通过JavaMail API在Android中发送电子邮件而无需用户干预（无意图）

为此，我使用了以下代码：

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;
  }



}

我已经添加了必要的罐子。i、 e

（1）mail.jar

（2）激活.jar

（3）附加的.jar

但当我在Eclipse IDE中运行它时，LogCat上会显示以下错误消息：

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)

---

它甚至没有在手机上运行，我还在清单文件中添加了互联网权限。有谁能告诉我这里有什么问题吗？

我从您的

LogCat

问题中了解到的很多信息都在代码片段中：-

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

---

您到底想在邮件中附加什么？

您应该尝试

m.addAttachment（“/mnt/sdcard/filelocation”）

或者更好：

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

此外，请检查您是否已在清单中添加了以下权限：

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


您是否获得了必要的外部存储许可？对不起，我是新来的。请详细说明您必须在清单中获取权限。我现在添加了此权限。您能告诉我如何放置路径吗？例如，假设我需要发送名为“ppp.jpg”的图像，请告诉我如何指定其路径名。它是像/sdcard/ppp.jpg还是/E:/ppp.jpd或/SD Card/ppp.jpgEnvironment.getExternalStorageDirectory（）.getAbsolutePath（）+File.separator+“ppp.jpg”；这是一个音频文件。我甚至试着在手机上运行它，但它不工作，我想我没有指定确切的文件位置。可以给我你的gmail id吗？我需要再问几件事。我的是moin18@gmail.comI你补充道，你收到请求了吗，我的请求是harryb87@gmail.comi没有收到请求，但我刚刚给你发了一封电子邮件。我用了这封。它工作了，但现在如果我在应用程序中再次运行它，它不会执行任何操作。gmail是否使用阻止该应用程序？不知道为什么现在不允许发送任何电子邮件。即使没有错误，我现在也添加了此权限。您能告诉我如何放置路径吗？例如，假设我需要发送名为“ppp.jpg”的图像，请告诉我如何指定其路径名。是像/sdcard/ppp.jpg还是/E:/ppp.jpd或/SD Card/ppp.jpgdid您是这样尝试的：
Environment.getExternalStorageDirectory（）.getAbsolutePath（）+File.separator+“ppp.jpg”
？是的，我也尝试过，但仍然不起作用。。我还尝试删除addAttachment功能。我想可能是它不允许我做发送邮件的操作。我认为问题出在其他地方，我是这样使用它的，m.addAttachment（Environment.getExternalStorageDirectory（）.getAbsolutePath（）+File.separator+“ppp.jpg”）；不知道问题出在哪里你可以不带附件发送吗？？
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />