr!ManagerID.Value & ";"
Set qdf = dbs.QueryDefs(strTemp)
qdf.Name = "q_" & strMgr
strTemp = qdf.Name
qdf.SQL = strSQL
Set qdf = Nothing

' Replace C:\FolderName\ with actual path
DoCmd.TransferSpreadsheet acExport, acSpreadsheetTypeExcel9, _
strTemp, "C:\FolderName\" & strFileName & ".xls"
End If

Set rstMgr = Nothing

dbs.QueryDefs.Delete strTemp
Set dbs = Nothing