Writing to SD card on Android

What is the proper way of writing to the SD card on an Android device? I simply cannot get this working.
I have set Write Access in the Player Settings to "External (SDCard)" but Application.persistentDataPath returns "/mnt/sdcard/Android/data/com.x.x/files" which is the internal storage.

What is the universal solution for obtaining the correct path for the SD card on Android?

 

that is the "External storage" look at the documentation on google's site. where the user removable SD card mount location is different depending on manufacturer.

 

It is the "primary external storage" which is just a partition on the internal storage. I am looking for a way to get the path of the SD card.
Do you have a link to the Google documentation?

 

Here with this method you can get the external directory path

 

"Note: don't be confused by the word "external" here. This directory can better be thought as media/shared storage. It is a filesystem that can hold a relatively large amount of data and that is shared across all applications (does not enforce permissions). Traditionally this is an SD card, but it may also be implemented as built-in storage in a device that is distinct from the protected internal storage and can be mounted as a filesystem on a computer."

Again this is the "primary external storage" which is, at least on "newer" models, a part of the internal storage.
It really seems like Google don't want developers accessing an external SD card?

 

where the user removable SD card mount location is different depending on manufacturer.

 

Yes I understand that, but is there no way to get the path regardless of what phone is running the application?

 

You need to call native Android methods from your c# scripts to get the paths to internal and external storage within the Android Context of your running app. These methods should do just that.

Be sure to read the documentation for this if interested in what lies underneath.

Code (CSharp):

1.  
2. private String GetAndroidContextExternalFilesDir()
3. {
4.   string path = "";
5.  
6.   if (Application.platform == RuntimePlatform.Android)
7.   {
8.     try
9.     {
10.       using (AndroidJavaClass ajc = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
11.       {
12.         using (AndroidJavaObject ajo = ajc.GetStatic<AndroidJavaObject>("currentActivity"))
13.         {
14.           path = ajo.Call<AndroidJavaObject>("getExternalFilesDir", null).Call<string>("getAbsolutePath");
15.         }
16.       }
17.     }
18.     catch (Exception e)
19.     {
20.       Debug.LogWarning("Error fetching native Android external storage dir: " + e.Message);
21.     }
22.   }
23.   return path;
24. }
25.  
26. private String GetAndroidContextInternalFilesDir()
27. {
28.   string path = "";
29.  
30.   if (Application.platform == RuntimePlatform.Android)
31.   {
32.     try
33.     {
34.       using (AndroidJavaClass ajc = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
35.       {
36.         using (AndroidJavaObject ajo = ajc.GetStatic<AndroidJavaObject>("currentActivity"))
37.         {
38.           path = ajo.Call<AndroidJavaObject>("getFilesDir").Call<string>("getAbsolutePath");
39.         }
40.       }
41.     }
42.     catch (Exception e)
43.     {
44.       Debug.LogWarning("Error fetching native Android internal storage dir: " + e.Message);
45.     }
46.   }
47.   return path;
48. }
49.  

 

Excellent work. Thanks.

(A shame that - at least on Galaxy - you can't actually write to the returned external address.)

 

The upper answer is just the half solution. "GetExternalFilesDir" will give you one random external storage. In most cases it's the path to the emulated external storage, which is on the internal storage. If you want the path to the sd card you have to get all paths to all available external storages with "GetExternalFilesDirs" and then distinguish the sd card with its properties. Details and explanation can be found here: http://anja-haumann.de/unity-how-to-save-on-sd-card/

To get reliably the sd card path use this:

Code (CSharp):

1. private static string GetAndroidExternalFilesDir()
2. {
3.      using (AndroidJavaClass unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
4.      {
5.           using (AndroidJavaObject context = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity"))
6.           {
7.                // Get all available external file directories (emulated and sdCards)
8.                AndroidJavaObject[] externalFilesDirectories = context.Call<AndroidJavaObject[]>("getExternalFilesDirs", null);
9.                AndroidJavaObject emulated = null;
10.                AndroidJavaObject sdCard = null;
11.  
12.                for (int i = 0; i < externalFilesDirectories.Length; i++)
13.                {
14.                     AndroidJavaObject directory = externalFilesDirectories[i];
15.                     using (AndroidJavaClass environment = new AndroidJavaClass("android.os.Environment"))
16.                     {
17.                         // Check which one is the emulated and which the sdCard.
18.                         bool isRemovable = environment.CallStatic<bool ("isExternalStorageRemovable", directory);
19.                         bool isEmulated = environment.CallStatic<bool> ("isExternalStorageEmulated", directory);
20.                         if (isEmulated)
21.                             emulated = directory;
22.                         else if (isRemovable && isEmulated == false)
23.                             sdCard = directory;
24.                     }
25.                }
26.                // Return the sdCard if available
27.                if (sdCard != null)
28.                     return sdCard.Call<string>("getAbsolutePath");
29.                else
30.                     return emulated.Call<string>("getAbsolutePath");
31.             }
32.       }
33. }

 

Thanks so much!, I needed this.

 

Hi, AuriAuri. I am trying to get the sdcard from a Galaxy GT-I8262B (Android 4.1.2)with your code, but I am having the error :

java.lang.NoSuchMethodError: no non-static method with name='getExternalFilesDirs' signature='(Ljava/lang/Object; [Ljava/lang/Object;' in class Ljava.lang.Object.

I am looking for a solution for days, without success.

There is some thing I am doing wrong?

Thanks.​

 

I'm also having this same problem. It worked for me before but now it doesn't.

This is my error.

06-25 12:07:32.021: E/Unity(4018): AndroidJavaException: java.lang.NoSuchMethodError: no non-static method with name='getExternalFilesDirs' signature='()[Ljava/lang/Object;' in class Ljava.lang.Object;

It's surpising how little info about getting an Android external SD location is.

Any help would be greatly appreciated.

Phil

 

I managed to get in touch with the developer who made the original code and they found an issue on 2019. They've corrected it on their website now which you can checkout here:
http://anja-haumann.de/unity-how-to-save-on-sd-card/

I hope this helps anyone else whos having problems with this.