Waheed Khan Waheed Khan - 1 year ago 101
Android Question

Send Email in Service (without prompting user)

is it possible that I send email in background using service.. like in service I use Intent with ACTION_SENDTO with Uri data mailto:recipient_email and it get sent in the background without any user intervention .. or through default email app without prompting the user ...

Answer Source

The best solution is using the Gmail account to send the email.

Generally speaking:

  1. download mail.jar and activation.jar for android https://code.google.com/p/javamail-android/
  2. Connect to GMail to get the OAuth token
  3. Send the email

here's the code

import java.util.Properties;

import javax.activation.DataHandler;
import javax.mail.Message;
import javax.mail.Session;
import javax.mail.URLName;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.mail.util.ByteArrayDataSource;

import android.accounts.Account;
import android.accounts.AccountManager;
import android.accounts.AccountManagerCallback;
import android.accounts.AccountManagerFuture;
import android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;

import com.sun.mail.smtp.SMTPTransport;
import com.sun.mail.util.BASE64EncoderStream;

public class GMailSender {
    private Session session;
    private String token;

    public String getToken() {
        return token;

    public GMailSender(Activity ctx) {

    public void initToken(Activity ctx) {

        AccountManager am = AccountManager.get(ctx);

        Account[] accounts = am.getAccountsByType("com.google");
        for (Account account : accounts) {
            Log.d("getToken", "account="+account);  

        Account me = accounts[0]; //You need to get a google account on the device, it changes if you have more than one

        am.getAuthToken(me, "oauth2:https://mail.google.com/", null, ctx, new AccountManagerCallback<Bundle>(){
            public void run(AccountManagerFuture<Bundle> result){
                    Bundle bundle = result.getResult();
                    token = bundle.getString(AccountManager.KEY_AUTHTOKEN);
                    Log.d("initToken callback", "token="+token);    

                } catch (Exception e){
                    Log.d("test", e.getMessage());
        }, null);

        Log.d("getToken", "token="+token);

    public SMTPTransport connectToSmtp(String host, int port, String userEmail,
            String oauthToken, boolean debug) throws Exception {

        Properties props = new Properties();
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.starttls.required", "true");
        props.put("mail.smtp.sasl.enable", "false");

        session = Session.getInstance(props);

        final URLName unusedUrlName = null;
        SMTPTransport transport = new SMTPTransport(session, unusedUrlName);
        // If the password is non-null, SMTP tries to do AUTH LOGIN.
        final String emptyPassword = null;

        /* enable if you use this code on an Activity (just for test) or use the AsyncTask
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();

        transport.connect(host, port, userEmail, emptyPassword);

        byte[] response = String.format("user=%s\1auth=Bearer %s\1\1",
                userEmail, oauthToken).getBytes();
        response = BASE64EncoderStream.encode(response);

        transport.issueCommand("AUTH XOAUTH2 " + new String(response), 235);

        return transport;

    public synchronized void sendMail(String subject, String body, String user,
            String oauthToken, String recipients) {
        try {

            SMTPTransport smtpTransport = connectToSmtp("smtp.gmail.com", 587,
                    user, oauthToken, true);

            MimeMessage message = new MimeMessage(session);
            DataHandler handler = new DataHandler(new ByteArrayDataSource(
                    body.getBytes(), "text/plain"));
            message.setSender(new InternetAddress(user));
            if (recipients.indexOf(',') > 0)
                        new InternetAddress(recipients));
            smtpTransport.sendMessage(message, message.getAllRecipients());

        } catch (Exception e) {
            Log.d("test", e.getMessage(), e);


this code was originally posted here Javamail api in android using XOauth.

Please note to get the OAuth token you need an Activity and you have to ask the user which account to use. The token should be retrieved during the OnCreate phase and saved in the preferences. See also How to get the Android device's primary e-mail address

Alternatively you can use mail.jar but you have to ask the user for their username and password.

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