在新线程中启动课程

Question

（API级别12） 我已经在用户输入登录名和密码后实现了可以发送电子邮件的javax.mail。出于某种原因，我能够运行一次，并发送电子邮件。现在我得到一个错误NetworkOnMainThreadException。我环顾四周，我发现你可以像这样开始一个新的线程：

Thread onRun = new Thread{ 
     public void run() { 
      try{ 
       mail.send(); 
      }catch(Exception e) { 
      } 
     } 
    }; 
    onRun.Start(); 

但是，当我添加它时，应用程序崩溃。

有没有办法让这个类在一个新的线程中运行，所以我从来没有得到错误？ 感谢您的帮助。

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 = ""; // default smtp server 
_port = ""; // default smtp port 
_sport = ""; // 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", "false"); 
} 

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

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

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

public void setSMTP(String string) { 
    this._host = string; 
    } 

public void setPort(String string) { 
    this._port = string; 
    } 
public void setSPort(String string) { 
    this._sport = string; 
    } 

} 

Answer 1

作为例外的名称 - NetworkOnMainThreadException - 您无法在主线程上与网络进行交互。考虑使用AsyncTask或Service。 SDK文件夹内有一些示例代码。