在android，使用JavaMail API发送邮件，而不使用默认的/内置的应用程序。

Question

我正在尝试做一个在android下发送电子邮件的应用程序。
如果我用

Intent emailIntent = new Intent(android.content.Intent.ACTION_SEND);

这将启动android内置的应用程序。我想要当点击按钮的时候直接发送邮件，而不使用这个应用程序。

Answer 1

在android使用JavaMail API发送电子邮件需要用到Gmail身份验证。
先创建一个简单的project

MailSenderActivity.java
YOUR PACKAGE;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
public class MailSenderActivity extends Activity {
   /** 当activity第一次创建的时候调用 */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       final Button send= (Button) this.findViewById(R.id.send);
        send.setOnClickListener(new View.OnClickListener() {
           public void onClick(View v) {
               try {
                      GMailSender sender= new GMailSender("[e-mail]", "password");
                    sender.sendMail("This is Subject",
                              "This is Body",
                              "[e-mail]",
                              "[e-mail]");
                  } catch (Exception e) {
                      Log.e("SendMail", e.getMessage(), e);
                  }
            }
       });
   }
}

GmailSender.java

YOUR PACKAGE;
import javax.activation.DataHandler;
  import javax.activation.DataSource;
  import javax.mail.Message;
  import javax.mail.PasswordAuthentication;
  import javax.mail.Session;
  import javax.mail.Transport;
  import javax.mail.internet.InternetAddress;
  import javax.mail.internet.MimeMessage;
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.security.Security;
  import java.util.Properties;
  public class GMailSender extends javax.mail.Authenticator {
      private String mailhost= "smtp.gmail.com";
      private String user;
      private String password;
      private Session session;
      static {
          Security.addProvider(new com.provider.JSSEProvider());
      }
     public GMailSender(String user, String password) {
          this.user= user;
          this.password= password;
          Properties props= new Properties();
           props.setProperty("mail.transport.protocol", "smtp");
           props.setProperty("mail.host", mailhost);
           props.put("mail.smtp.auth", "true");
           props.put("mail.smtp.port", "465");
           props.put("mail.smtp.socketFactory.port", "465");
           props.put("mail.smtp.socketFactory.class",
                  "javax.net.ssl.SSLSocketFactory");
           props.put("mail.smtp.socketFactory.fallback", "false");
           props.setProperty("mail.smtp.quitwait", "false");
           session= Session.getDefaultInstance(props, this);
      }
      protected PasswordAuthentication getPasswordAuthentication() {
          return new PasswordAuthentication(user, password);
      }
      public synchronized void sendMail(String subject, String body, String sender, String recipients) throws Exception {
          try{
       MimeMessage message= new MimeMessage(session);
          DataHandler handler= new DataHandler(new ByteArrayDataSource(body.getBytes(), "text/plain"));
           message.setSender(new InternetAddress(sender));
           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));
          Transport.send(message);
          }catch(Exception e){
       }
   }
      public class ByteArrayDataSource implements DataSource {
          private byte[] data;
          private String type;
          public ByteArrayDataSource(byte[] data, String type) {
              super();
              this.data= data;
              this.type= type;
          }
          public ByteArrayDataSource(byte[] data) {
              super();
              this.data= data;
          }
          public void setType(String type) {
              this.type= type;
          }
          public String getContentType() {
              if (type== null)
                  return "application/octet-stream";
              else
                 return type;
          }
          public InputStream getInputStream() throws IOException {
              return new ByteArrayInputStream(data);
          }
          public String getName() {
              return "ByteArrayDataSource";
          }
          public OutputStream getOutputStream() throws IOException {
              throw new IOException("Not Supported");
          }
      }
  }

JSSE Provider

import java.security.AccessController;
import java.security.Provider;
public final class JSSEProvider extends Provider {
   public JSSEProvider() {
       super("HarmonyJSSE", 1.0, "Harmony JSSE Provider");
       AccessController.doPrivileged(new java.security.PrivilegedAction<Void>() {
           public Void run() {
                put("SSLContext.TLS",                       "org.apache.harmony.xnet.provider.jsse.SSLContextImpl");
                put("Alg.Alias.SSLContext.TLSv1", "TLS");
                put("KeyManagerFactory.X509",                       "org.apache.harmony.xnet.provider.jsse.KeyManagerFactoryImpl");
                put("TrustManagerFactory.X509",                       "org.apache.harmony.xnet.provider.jsse.TrustManagerFactoryImpl");
               return null;
           }
       });
   }
}

对于你的android project，在下边的链接中发现了额外的3个jar文件（点击project-add external jars）
mail.jar
activation.jar
additionnal.jar
运行project，然后检查收件人邮件账户的邮件。
希望这个对你有帮助。