I'm using Bluestacks for testing my app, because I don't have Androids lying around. I'm tring to write a file to the SDCard but can't seem to figure out the path for it. I've tried the following: /mnt/sdcard/ext_sd & /mnt/extSdCard but neither of those worked.
I've tried the following: /mnt/sdcard/ext_sd & /mnt/extSdCard but
neither of those worked.
You should not hardcode paths. Because SD card storage location or path varies from phone to phone. SD card storage location in my phone is /storage/sdcard1
Now coming to your question,
Before API level 19, there was no official API method to store in SD card. But, many could do it using unofficial libraries or APIs.
Officially, one method (getExternalFilesDirs) was introduced in Context class in API level 19 (Android version 4.4 - Kitkat).
File[] getExternalFilesDirs (String type)
It returns absolute paths to application-specific directories on all
shared/external storage devices where the application can place
persistent files it owns. These files are internal to the application,
and not typically visible to the user as media.
That means, it will return paths to both types Storage - Internal memory and Micro SD card. Generally, second returned path would be storage path of micro SD card(but not always). So you need to check it out by executing the code with this method.
Instead of hardcoding paths, you should use this method in your app source code to get the SD card location. Then, write files to that location.
If you want to know more about storage location or paths in Android, please go through my other answer
getExternalFilesDir(null) is returning the path of the emulated sd card i.e internal to the phone but not the path removable sd card
how i can find the data directory of app on removable storage
'External' means not internal and internal means private if we translate Android English to real life English. External storage is the place that all apps can access and use.
Since the question is a bit vague then the answer must be.
SD card can be mapped to internal storage or external storage, but this is fairly new technology.
If you want to access SD card using in versions earlier than Android 5.0 (API 21) then you can use Environment.getExternalStorageDirectory();
Otherwise you must use Storage Access Framework to do it.
This question already has answers here:
Find location of a removable SD card
(24 answers)
Closed 6 years ago.
Long time iOS developer, advanced Android programmer (but not as advanced as I thought.. LOL)..
Trying to understand Android device storage options. On my android device I have an 14Gig SD Card.
When I write code
String strDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS)+ File.separator + "MyFolder";
it gets placed in a "Documents folder" on the internal device (when viewed with File Manager).
The path appears to be
storage/emulated/0
and my sd card (acording to the File Manager) is
storage/extSdCard
Why does Environment.getExternalStoragePublicDirectory give me a path to my intneral card?
What am I missing that gets me to a path to store files to the external card. I think I understand part of this is do to OS changes in SD Card access in 4.1 but not sure what I'm missing.
I've read through Environment.getExternalStorageDirectory does not return the path to the removable storage and still not clear. My app currently stores files using getExternalStoragePublicDirectory, however my users are requesting they have the option of storing it on the SDCard instead?
Why does Environment.getExternalStoragePublicDirectory give me a path to my intneral card?
Because external storage is not removable storage. Neither of those are internal storage.
however my users are requesting they have the option of storing it on the SDCard instead?
On Android 4.4+, either use the Storage Access Framework (to allow the user to choose a storage location, including removable storage, Drive/Dropbox/other cloud providers, etc.), or use getExternalFilesDirs() on Context. The latter method returns a File[] — if there are 2+ elements in the array, all but the first are locations on removable storage that you can read from and write to. You cannot write to arbitrary locations on removable storage on devices that ship with Android 4.4+.
I have created one app which creates one file on external memory, but when I install it on different devices the files are created in internal sdcard in some device and not created in external(Physical) sd card.
My question is that. How do we decide between the internal or external sdcard.
Which has more preference to store file by default in android?
I use the
Environment.getExternalStorageDirectory()+ "PolicyTaskfile"+"/filename.txt";
It gives external or internal sdcard path depending on the device.
The short answer is that you do not get to pick. It's up to the OEM to decide whether external storage is truly SD card or just an internal storage device (for example: eMMC). With KitKat there is a notion of primary and secondary external storage, but no easy API to determine which you are using or which is really removable media.
From the official documentation:
Using the External Storage
Every Android-compatible device supports a shared "external storage"
that you can use to save files. This can be a removable storage
media (such as an SD card) or an internal (non-removable)
storage ...
I'm really confused about this subject. From what I understand, using external storage doesn't necessarily mean to use a removable card, am I right? However, when talking about external storage, it's always referred as "sd card".
I'm developing an app that downloads .mp3 files from the internet. I want to save those files in the phone memory (don't want to use any removable device) but for what I have learned, those files have to be saved in external memory.However, I would like to offer the possibility of importing a file from a removable device. Where and how should I save those files?
Thanks
Difference between Internal Storage, External Storage (aka primary external storage) and Secondary External Storage?
Internal Storage: is storage that is not accessible by the user, except via installed apps (or by rooting their device). Example: data/data/app_packageName
External Storage has two types:
Primary External Storage: In built shared storage which is "accessible by the user by plugging in a USB cable and mounting it as a drive on a host computer". Example: When we say Nexus 5 32 GB.
Secondary External Storage: Removable storage. Example: SD Card.
When building an app that uses the internal storage, the Android OS creates a unique folder, which will only be accessible from the app, so no other app, or even the user, can see what's in the folder.
The external storage is more like a public storage, so for now, it's the sdcard, but could become any other type of storage (remote hard drive, or anything else).
The internal storage should only be used for application data, (preferences files and settings, sound or image media for the app to work).
If you intent to download many mp3s, i'd reccomend saving them to external storage, as the external storage is often bigger. Besides, storing data on the internal storage may prevent the user to install other applications.
The Internal and External Storage terminology according to Google/official Android docs is quite different from what we think.
According to official Android docs:-
Internal Storage: By default, files saved to the internal storage are private to your application and other applications cannot access them. When the user uninstalls your application, these files are removed/deleted. Your app user also can't access them using file manager; even after enabling "show hidden files" option in file manager. To access files in Internal Storage, you have to root your Android phone. So, this is NOT what we think as internal memory of the phone - Nexus 5's 32 GB internal memory.
External Storage:
This can be a removable storage media (such as an SD card) or an
internal (non-removable) storage
That means, both storage types like Nexus 6P's 64 GB internal memory and removable microSD card which we insert in phone's card slot are considered as External Storage.
Removable Storage means just microSD card storage, not the internal memory.
To store your app files in SD card, you may use File[] getExternalFilesDirs (String type) method in Context class. Generally, second returned path would be the storage path for microSD card (if any).
Note: I have edited - made my answer more useful after #Tunaki's comment.
From the Developer docs
All Android devices have two file storage areas: "internal" and "external" storage. These names come from the early days of Android, when most devices offered built-in non-volatile memory (internal storage), plus a removable storage medium such as a micro SD card (external storage). Some devices divide the permanent storage space into "internal" and "external" partitions, so even without a removable storage medium, there are always two storage spaces and the API behavior is the same whether the external storage is removable or not.
I think in the operating system, it defines external storage as anything not related to the actual OS filestructure. If you recall, when you write to 'internal storage', Android will make a folder privately for your application. So basically, if this is a hidden folder of some kind, it would mean that external storage could qualify as anything not being automatically hidden or managed directly by the OS. So this would mean that it would be up to the phone manufacturer about the definition of internal storage, as they could have 1 main piece of internal flash memory with two partitions on it. One partition meant to hold the os and the other meant to let you store everything on the phone.
Basically what I'm saying is: That's more a hardware related thing, and that the concept of 'external storage' could extend even to extra internal storage (flash memory) that the manufacturer added in. You could even consider storage options defined by the user as external storage as well.
Here's an updated answer for the latest Android (currently Android 13).
Internal storage used to mean the phone's internal memory and external storage used to mean, among other things, any inserted SD cards. Nowadays, this is not really the case because phones don't have SD cards any more. Phones without SD card slots still have "external storage" from the point of view of an app (eg Environment.getExternalStorageDirectory() still returns a valid location), but it's emulated - meaning it's actually a slice of internal storage.
This means one of the big differences between external and internal storage - which was that external was slower but bigger and internal fast and small - is no longer true.
Since Android 11, external storage has been scoped. This means apps get a folder of their own which is readable to them and unreadable to any other app (though see below). They can access this folder without permissions. Again, this brings external storage in line with internal. (Note scoped storage actually appeared in Android 10 but has only been enforced since Android 11).
But there are remaining differences between internal and external.
One big difference is that apps can still get a permission to read/write across all of external storage (MANAGE_EXTERNAL_STORAGE). This is hard to come by - users need to manually enable it by going into Settings, and apps which implement it are severely limited on the Play Store.
But it does mean that data written to external storage is less secure than that written to internal. Other apps may be able to eavesdrop on external.
The above is the TL;DR but there's a bit more to it. Here's a good article: https://medium.com/#tdcolvin/demystifying-internal-vs-external-storage-in-modern-android-c9c31cb8eeec