Directory structure for GMA apps

Platform-specific rules need to be considered when deploying on Android™ devices (GMA).

The application sandbox

On Android devices, applications are deployed in an application sandbox. The application can access and store data outside of its space, but then the data is also accessible by the other applications.

Directory structure for a GMA application

Inside its application sandbox, an Android app uses the following directory structure:

appdir/
|-- main.42m                            --
|-- *.42m                                 |
|-- *.42f                                 |
|-- fglprofile                            |
|   ...                                   |
|-- defaults/*.42s                        |
|-- de/                                   | Program files
|   |-- *.42s                             |
|-- fr/                                   |
|   |-- *.42s                             |
|-- zh/                                   |
|   |-- *.42s                             |
|   ...                                   |
|-- ... other resource files/dirs ...     |
|   ...                                   |
|-- webcomponents                         |
|   |-- component-type                    |
|       |-- component-type.html           |
|       |-- other-web-comp-resource       |
|   ...                                  --

|-- appdata/
    |-- ... writable app files ...
  
tmpdir/
|-- ... temporary files ...

Program files directory (`appdir`)

Application program files (.42m, .42f, and so on) need to be deployed in the appdir application base directory.

The program files directory can be found in programs with the base.Application.getProgramDir method.

Important:

On Android, the program files directory returned by the base.Application.getProgramDir() method is the same directory as the default working directory, returned by os.Path.pwd().

The FGLAPPDIR environment variable is automatically set to the appdir directory.

Program name (MAIN)

When deploying on mobile devices, the name of the program file must be main.42m or main.42r.

When using the command-line app build scripts, the name of the program file must be main.42?. When using Genero Studio, the packaging script takes care of renaming this file, if you have not named it main.

As with other program files, the "MAIN" module must be located under the appdir application program directory.

Working directory

On Android devices, the default current working directory is the appdir directory, and can be used for writable files.

The current working directory can be found in programs with the os.Path.pwd method.

Files that need to be writable (such as SQLite database files) can be created directly under the appdir directory. However, to better organize application files, create sub-directories such as appdir/appdata, keeping original files directly under the appdir directory. For example, create the application database under os.Path.pwd() || "/database".

Temporary directory (`tmpdir`)

A temporary directory is available for the application.

In order to find the temporary directory for the app, use the standard.feInfo front call, with the "dataDirectory" parameter.

To create a temporary file name, use the os.Path.makeTempName() method.

Language directories for localized strings

When the app starts, the appropriate .42s string files will be loaded from the directory corresponding to the current language settings of the mobile device. String files to be loaded can be defined in the app's fglprofile, or you can use the main program name to avoid fglprofile settings.

For each language supported by your application, a directory must exist under appdir, with a name including the locale codes. Default string files (in English for example) can be provided under appdir/defaults, in case the regional settings of the device do not match one of the locale directories of the app, otherwise the application will stop with error -8006.

For example:

appdir/defaults/mystrings.42s
appdir/fr/mystrings.42s
appdir/de/mystrings.42s

For more details, see Localized string files on mobile devices.

Deploying a custom fglprofile file

If you need to set fglprofile entries for your mobile application, create a file with the name fglprofile, and deploy it under the appdir directory, along with the other program files.

See Understanding FGLPROFILE for more details about fglprofile settings.

Creating the initial database file

When a mobile application starts for the first time, it typically creates a new database, or copies an existing database template file from the file directory (base.Application.getProgramDir) to the working directory (os.Path.pwd).

It is recommended that different database file names are used for the original and final application database, as folders pointed to by base.Application.getProgramDir() and os.Path.pwd() can be the same on Android devices.

For more details about database creation on mobile devices, see Creating a database from programs.