Writing to external SD card in Android 5.0 and above

Android: EACCES (Permission denied)

Writing files in Android system is easy with respect to internal storage, but when it comes to writing in external removable storage it may be a problem after android 4.4 release.

Apart from android 6 permission we need to gain permission to write in external removable storage, as it can throw a EACCES (Permission denied) Error even if android.permission.WRITE_EXTERNAL_STORAGE is granted.

So the following code will ensure that you can write in External media with the necessary permission apart from android.permission.WRITE_EXTERNAL_STORAGE.

Call the following function to open the system dialog to gain access with external removable storage.

Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE);
startActivityForResult(intent, 42);

also the Activity Result Listener as follows:

@Override

    public void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (resultCode == RESULT_OK && requestCode==42) {

            treeUri = data.getData();
//Todo the following step to make Persist access permissions

            final int takeFlags = data.getFlags()& (Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
 getActivity().getContentResolver().takePersistableUriPermission(treeUri, takeFlags);

        }

    }

To access/use file the following code:

DocumentFile pickedDir = DocumentFile.fromTreeUri(getContext(),treeUri);

DocumentFile createFolder=pickedDir.createDirectory("Hello");

DocumentFile newFile= createFolder.createFile("*","my.txt");

                try {

                    OutputStream out = getContext().getContentResolver().openOutputStrea(newFile.getUri());

                    out.write("Finally Writing”.getBytes());

                    out.close();

                }catch (Exception e){

                    Log.wtf("Error",e.toString());

                }

Overall code Snippet:

import java.io.OutputStream;

import android.content.Intent;

import android.net.Uri;

import android.support.v4.provider.DocumentFile;

public class Main extends AppCompatActivity {

@Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE);

                startActivityForResult(intent, 42);

}

@Override

    public void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (resultCode == RESULT_OK && requestCode==42) {

            Uri treeUri = data.getData();

//Todo the following step to make Persist access permissions

            final int takeFlags = data.getFlags()& (Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
 getActivity().getContentResolver().takePersistableUriPermission(treeUri, takeFlags);

DocumentFile pickedDir = DocumentFile.fromTreeUri(getContext(),treeUri);

                DocumentFile createFolder=pickedDir.createDirectory("Hello");

                DocumentFile newFile= createFolder.createFile("*","my.txt");

                try {

                    OutputStream out = getContext().getContentResolver().openOutputStream(newFile.getUri());

                    out.write("Finally Writing”.getBytes());

                    out.close();

                }catch (Exception e){

                    Log.wtf("Error",e.toString());

                }

        }

    }

}

You can also save the URI for further use if you don’t want to ask for the permission again and again using SharedPreferences or File or database etc. whatever suits you.

To check weather Permission is granted on a Folder, use following

final List<UriPermission> list = rootView.getContext().getContentResolver().getPersistedUriPermissions();