external-internal storage

Question

In android, whats the difference between external storage that is nonremovable (internal) and the internal storage? I am not sure where to save my data. I just need to save a game stats that a person can pull anytime they want

Thank you

Answer 1

Further to Chris' answer if you are concerned about external storage (SD card), not being avilable you can simply check this every time your app loads up and then pull in the relvent information accordingly.

You can use something like this:

if(isSDPresent)
{
    // SD Card is present
    // Your code goes here, files will be located @ /mnt/sdcard/Android/data/packagename
}
else
{
    // SD Card is not presenet
    // files located here /data/data/packagename
}

If you are testing on an emulator, you can load up your DDMS and find all the files stored in the revlent places.

Hope this helps.

Answer 2

In many newer devices there will no longer be a physical distinction, with "internal" and "external" storage sharing the same flash chips without necessarily even having fixed allocation, so the difference really remains one of intended access paradigm.

Files on the external storage (real or simulated) are unavoidably shared with everything, and modifiable by anything with that manifest permission. Traditionally they are easily visible, though with the recent MTP-access devices the system may need to be told about them before a connected PC will see them.

In contrast, files on the internal storage are private to an application, excepting anything running as root or system, or if the application has decided to make them generally visible or changeable. Even when accessible, data on the internal storage can be more difficult to access outside the owning app - it's not supported by the consumer-targeted USB Mass Storage or MTP mechanisms, and even for other apps and development tools it is tricky to locate unless you know where to look, as while you may be able to examine files folders which applications have chosen to share, you cannot browse through the parent (typically /data or /data/app) folders. It can be a bit frustrating even for the developer of an app to access the files it creates on private storage during debugging (though while the apk is debuggable it is possible with the run-as tool and adb, or you can build an export capability in to the app, or run on the emulator where adb has root).

Likely your decisions process should be something like this: Is it meant to be private to the owning application? If so, put it on the internal storage, unless it's too big and targeted at older devices, in which case you may need to encrypt and/or sign it for protection before placing on the external storage. Otherwise, if it's meant to be shared, needs to be handed to arbitrary other components (email app, etc), or is big, put it on the external storage.

Answer 3

In android, whats the difference between external storage that is nonremovable (internal) and the internal storage?

External storage never meant removable. It always meant "accessible by the user by plugging in a USB cable and mounting it as a drive on a host computer". Early Android devices happened to have removable external storage, but that was never the definition.

Internal storage is storage that is not accessible by the user, except via installed apps (or by rooting their device).