在没有用户交互的情况下发送电子邮件android

使用JavaMail API，它是专门为Android编写的。

import java.util.Date; 
import java.util.Properties; 
import javax.activation.CommandMap; 
import javax.activation.DataHandler; 
import javax.activation.DataSource; 
import javax.activation.FileDataSource; 
import javax.activation.MailcapCommandMap; 
import javax.mail.BodyPart; 
import javax.mail.Multipart; 
import javax.mail.PasswordAuthentication; 
import javax.mail.Session; 
import javax.mail.Transport; 
import javax.mail.internet.InternetAddress; 
import javax.mail.internet.MimeBodyPart; 
import javax.mail.internet.MimeMessage; 
import javax.mail.internet.MimeMultipart; 

public class Mail extends javax.mail.Authenticator { 
  private String _user; 
  private String _pass; 
  private String[] _to; 
  private String _from; 
  private String _port; 
  private String _sport; 
  private String _host; 
  private String _subject; 
  private String _body; 
  private boolean _auth; 
  private boolean _debuggable; 
  private Multipart _multipart; 

  public Mail() { 
    _host = "smtp.gmail.com"; // default smtp server 
    _port = "465"; // default smtp port 
    _sport = "465"; // default socketfactory port 
    _user = ""; // username 
    _pass = ""; // password 
    _from = ""; // email sent from 
    _subject = ""; // email subject 
    _body = ""; // email body 
    _debuggable = false; // debug mode on or off - default off 
    _auth = true; // smtp authentication - default on 
    _multipart = new MimeMultipart(); 
    // There is something wrong with MailCap, javamail can not find a handler for the multipart/mixed part, so this bit needs to be added. 
    MailcapCommandMap mc = (MailcapCommandMap) CommandMap.getDefaultCommandMap(); 
    mc.addMailcap("text/html;; x-java-content-handler=com.sun.mail.handlers.text_html"); 
    mc.addMailcap("text/xml;; x-java-content-handler=com.sun.mail.handlers.text_xml"); 
    mc.addMailcap("text/plain;; x-java-content-handler=com.sun.mail.handlers.text_plain"); 
    mc.addMailcap("multipart/*;; x-java-content-handler=com.sun.mail.handlers.multipart_mixed"); 
    mc.addMailcap("message/rfc822;; x-java-content-handler=com.sun.mail.handlers.message_rfc822"); 
    CommandMap.setDefaultCommandMap(mc); 
  } 
  public Mail(String user, String pass) { 
    this(); 
    _user = user; 
    _pass = pass; 
  } 
  public boolean send() throws Exception { 
    Properties props = _setProperties(); 
    if(!_user.equals("") && !_pass.equals("") && _to.length > 0 && !_from.equals("") && !_subject.equals("") && !_body.equals("")) { 
      Session session = Session.getInstance(props, this); 
      MimeMessage msg = new MimeMessage(session); 
      msg.setFrom(new InternetAddress(_from)); 
      InternetAddress[] addressTo = new InternetAddress[_to.length]; 
      for (int i = 0; i < _to.length; i++) { 
        addressTo[i] = new InternetAddress(_to[i]); 
      } 
        msg.setRecipients(MimeMessage.RecipientType.TO, addressTo); 
      msg.setSubject(_subject); 
      msg.setSentDate(new Date()); 
      // setup message body 
      BodyPart messageBodyPart = new MimeBodyPart(); 
      messageBodyPart.setText(_body); 
      _multipart.addBodyPart(messageBodyPart); 
      // Put parts in message 
      msg.setContent(_multipart); 
      // send email 
      Transport.send(msg); 
      return true; 
    } else { 
      return false; 
    } 
  } 
  public void addAttachment(String filename) throws Exception { 
    BodyPart messageBodyPart = new MimeBodyPart(); 
    DataSource source = new FileDataSource(filename); 
    messageBodyPart.setDataHandler(new DataHandler(source)); 
    messageBodyPart.setFileName(filename); 
    _multipart.addBodyPart(messageBodyPart); 
  } 
  @Override 
  public PasswordAuthentication getPasswordAuthentication() { 
    return new PasswordAuthentication(_user, _pass); 
  } 
  private Properties _setProperties() { 
    Properties props = new Properties(); 
    props.put("mail.smtp.host", _host); 
    if(_debuggable) { 
      props.put("mail.debug", "true"); 
    } 
    if(_auth) { 
      props.put("mail.smtp.auth", "true"); 
    } 
    props.put("mail.smtp.port", _port); 
    props.put("mail.smtp.socketFactory.port", _sport); 
    props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory"); 
    props.put("mail.smtp.socketFactory.fallback", "false"); 
    return props; 
  } 
  // the getters and setters 
  public String getBody() { 
    return _body; 
  } 
  public void setBody(String _body) { 
    this._body = _body; 
  } 
  // more of the getters and setters ….. 
} 

以下是如何在Android活动中使用Mail包装器的示例。

@Override 
public void onCreate(Bundle icicle) { 
  super.onCreate(icicle); 
  setContentView(R.layout.main); 
  Button addImage = (Button) findViewById(R.id.send_email); 
  addImage.setOnClickListener(new View.OnClickListener() { 
    public void onClick(View view) { 
      Mail m = new Mail("gmailusername@gmail.com", "password"); 
      String[] toArr = {"bla@bla.com", "lala@lala.com"}; 
      m.setTo(toArr); 
      m.setFrom("wooo@wooo.com"); 
      m.setSubject("This is an email sent using my Mail JavaMail wrapper from an Android device."); 
      m.setBody("Email body."); 
      try { 
        m.addAttachment("/sdcard/filelocation"); 
        if(m.send()) { 
          Toast.makeText(MailApp.this, "Email was sent successfully.", Toast.LENGTH_LONG).show(); 
        } else { 
          Toast.makeText(MailApp.this, "Email was not sent.", Toast.LENGTH_LONG).show(); 
        } 
      } catch(Exception e) { 
        //Toast.makeText(MailApp.this, "There was a problem sending the email.", Toast.LENGTH_LONG).show(); 
        Log.e("MailApp", "Could not send email", e); 
      } 
    } 
  }); 
} 

如果使用"smtp.gmail.com"作为默认smtp服务器，则会发出警告。

谷歌会强迫你经常更改你的链接电子邮件帐户密码，因为他们过于热心的"可疑活动"政策。本质上，它将不同国家在短时间内重复提出的smtp请求视为"可疑活动"。因为他们认为你(电子邮件账户持有人(一次只能在一个国家。

当谷歌系统检测到"可疑活动"时，它将阻止进一步的电子邮件，直到你更改密码。由于你将密码硬编码到应用程序中，每次发生这种情况时都必须重新发布应用程序，这并不理想。这种情况在一周内发生了3次，我甚至将密码存储在另一台服务器上，每次谷歌强迫我更改密码时都会动态提取密码。

因此，我建议使用许多免费的smtp提供商之一，而不是"smtp.gmail.com"来避免这个安全问题。使用相同的代码，但将"smtp.gmail.com"更改为新的smtp转发主机。