My app can write and delete file from the android sd card by adding the
android.permission.WRITE_EXTERNAL_STORAGE permission.
But this does not work with the external SD card some devices support. Writing to the default SD card (/mnt/sdcard0 in most cases) has no problem, but this does not work with the extra sd cards (/mnt/sdcard1 ).
I have googled about this and also gone through some threads in stackoverfolw itself, but still i am not able to find a proper solution.
Is it really a bug in android? Is there any workaround for this?
I will really appreciate any clarification on this.
You can get the path of sdcard from this code:
String path = Environment.getExternalStorageDirectory().getAbsolutePath();
Then specify the foldername and file name.
if you are using an emulator, double-check to make sure that you have filled in a value for the SD Card size.
Related
I want to give the user the option to save images on their sd card and I want to be able to calculate the sizes of folders of such images. I find that Environment.getExternalStorageDirectory() returns internal storage. The only way I can find the sd card is by using an ACTION_OPEN_DOCUMENT_TREE request. But this means I have to use DocumentFiles rather than regular Files. I can only get a content uri, not a direct path to the sd card itself.
So, File.length() works well with internal storage but DocumentFile.length() is extremely slow with external storage. Is there any way to get the size of a folder based on its content uri without it taking forever? Or can I somehow find an actual path to the sd card and use Files instead? I found a folder like /storage/3857-3732 but I don't seem to have permission to write to it (yes I have WRITE_EXTERNAL_STORAGE permission).
Now, I am working on data transmission using bluetooth. I have such problem in selecting file in SD card/ internal storage.
I am already put permission in manifest :
I am using this command to get access the file
File sdCard = Environment.getExternalStorageDirectory();
But when I am check using this command if (sdCard.canRead()) , it can't read the path.
Anyone have the solution within my problem? Thanks anyway
The Android Dev resources has a good guide on this.
Assuming you have all the correct permissions, you could be facing issues where the storage is not mounted or there is not enough space. The guide explains how to check the state of the External Storage Dir, etc.
Did you add the following line to the AndroidManifest?
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
From android SDK version 4, you need to add that line to access external storage by your app.
Some of other issues are, (Check whether phone detects the SD card)
SD Card is Not Clean
Battery Voltage
Card Slot is Squeezed
Metal Wires in the Card Slot Get Rusty and Twisted
Malware Invade SD Card
SD Card is not Formatted Properly
SD Card is Broken
The Phone Breakdown
problem solved.
The problem is related with new android SDK. We need to add additional permission.
Thanks everyone.
I am aware about changes in Access to SD card introduced by Google with Android 4.4. However in my application I need to be able to store data on some removable /secondary sd card.
When I create the application folder (app.xyz.com) on the secondary using default file manager then I am able to create dirs and files inside. But by default such dir dosen't exist on secondary sd card.
So, I would like to create the application specific dir programmatically inside my application…
Do you have any idea how to do this??? Simple file.mkdirs(), even with the correct application related path, doesn’t work. Permission error…
I have spend already two days trying to find a way, without any success
THANKS FOR YOUR HELP!!!
Do you have any idea how to do this?
Use getExternalFilesDirs() (note the plural). If that returns more than one entry, the second and subsequent ones are on removable media. Those directories you can read and write to without any permissions on Android 4.4.
I found that using Environment object isn't reliable;e to determinate SD card. Actually it works, however sometimes tells like as no SD card, so I use just direct mount as /sdcard and it works. Now I realized that a device may have several SD cards. My device report it as external-sdcard, so I can access this card as /external-sdcard or /sdcard/external-sdcard. Now question, how to figure out type of a particular mount? I can traverse directory, but File object doesn't have any attribute telling me I am SD card. I remember regular Java provides FileSystem objects which I can use to inspect particular files and this object can tell me if a File object is simple file, or it is drive, or it is external drive. Is something like that available for Android?
AFAIK, the currently documented API only supports one SD card (actually external storage).
You can use Environment.getExternalStorageDirectory() to get the directory, and Enviroment.getExternalStorageState() to check if it is mounted.
Anything besides that seems to be (currently) unsupported.
Bearing that in mind, you could parse /proc/mounts to find out what file systems are mounted where.
I am creating android application which contains DB that needs to be hidden(not able to access by the user)in the SD Card. Can anyone tell me how to do this?
Any file stored on the SD card is accessible both by applications running on the phone, and by users who have mounted the SD card (both while it's in the phone and otherwise).
You can change the file properties to make it 'hidden', but it will still be easily found. There is no way to make a file on a public partition like an SD Card 'secure' in the manner you describe - users will always be able to copy, delete, and potentially change the file.
The best solution to your problem is to look into ways to encrypt your database to record it securely. You won't be able to prevent users from deleting or copying the file, but you should be able to make it difficult for them to read data from it or modify its contents.
For an easy solution, just prefix the db file with a . (like .dbfile). This will hide the file on Linux based systems, including android.
I am assuming that you want to hide the file to prevent users from accidentally deleting/changing it.
SD cards cannot be secured in the fashion you seek.
just name the file start by ."Dot"... ".myFolder/.myfile"
You can create a folder whose name starts with a dot(.) example (.dbfiles) android See these folders as configuration folder and do not show content of these folder in applications like gallery,music player...You can see these folders with advance file explorer like Es File explorer
Sdcard you cant't! Internal app data partition is the place for you.