First you need following "javamail-android" libraries: (
download)
- additionnal.jar
- mail.jar
- activation.jar
Copy them to \libs folder and add copied jars to your project library.
You need following permissions:
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.USE_CREDENTIALS" />
OAuth2Authenticator.java:
import android.accounts.Account;
import android.accounts.AccountManager;
import android.accounts.AccountManagerCallback;
import android.accounts.AccountManagerFuture;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import com.sun.mail.smtp.SMTPTransport;
import com.sun.mail.util.BASE64EncoderStream;
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;
public class OAuth2Authenticator {
private static Session mSession;
private AccountManager mAccountManager;
private String mToken;
private Account mAccount = null;
private Activity mActivity;
private static String TEST_ACCOUNT_EMAIL = "(your_account_that_is_added_to_Android_device)@gmail.com";
public OAuth2Authenticator(Activity activity) {
mActivity = activity;
mAccountManager = AccountManager.get(mActivity);
Account[] accounts = mAccountManager.getAccounts();
// For this tutorial, we manually set the email account(TEST_ACCOUNT_EMAIL). However, you should create some kind of UI for users to select the Gmail account
for (Account a : accounts) {
if (a.name.equals(TEST_ACCOUNT_EMAIL) && a.type.equals("com.google")) {
mAccount = a;
}
}
if (mAccount != null) {
AccountManagerFuture<Bundle> future = mAccountManager.getAuthToken(mAccount, "oauth2:https://mail.google.com/", null, mActivity, new OnTokenAcquired(), null);
}
}
private class OnTokenAcquired implements AccountManagerCallback<Bundle> {
@Override
public void run(AccountManagerFuture<Bundle> result) {
try {
Bundle bundle = result.getResult();
mToken = bundle.getString(AccountManager.KEY_AUTHTOKEN);
new SendMailTask().execute();
} catch (Exception e) {
Log.e("OnTokenAcquired", e.getMessage());
}
}
}
private class SendMailTask extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... params) {
try {
sendMail("subject", "body message", TEST_ACCOUNT_EMAIL, mToken, "(recipient_address)@(somemail).com");
} catch (Exception e) {
Log.e("SendMailTask", "error:" + e.getMessage());
}
return null;
}
}
private 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");
mSession = Session.getInstance(props);
mSession.setDebug(debug);
final URLName unusedUrlName = null;
SMTPTransport transport = new SMTPTransport(mSession, unusedUrlName);
// If the password is non-null, SMTP tries to do AUTH LOGIN.
final String emptyPassword = null;
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(mSession);
DataHandler handler = new DataHandler(new ByteArrayDataSource(body.getBytes(), "text/plain"));
message.setSender(new InternetAddress(user));
message.setSubject(subject);
message.setDataHandler(handler);
if (recipients.indexOf(',') > 0)
message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(recipients));
else
message.setRecipient(Message.RecipientType.TO, new InternetAddress(recipients));
smtpTransport.sendMessage(message, message.getAllRecipients());
} catch (Exception e) {
Log.e("sendMail", e.getMessage());
}
}
}
MainActivity.java:
new OAuth2Authenticator(this);
