Are there any good short code examples that simply read a new gmail message?

Question

I have been trying to write an app that periodically parses the contents of gmail messages. I have been through the JavaMail FAQ and I have looked at a number of examples in the JavaMail download package but have been unable to get this to work. The code below currently causes the following gmail error:

Host is unresolved: imaps.gmail.com:993

I have also tried imap.gmail.com:143 but get:

Host is unresolved: imap.gmail.com:143

Any help or advice would be greatly appreciated. GMailReader is the class I am using to try and return gmail imap messages:

public class GMailReader extends javax.mail.Authenticator { 
    private String mailhost = "imaps.gmail.com"; 
    private String user; 
    private String password; 
    private Session session; 
    public GMailReader(String user, String password) { 
        this.user = user; 
        this.password = password; 
        Properties props = new Properties(); 
        props.setProperty("mail.transport.protocol", "imaps"); 
        props.setProperty("mail.imaps.host", mailhost); 
        props.put("mail.imaps.auth", "true"); 
        props.put("mail.imaps.port", "993"); 
        props.put("mail.imaps.socketFactory.port", "993"); 
        props.put("mail.imaps.socketFactory.class", 
                  "javax.net.ssl.SSLSocketFactory"); 
        props.put("mail.imaps.socketFactory.fallback", "false"); 
        props.setProperty("mail.imaps.quitwait", "false"); 
        session = Session.getDefaultInstance(props, this); 
    } 
    public synchronized Message[] readMail() throws Exception { 
        try { 
            Store store = session.getStore("imaps"); 
            store.connect("imaps.gmail.com", user, password); 
            Folder folder = store.getFolder("INBOX"); 
            folder.open(Folder.READ_ONLY); 
            Message[] msgs = folder.getMessages(1, 10); 
            FetchProfile fp = new FetchProfile(); 
            fp.add(FetchProfile.Item.ENVELOPE); 
            folder.fetch(msgs, fp); 
            return msgs; 
        } catch (Exception e) { 
            Log.e("readMail", e.getMessage(), e); 
            return null; 
        } 
    } 
}

Answer 1

I found an example here that was helpful. My error was the use of "mail.transport.protocol" rather than "mail.store.protocol."

Answer 2

hereafter a corrected version of

public class GMailReader extends javax.mail.Authenticator { 
    private static final String TAG = "GMailReader";

    private String mailhost = "imap.gmail.com";  
    private Session session;
    private Store store;

    public GMailReader(String user, String password) {

        Properties props = System.getProperties();
        if (props == null){
         Log.e(TAG, "Properties are null !!");
        }else{
        props.setProperty("mail.store.protocol", "imaps");            

        Log.d(TAG, "Transport: "+props.getProperty("mail.transport.protocol"));
        Log.d(TAG, "Store: "+props.getProperty("mail.store.protocol"));
        Log.d(TAG, "Host: "+props.getProperty("mail.imap.host"));
        Log.d(TAG, "Authentication: "+props.getProperty("mail.imap.auth"));
        Log.d(TAG, "Port: "+props.getProperty("mail.imap.port"));
        }
    try {
        session = Session.getDefaultInstance(props, null);
        store = session.getStore("imaps");
        store.connect(mailhost, user, password);
        Log.i(TAG, "Store: "+store.toString());
    } catch (NoSuchProviderException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (MessagingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public synchronized Message[] readMail() throws Exception { 
    try { 
        Folder folder = store.getFolder("Inbox"); 
        folder.open(Folder.READ_ONLY);

        /* TODO to rework
        Message[] msgs = folder.getMessages(1, 10);
        FetchProfile fp = new FetchProfile(); 
        fp.add(FetchProfile.Item.ENVELOPE); 
        folder.fetch(msgs, fp);
        */
        Message[] msgs = folder.getMessages();
        return msgs; 
    } catch (Exception e) { 
        Log.e("readMail", e.getMessage(), e); 
        return null; 
    } 
} 
}

Bye

Answer 3

After a huge amount of trial, error and googling , snakeman's edition of this answer provided the workable example I needed for a gmail reader;

However others should be aware (if using later versions of the Android SDK) of Manifest permission requirements and the need to use asyncTask to move potentially long-running tasks out of the main UI thread), both of which are mentioned in this SMTP example

I should also mention that if, like me, you intend to also implement an smtp sending class, I have seen somewhere a discussion suggesting that session.getInstance should be used in place of session.getDefaultInstance.