Files save to the internal storage, not to the SD card

Question

I'm using an HTC Desire 610 for Android development. I followed the examples in other answers to the same question, but all my file saves end up on internal device storage, and not the SD card. The phone definitely recognizes the SD card, and from within the phone I can transfer files to the SD card.

I tried hard-coding the file path to the SD card, and I also tried running the app while not plugged into the computer - all to no avail. It is extremely important that my app be able to save these files directly to the SD card. Any ideas?

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    writeDataToFile("2394872934729348");

}


public void writeDataToFile(String data){
    BufferedWriter bufferedWriter = null;

    String dataOutFileName = Environment.getExternalStorageDirectory().getAbsolutePath()+"/data.txt";

    try{
        bufferedWriter = new BufferedWriter(new FileWriter(dataOutFileName,true));
        bufferedWriter.write(data);
        bufferedWriter.flush();
    }
    catch (IOException e){
        e.printStackTrace();
    }
    finally {
        try {
            if(bufferedWriter != null){
                bufferedWriter.close();
            }
        } catch (IOException e){
            e.printStackTrace();
        }
    }

    MediaScannerConnection.scanFile(this,new String[]{dataOutFileName}, null,null);
}
}

EDIT: I'm now trying this. I get a FileNotFoundException unless I write directly to the package file (com.mypackage etc)

    File dataDir = new File("/storage/ext_sd/Data/");
    dataDir.mkdirs();
    File outputFile = new File(dataDir,"data.txt");

    try{
        FileOutputStream fos = new FileOutputStream(outputFile);
        OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fos);
        outputStreamWriter.write(data);
        outputStreamWriter.close();

    }
    catch (IOException e){
        Log.e("Exception", "File write failed: " + e.toString());
    }

Answer 1

To access the private storage directory on the external storage, use getExternalFilesDirs() , not getExternalStorageDirectory().

It will return an array with entries each location. The first entry in the array is considered the primary external storage and you should use that location unless it's full or unavailable. Refer Using the External Storage on Android API guides for detailed description.

Answer 2

Have you give to your app correct permissions in AndroidManifest.xml ? If you haven't done so already, you will need to give your app the correct permission to write to the SD Card by adding the line below to your Manifest:

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

Maybe that is the problem