Question

I currently use Environment.getExternalStorageDirectory() to obtain a location where I can store some data temporarily and then after being used gets deleted. This data can range from 1-100MB.

This works fine but on some cases the state of the external storage is removed or unmounted etc… and I can’t access to store my data…

My question is what could be a good fallback solution when this storage is not available?

I’m targeting Android 1.6 and greater.

Answer 1

Note that you should not use the path returned by Environment.getExternalStorageDirectory() directly:

Applications should not directly use this top-level directory, in
order to avoid polluting the user’s root namespace. Any files that are
private to the application should be placed in a directory returned by
Context.getExternalFilesDir, which the system will take care of
deleting if the application is uninstalled. Other shared files should
be placed in one of the directories returned by
getExternalStoragePublicDirectory(String).

Use the path returned by getFilesDir() to store files private to your app on the internal storage, or getExternalFilesDir() to store on the external storage.

If you’re storing data temporarily, consider using the cache directories.

These files will be ones that get deleted first when the device runs
low on storage.

Use the methods: getCacheDir() or getExternalCacheDir() on the external filesystem. Read the documentation for important differences between them.

If the size of the data to be stored is not large, you’d be better off using the internal storage. Otherwise, you’ll have to managing the complexity of detecting if external storage is available, falling backing to internal storage if not.