通过JavaMail API在Android中发送没有用户干预（无意图）的电子邮件

Question

for this i used the following code:

package moin.sms;

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; 

import android.os.Bundle;
import android.util.Log;
import android.widget.Button;


public class Mail extends javax.mail.Authenticator { 
  public String _user; 
  public 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 void 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 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; 
  } 
  public String[] getTo(){
      return _to;
  }

  public void setTo(String[] _to){
      this._to = _to;
  }

  public String getFrom(){
      return _from;
  }

  public void setFrom(String _from){
      this._from=_from;
  }

  public String getSubject(){
      return _subject;
  }

  public void setSubject(String _subject){
      this._subject=_subject;
  }



}

The activity calling this is as:

package moin.sms;



import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class GmailSendActivity extends Activity {


public void onCreate(Bundle icicle) { 
        super.onCreate(icicle); 
        setContentView(R.layout.main); 
        final TextView t1 = (TextView) findViewById(R.id.textView1);
        Button addImage = (Button) findViewById(R.id.button1); 
        addImage.setOnClickListener(new View.OnClickListener() { 
          public void onClick(View view) { 
            Mail m = new Mail();
            m._user = "**My Gmail ID**"; // username 
            m._pass = "**PASSWORD**"; // password

            String[] toArr = {"cistoran@live.com", "ivan017@gmail.com"}; 
            m.setTo(toArr); 
            m.setFrom("moin18@gmail.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(GmailSendActivity.this, "Email was sent successfully.", Toast.LENGTH_LONG).show(); 
              } else { 
                Toast.makeText(GmailSendActivity.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); 
            } 
          t1.setText("to :"+m.getTo().toString()+"* from: "+m.getFrom()+"* Sub: "+m.getSubject()+"* Messg: "+m.getBody());  
          } 

        }); 
      } 

}

I have already added the necessary jars. ie

(1) mail.jar

(2) activation.jar

(3) additional.jar

But when i run it in Eclipse IDE, following error message is displayed on The LogCat:

02-10 11:20:06.682: E/MailApp(435): Could not send email
02-10 11:20:06.682: E/MailApp(435): java.lang.NullPointerException
02-10 11:20:06.682: E/MailApp(435): at moin.sms.Mail.addAttachment(Mail.java:117)
02-10 11:20:06.682: E/MailApp(435): at moin.sms.GmailSendActivity$1.onClick(GmailSendActivity.java:34)
02-10 11:20:06.682: E/MailApp(435): at android.view.View.performClick(View.java:2408)
02-10 11:20:06.682: E/MailApp(435): at android.view.View$PerformClick.run(View.java:8816)
02-10 11:20:06.682: E/MailApp(435): at android.os.Handler.handleCallback(Handler.java:587)
02-10 11:20:06.682: E/MailApp(435): at android.os.Handler.dispatchMessage(Handler.java:92)
02-10 11:20:06.682: E/MailApp(435): at android.os.Looper.loop(Looper.java:123)
02-10 11:20:06.682: E/MailApp(435): at android.app.ActivityThread.main(ActivityThread.java:4627)
02-10 11:20:06.682: E/MailApp(435): at java.lang.reflect.Method.invokeNative(Native Method)
02-10 11:20:06.682: E/MailApp(435): at java.lang.reflect.Method.invoke(Method.java:521)
02-10 11:20:06.682: E/MailApp(435): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
02-10 11:20:06.682: E/MailApp(435): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
02-10 11:20:06.682: E/MailApp(435): at dalvik.system.NativeStart.main(Native Method)

It isn't even running on the mobile, i have also added the INTERNET permission in manifest file. Could anybody tell whats the problem here?

Answer 1

As much I got to know from your LogCat Issue is at code snippet:-

m.addAttachment("/sdcard/filelocation"); 

What exactly you are trying to attach with the mail?

Answer 2

You should try m.addAttachment("/mnt/sdcard/filelocation");

or even better:

Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + "myaudio.3gpp"

Also, check if you have added the following permission in the manifest:

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />