[Gmail API] Send Mail

Send Gmail in Android.

and forward, reply, all-reply

 public static void sendMail(Context context, Account account, MailDetailObject mailDetailObject, String mailId, GmailNetworkListener listener) {
        try {
            GoogleAccountCredential credential = GoogleAccountCredential.usingOAuth2(context, Collections.singleton(MAIL_SCOPE));
            credential.setSelectedAccount(account);

            Gmail service = new Gmail.Builder(HTTP_TRANSPORT, JSON_FACTORY, credential).build();

            new SendMailTask(account, service, mailDetailObject, mailId, listener).execute();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static class SendMailTask extends AsyncTask<Void, Void, Message> {

        private Account account;
        private Gmail service;
        private MailDetailObject mailDetailObject;
        private String mailId;
        private List<MailAttachmentObject> ATTACHMENTS;
        private GmailNetworkListener listener;

        public SendMailTask(Account account, Gmail service, MailDetailObject mailDetailObject, String mailId, GmailNetworkListener listener) {
            this.account = account;
            this.service = service;
            this.mailDetailObject = mailDetailObject;
            this.mailId = mailId;
            this.ATTACHMENTS = new ArrayList<>();
            this.listener = listener;
        }

        @Override
        protected Message doInBackground(Void... voids) {
            if (listener == null) return null;

            try {
                Message message = null;
                if (mailId != null) {
                    message = service.users().messages().get(account.name, mailId).setFormat("raw").execute();

                    Base64 base64Url = new Base64(true);
                    byte[] emailBytes = base64Url.decodeBase64(message.getRaw());

                    Properties props = new Properties();
                    Session session = Session.getDefaultInstance(props, null);

                    MimeMessage origiMessage = new MimeMessage(session, new ByteArrayInputStream(emailBytes));

                    message = createMessage(mailDetailObject, origiMessage);
                } else {
                    message = createMessage(mailDetailObject, null);
                }
                return service.users().messages().send(account.name, message).execute();
            } catch (Exception e) {
                e.printStackTrace();
                listener.onFailure(e.toString());
            }
            return null;
        }

        @Override
        protected void onPostExecute(Message result) {
            super.onPostExecute(result);
            if (listener != null) {
                listener.onSuccess(result);
            }
        }

        private Message createMessage(MailDetailObject mailDetailObject, MimeMessage originMessage) throws Exception {
            if (mailDetailObject.TO.size() == 0 || mailDetailObject.FROM == null) {
                return null;
            }

            if (originMessage != null) {
                getAttachmentItem(originMessage.getContent());
                mailDetailObject.ATTACHMENTS.addAll(this.ATTACHMENTS);
            }

            Properties props = new Properties();
            Session session = Session.getDefaultInstance(props, null);

            MimeMessage message = new MimeMessage(session);
            message.setSubject(mailDetailObject.SUBJECT);
            message.setFrom(new InternetAddress(mailDetailObject.FROM.EMAIL, mailDetailObject.FROM.NAME));

            for (AccountObject item : mailDetailObject.TO) {
                message.addRecipient(javax.mail.Message.RecipientType.TO, new InternetAddress(item.EMAIL, item.NAME));
            }

            if (mailDetailObject.CC.size() > 0) {
                for (AccountObject item : mailDetailObject.CC) {
                    message.addRecipient(javax.mail.Message.RecipientType.CC, new InternetAddress(item.EMAIL, item.NAME));
                }
            }

            if (mailDetailObject.BCC.size() > 0) {
                for (AccountObject item : mailDetailObject.BCC) {
                    message.addRecipient(javax.mail.Message.RecipientType.BCC, new InternetAddress(item.EMAIL, item.NAME));
                }
            }

            if (mailDetailObject.ATTACHMENTS.size() == 0) {
                message.setContent(mailDetailObject.CONTENT.BODY, mailDetailObject.CONTENT.CONTENT_TYPE);
            } else {
                List<MailAttachmentObject> inlineFiles = new ArrayList<>();
                List<MailAttachmentObject> attachFiles = new ArrayList<>();

                for (MailAttachmentObject item : mailDetailObject.ATTACHMENTS) {
                    if (item.IS_INLINE.equals("true")) {
                        inlineFiles.add(item);
                    } else {
                        attachFiles.add(item);
                    }
                }

                MimeBodyPart mimeBodyPart = new MimeBodyPart();
                mimeBodyPart.setContent(mailDetailObject.CONTENT.BODY, mailDetailObject.CONTENT.CONTENT_TYPE);

                MimeMultipart mimeMultipart = null;

                if (inlineFiles.size() > 0) {
                    mimeMultipart = new MimeMultipart();
                    mimeMultipart.setSubType("related");
                    mimeMultipart.addBodyPart(mimeBodyPart);

                    for (MailAttachmentObject item : inlineFiles) {
                        if (item.CONTENT != null && item.CONTENT.length() > 0) {
                            MimeBodyPart inlinePart = new PreencodedMimeBodyPart("base64");
                            inlinePart.setContent(item.CONTENT, item.FILE_TYPE);
                            inlinePart.setContentID("<" + item.CONTENT_ID + ">");
                            inlinePart.setDisposition(MimeBodyPart.INLINE);
                            mimeMultipart.addBodyPart(inlinePart);
                        } else if (item.CONTENT_ORIGINAL != null && item.CONTENT_ORIGINAL.length() > 0) {
                            MimeBodyPart inlinePart = new MimeBodyPart();
                            inlinePart.attachFile(item.CONTENT_ORIGINAL, item.FILE_TYPE, "base64");
                            inlinePart.setContentID("<" + item.CONTENT_ID + ">");
                            inlinePart.setDisposition(MimeBodyPart.INLINE);
                            mimeMultipart.addBodyPart(inlinePart);
                        }
                    }
                }

                if (inlineFiles.size() > 0 && attachFiles.size() > 0) {
                    mimeBodyPart = new MimeBodyPart();
                    mimeBodyPart.setContent(mimeMultipart);
                }

                if (attachFiles.size() > 0) {
                    mimeMultipart = new MimeMultipart();
                    mimeMultipart.setSubType("mixed");
                    mimeMultipart.addBodyPart(mimeBodyPart);

                    for (MailAttachmentObject item : attachFiles) {
                        if (item.CONTENT != null && item.CONTENT.length() > 0) {
                            MimeBodyPart attachFile = new PreencodedMimeBodyPart("base64");
                            attachFile.setContent(item.CONTENT, item.FILE_TYPE);
                            attachFile.setFileName(item.FILE_NAME);
                            attachFile.setDisposition(MimeBodyPart.ATTACHMENT);
                            mimeMultipart.addBodyPart(attachFile);
                        } else if (item.CONTENT_ORIGINAL != null && item.CONTENT_ORIGINAL.length() > 0) {
                            MimeBodyPart attachFile = new MimeBodyPart();
                            attachFile.attachFile(item.CONTENT_ORIGINAL, item.FILE_TYPE, "base64");
                            attachFile.setDisposition(MimeBodyPart.ATTACHMENT);
                            mimeMultipart.addBodyPart(attachFile);
                        }
                    }
                }

                message.setContent(mimeMultipart);
            }
            return createFromMimeMessage(message);
        }

        private Message createFromMimeMessage(MimeMessage email) throws IOException, MessagingException {
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            email.writeTo(baos);
            String encodedEmail = Base64.encodeBase64URLSafeString(baos.toByteArray());
            Message message = new Message();
            message.setRaw(encodedEmail);
            return message;
        }

        private void getAttachmentItem(Object content) throws Exception {
            if (content instanceof MimeMultipart) {
                MimeMultipart multipart = (MimeMultipart) content;
                for (int i = 0; i < multipart.getCount(); i++) {
                    MimeBodyPart bp = (MimeBodyPart) multipart.getBodyPart(i);
                    if (bp.getFileName() != null && bp.getFileName().length() > 0) {
                        this.ATTACHMENTS.add(new MailAttachmentObject(bp));
                    } else {
                        getAttachmentItem(bp.getContent());
                    }
                }
            }
        }
    }