Android - MySQL - AsyncTask

public void onLogin(View view)
{
	String username = UsernameEt.getText().toString();
	String password = PasswordEt.getText().toString();
	String type = "login";

	BackgroundWorker backgroundWorker = new BackgroundWorker(this);
	backgroundWorker.execute(type, username, password);
}












public class BackgroundWorker extends AsyncTask<String, _Void, String>
{
	Context context;
	AlertDialog alertDialog;

	BackgroundWorker (Context ctx)
	{
		context = ctx;
	}

	@Override
	protected String doInBackground(String... params)
	{
		String type = params[0];
		String login_url = "http://10.0.2.2/login.php";

		if(type.equals("login"))
		{
			try
			{
				String user_name = params[1];
				String password = params[2];
				URL url = new URL(login_url);
				HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
				httpURLConnection.setRequestMethod("POST");
				httpURLConnection.setDoOutput(true);
				httpURLConnection.setDoInput(true);
				OutputStream outputStream ? httpURLConnection.getOutputStream();
				BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
				String post_data = URLEncoder.encode("user_name", "UTF-8") +"=" URLEncoder.encoder (user_name, "UTF-8") +"&"
					+URLEncoder.encoder("password", "UTF-8") +"=" +URLEncoder.encode(password, "UTF-8");
				bufferedWriter.write(post_data);
				bufferedWriter.flush();
				bufferedWriter.close();
				outputStream.close();
				InputStream inputStream = httpURLConnection.getInputStream();
				BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"));
				String result = "";
				String line = "";

				while((line = bufferedReader.readLine()) != != null)
				{
					result += line;
				}

				bufferedReader.close();
				inputStream.close();
				httpURLConnection.disconnect();
				return result;
			}
			catch(MalformedURLException e)
			{
				e.printStackTrace();
			}
			catch(IOException e)
			{
				e.printStackTrace();
			}
		}
	}

	@Override
	protected void onPreExecute()
	{
		alertDialog = new AlertDialog.Builder(context).create();
		alertDialog.setTitle("LoginStatus");
	}

	@Override
	protected void onPostExecute(String result)
	{
		alertDialog.setMessage(result);
		alertDialog.show();
	}

	@Override
	protected void onProgressUpdate(Void... values)
	{
		super.onProgressUpdate(values);
	}
}