Android 电子邮件客户端应用跟踪未读的 gmail 电子邮件

Question

所以我一直在使用 javamail API 作为我的 android 应用程序的一部分。登录到 gmail 帐户后，用户可以编写新电子邮件、查看收件箱和已发送的邮件。在适配器 class 的帮助下，电子邮件显示在列表视图中。（更准确地说，显示的是发件人、主题和发送日期，如果用户单击列表视图项目，那么邮件内容也会显示在新的 activity 上）。所有这些都运行良好。

我想以不同的方式显示未读电子邮件（在 gmail 客户端中也是未读的），例如如果邮件未读则将 textSyle 设置为粗体，但我在添加此功能时遇到了问题。我一直在尝试检查每封获取的电子邮件的标志，但出于某种原因，我在变量中看不到 these flags。

我用于获取邮件的代码片段（显示不在这里，在适配器 class 中）：

protected ArrayList<Email_Message> doInBackground(Void... args) {
        try {
            Properties properties = new Properties();
            properties.put("mail.store.protocol", "imaps");

            Session emailSession = Session.getDefaultInstance(properties);
            Store store = emailSession.getStore("imaps");
            store.connect("imap.gmail.com", username, password);

            // create the folder object and open it
            Folder emailFolder = store.getFolder("INBOX");
            emailFolder.open(Folder.READ_WRITE);
            Flags flags2 = emailFolder.getPermanentFlags(); //has 2 weird user flags in it ($phishing, $notphising) and systemflags = -2147483061 ???

            Flags seen = new Flags(Flags.Flag.RECENT);
            FlagTerm unseenFlagTerm = new FlagTerm(seen, false);
            Message messages2[] = emailFolder.search(unseenFlagTerm); //this will net the same result as getMessages(), only here for testing

            int test = emailFolder.getUnreadMessageCount(); //as far as i can tell this is working (i have 5000+ emails and 37 them are unread somewhere) but when i get a new email and the number goes up by 1 (38), and if i run the code again, after i already fetched the mails once, it's gonna be 37 again, and the mail marked as read in my gmail webclient too

            // retrieve the messages from the folder in an array and print it
            Message[] messages = emailFolder.getMessages();
            int j = messages.length - 1;
            for (int i = j - startIndex; i > j - startIndex - offset && i > (-1); i--) { //startIndex and offset are for displaying only 10 messages at the start and loading another 10 if the user scrolls to bottom
                if (isCancelled()){
                    break;
                }
                Email_Message mailMessage = new Email_Message(); //my class for storing email messages
                mailMessage.messageType = 1;
                //some tricks to get the address in the right format
                Address[] email_address = messages[i].getFrom();
                String tempAddress = email_address[0].toString();
                tempAddress = MimeUtility.decodeText(tempAddress);
                //still tempering with address, not important
                if(tempAddress.contains("=?")){
                    String[] AddressParts = tempAddress.split("\?=");
                    mailMessage.messageAddress = AddressParts[1].substring(2);
                }
                else {
                    mailMessage.messageAddress = tempAddress;
                }


                Flags flags = messages[i].getFlags(); //user_flags = null, system_flags = 32
                Flags.Flag[] systemflags = flags.getSystemFlags(); //has 1 item in it: bit = 32
                String str[]= flags.getUserFlags(); //empty, these are all true for all my mails, not just one
                mailMessage.messageDate = messages[i].getSentDate().toString();
                mailMessage.messageSubject = messages[i].getSubject();
                Object msgContent = messages[i].getContent();
                String content = ""; //getting the content of the mail with these multipart stuffs
                if (msgContent instanceof Multipart) { 

                    Multipart multipart = (Multipart) msgContent;

                    Log.e("BodyPart", "MultiPartCount: " + multipart.getCount());

                    for (int k = 0; k < multipart.getCount(); k++) {

                        BodyPart bodyPart = multipart.getBodyPart(k);

                        String disposition = bodyPart.getDisposition();

                        if (disposition != null && (disposition.equalsIgnoreCase("ATTACHMENT"))) {
                            DataHandler handler = bodyPart.getDataHandler();
                            content = handler.getName();
                        } else {
                            content = bodyPart.getContent().toString();
                        }
                    }
                } else
                    content = messages[i].getContent().toString();
                mailMessage.messageContent = content;
                EmailInbox.add(mailMessage);
            }
            // close the store and folder objects
            emailFolder.close(false);
            store.close();

        } catch (NoSuchProviderException e) {
            e.printStackTrace();
        } catch (MessagingException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return EmailInbox;
    }

我在代码中添加了一些注释来解释我在标志中发现的内容。我该怎么做才能完成这项工作？我已经预测到问题了，比如我只在我的应用程序中阅读未读邮件后会发生什么，将其标志设置为可见，当我再次启动 activity 并获取邮件时，它将再次成为未读邮件，因为我没有把它们存储在本地，但在我设法找到解决方案后，这是一个问题。

感谢您的帮助！

Answer 1

我不清楚你是如何寻找标志的。使用 messages[i].isSet(Flags.Flag.SEEN) 将告诉您是否设置了 SEEN 标志。请注意，SEEN 标志通常会在您访问邮件内容后立即设置，因此您不必自己设置。

提示：使用InternetAddress.toUnicodeString method, or get the name and address separately using the getPersonal and getAddress方法。这将避免任何需要自己解码的情况。

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