Android Emulated SD Card - android

I have an android device which doesn't have an SD Card (It says "Insert SD Card" in Settings -> Storage.
But when i list the files in adb shell, it has a folder named /sdcard in it and it has files in it too.
I thought that it might be an emulates sdcard location coming from /storage/sdcard0. But the contents of the two folders are different. Can anyone help me understand this concept please? Couldn't find much by Googling.

Related

Android v5.1.1 and SD card write issues

I have a Sony Z5 Compact phone with a brand new, Sandisk UHS-I U3 32GB SD card.
The card used to work for a while (like 3 weeks), but now something happened to that.
Phone is not able to write onto the card at all.
I tried formatting that from the Android, from Windows, nothing works.
Symptoms:
1.) after formatting, I can create folders and copy files onto the sd card on Windows.
2.) after formatting, I can create folders on the card on android.
3.) if I copy anything, really, anything from Windows to Android (to the card), the card will deny the next file write operations.
4.) seems like if it gets readonly, but mount shows sdcard1 as rw.
5.) after this, putting the card to Windows, it works okay (without formatting)
Question:
I want to format the SD card, and put back in the phone, and put some music onto that. (without having it corrupted).
Thank you.
Ps.: I hope this is some right forum for this.

Comparing sdcard paths

Device 1
/sdcard attached to real sd card
/mnt/sdcard attached to real sd card
Device 2
/sdcard attached to internal memory
/mnt/sdcard attached to internal memory
/external_storage(something like this) to real sd card
.
.
/sdcard and /mnt/sdcard seems to have the same location. Always ?
My question is, how do I know if they attached to same directory ?
I tried new File(path1).equals(new File(path2)); but it return false. Only way I see is, create a hidden file with unique id and check the existence in both paths.
PS : I'm aware of Environment.getExternalStorageDirectory(). But I need these paths for some specific purpose.
/sdcard and /mnt/sdcard are not always the same. There are many paths that can exsist such as:
/emmc
/mnt/sdcard/external_sd
/mnt/external_sd
/sdcard/sd
/mnt/sdcard/bpemmctest
/mnt/sdcard/_ExternalSD
/mnt/sdcard-ext
/mnt/Removable/MicroSD
/Removable/MicroSD
/mnt/external1
/mnt/extSdCard
/mnt/extsd
/mnt/usb_storage <-- usb flash mount
/mnt/extSdCard <-- usb flash mount
/mnt/UsbDriveA <-- usb flash mount
/mnt/UsbDriveB <-- usb flash mount
There should be no reason that you would need a direct path hard coded to the internal or external memory when they make functions available for that. Anything that you are hard coding will be the same as what you get back from the functions that you have listed only the will be for that specific devices.
This will give you a string of the absolute path to a file on the external storage:
String myPath = sdcardEnvironment.getExternalStorageDirectory().getAbsolutePath() + "/folder file is in/file you want path to";
And this will get you the path your applications internal storage:
this.getApplicationContext().getFilesDir()
You cannot always access the external SD card from code because of the way that newer versions of android partition itself. Here is statement directly from android dev site:
It's possible that a device using a partition of the internal storage for the external storage may also offer an SD card slot. In this case, the SD card is not part of the external storage and your app cannot access it
new File("/sdcard").getCanonicalPath().equals(new File("/mnt/sdcard").getCanonicalPath())
Omitted are exception handling and other niceties. Note, however, that ObieMD5 is correct, and you should not be doing this, as you can see from the list of paths in the answer above.
Also note that this method will only resolve symlinks; if your device uses mount instead to have the same space accessible from two locations, this method will not work.
attached to real sd card
The Android SDK, at present, has no concept of "real sd card". There is external storage. The definition of where external storage resides is up to the device manufacturer.
attached to internal memory
Those paths at best refer to external storage, and at worst do not exist.
/sdcard and /mnt/sdcard seems to have the same location. Always ?
No. Those paths may not even exist on some devices, as there is no requirement that they exist, and modern devices do not use those paths. Always use methods on Environment or Context to find locations on external storage.

How to access USB Path in android?

I am connected android device and PC via USB cable. My Internal SD Card location Path as /mnt/sdcard. But my External USB device path as /mnt/userdata1. I am try to use this code to find only the Internal SD Card Path Environment.getExternalStorageDirectory(). I am using this code to access only in the internal SD Card path. How to access the external USB Path.
For example Screenshot is here...
Example
In this example contains Internal Memory, External SD card and USB Storage. How to find this path ( Internal Memory, External SD card and USB Storage) programmatically. In this code Environment.getExternalStorageDirectory() is viewed files from all Internal Memory Files only. So how to access others path ( External SD card and USB Storage ) Please guide me with code. Thanks..
If I understand correctly, what you are calling "external" USB path is actually the mount point for your SD card on your computer. Most likely, your SD card has label userdata1. Therefore when it's mounted on the computer, it gets /mnt/userdata1 mount point. However this is not strictly necessary and it can be any mount point at all. In fact, if you connect it to another computer, it can easily be another mount point.
Because this path is determined by the computer operating system, you'll need to find this path on your computer (note that this can be different every time you connect your phone to your PC, so you'll need to do it every time).
From your question and path structure (/mnt/userdata1) I'm guessing you're using linux or some other unix version. Therefore you could run mount on your PC to see the list of the mounted devices. For example, here's the output on my mac:
$ mount
/dev/disk0s2 on / (hfs, local, journaled)
devfs on /dev (devfs, local, nobrowse)
map -hosts on /net (autofs, nosuid, automounted, nobrowse)
map auto_home on /home (autofs, automounted, nobrowse)
/dev/disk1s1 on /Volumes/ALEKS540 (msdos, local, nodev, nosuid, noowners)
Note the last line in the output - this is my connected android phone with the SD card mounted to the computer. On macs, the mount points are created under /Volumes instead of /mnt. Other than than, ALEKS540 is the label of my SD card, hence it's mounted this way.
Internally on the phone, it's still mounted as /mnt/sdcard.
From the point of view of Android, there may be three storage types:
Internal memory it's always mounted under / on the device and contains everything except the SD card and USB storage below.
SD card - this is referred to as "external storage" and is usually mounted as /mnt/sd, but not always. Environment.getExternalStorageDirectory() will return the path of SD card mount point.
USB storage - this is only supported on very few devices (those that support USB host mode for external storage). This will be mounted somewhere under /mnt, but the exact location will vary. You will need to use Android NDK to interrogate and iterate mounted devices to find the one you're after.

Need help about android mounting Sdcard

Im working on "mount ntfs sdcard"
That is problem:
- If i mount sdcard to another folder than /mtn/sdcard then my sdcard working find
- If i mount it to /mnt/sdcard then android not except it : " The SDcard is not currently mounted"
In adb shell i type mount command and see that my SDcard is mounted to /mnt/sdcard
But infact SDcard folder cannot accessable.
I think android doesnt except mount ntfs sdcard on /mnt/sdcard because it programed to mount vfat sdcard on /mnt/sdcard.
Now the question: where i can find mounting code or mounting procedure of android when we insert SDcard? i want to modify it to accept ntfs sdcard.
P/S: im on GB 2.3.6
This is a very specific question, I doubt you will get an answer here. You might want to try to locate it yourself from the source code which could be found here:
https://sites.google.com/a/android.com/opensource/download
I did some googling and found this:
http://cateee.net/lkddb/web-lkddb/NTFS_FS.html, you might need to modify it.
On Android, the mounting of the sdcard is managed by the vold daemon.
If you want a stable system, you likely need to either get vold to manage your custom mount, remove vold from the system and do it's entire job yourself, or somehow get it and your custom solution to stay out of each other's way.
Lots of custom ROMs have used vold in different ways - to partition an sdcard and add a unix-style filesystem for storing apps, to put an entire alternate android installation on an sdcard or tablet internal storage area, etc. You might get some ideas by looking at those, reading their development discussion history, etc.

Fetching Files from SD card and USB to different folders when using getExternalStorage()

Is it possible to sort the files detected from usb and SD Card seperately?.I mean I fornd that using getExternalStorage,we are able to detect all external devices connected to Android device which includes both SD card and USB.
I would like to seperate the files that are detected to 2 seperate folders(Now the files from SD card and USB are detected into same folder)..ie USB files seperately and SD card files seperately.
How to do it?Kindly help
You have to code in the logic to determine if the "external storage" is really external storage. Different devices use a different name - very stupid I agree. In Google's API doc's I'm pretty sure they mention that getExternalStorage() is not guaranteed to grab the external storage as this is manufacturer and device specific.
Knowing this pitfall may assist you in a solution.

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