external storage not available

Question

I want create new file and write/read app settings. isExternalStorageAvailable() return false and should true. Android emulator external memory = 200mb.

 boolean isExternalStorageAvailable() {
        String extStorageState = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(extStorageState)) {
            return true;
        }
        return false;
    }

Added permissions to manifest file:

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

Code:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    if (!isExternalStorageAvailable() || isExternalStorageReadOnly()) {
        saveButton.setEnabled(false);
        System.out.println("Available: "+isExternalStorageAvailable()+", ReadOnly: "+isExternalStorageReadOnly());
    }
    else {
        myExternalFile = new File(getExternalFilesDir(filepath), filename);
    }
}

I tried https://www.journaldev.com/9400/android-external-storage-read-write-save-file without success — , Jan 08 '18 at 10:39
Keep in mind that I'm not familiar with Android, but is it possible that `isExternalStorageAvailable()` is returning false because it simply isn't there and *not* that the program doesn't have permissions to use it? My advice would be to verify the type of external storage returned by `Environment.getExternalStorageState()`. — Neil, Jan 08 '18 at 10:40
Here you can see code + emulator + logcat: https://i.imgur.com/Gn5LlOn.png — , Jan 08 '18 at 10:54
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Demonick · Answer 1 · 2018-01-08T11:20:59.460

To get all external storage paths this can be used:

    File[] extSDCardPaths = null;
    try {
        extSDCardPaths = ContextCompat.getExternalFilesDirs(ctx, null);
    } catch (Exception e) {
        // handle
    }

    for (File f : extSDCardPaths) {
        if (Environment.isExternalStorageRemovable(f)) {
            // check if anything found
        }
    }

If extSDCardPaths returns something then ext storage is available.

The above works for > 4.4(KitKat) only

The below hack can be used as fallback for lower OS versions:

String[] fallback = {"/storage/sdcard1/", "/mnt/ext_card/", "/mnt/extSdCard/", "/storage/extsdcard/",
            "/mnt/extsdcard/", "/storage/extSdCard/", "/mnt/external_sd", "/storage/MicroSD/",
            "/storage/external_SD/", "/storage/ext_sd/", "/storage/removable/sdcard1/", "/mnt/sdcard/external_sd/",
            "/storage/ext_sd/", "/mnt/emmc/", "/data/sdext/", "/sdcard/sd/"};

   for (String path : fallback) {
        if (new File(path).exists()) {
                // found an ext. dir
            break;
        }
   }

"Unable to create external files directory" https://i.imgur.com/5flOFsw.png — , Jan 08 '18 at 11:13
See edited answer, if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) { // then do the fallback — Demonick, Jan 08 '18 at 11:21
Ye i use SDK 15. Tested without success: https://i.imgur.com/Nu2GPLs.png — , Jan 08 '18 at 12:06

score 0 · Answer 2 · answered Jan 08 '18 at 12:06

If your application is targeting and running on marshmallow or above, you must gain permission to read/write to external storage, you must request permission from user explicitly after declaring permission in manifest.

Make sure you have this in your manifest: <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Check for permission explicitly. If not provided, request it:

public void checkPermissionReadStorage(Activity activity){
         if (ContextCompat.checkSelfPermission(activity,      
Manifest.permission.READ_EXTERNAL_STORAGE) !=     
PackageManager.PERMISSION_GRANTED) {

        // Should we show an explanation?
        if (ActivityCompat.shouldShowRequestPermissionRationale(activity,
                Manifest.permission.READ_EXTERNAL_STORAGE)) {

            // Show an expanation to the user *asynchronously* -- don't block
            // this thread waiting for the user's response! After the user
            // sees the explanation, try again to request the permission.

        } else {

            // No explanation needed, we can request the permission.

            ActivityCompat.requestPermissions(activity,
                    new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},
                    MY_PERMISSIONS_REQUEST_READ_STORAGE);

            // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
            // app-defined int constant. The callback method gets the
            // result of the request.
        }
    }
}

Receive permission response:

@Override
public void onRequestPermissionsResult(int requestCode,
                                       String permissions[], int[] grantResults) {
    switch (requestCode) {
        case PermissionManager.MY_PERMISSIONS_REQUEST_READ_STORAGE:
            //premission to read storage
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                // Permission granted. Call your storage related code here

            } else {

                // permission denied.
                // Handle permission failed here.
            }
            return;


        // other 'case' lines to check for other
        // permissions this app might request
    }
}

Code was taken from here

I have SDK version 15 so should work without this code. But anyway i will test soon. — , Jan 08 '18 at 12:13
If you dont target api 23 or above, using the above approach is useless since the permissions are granted as soon as the application is installed. May be you are having a different issue then — Vijai, Jan 08 '18 at 12:19

external storage not available

2 Answers2