JavaMail: Java.awt.datatransfer.Transferable 不存在

Question

我不打算提出问题，但我没有解决这个问题的方法！
我在从 IMAP 服务器接收消息时遇到问题。
错误显示 "Caused by: java.lang.ClassNotFoundException: Didn't find class "java.awt.datatransfer.Transferable" on path..." 这是我的代码：

enter String test(){
    String all="";
    try{
        class Runner extends AsyncTask<Object, String, String> {
            @Override
            protected String doInBackground(Object... params) {
                Looper.prepare();
                String all ="";
                try{
                    Message[] msgs = ReceiveMail("imap.gmail.com","993","USER@gmail.com","PASS"); // After passing this line, error logging says error is in this line!
                    for(Message m: msgs){
                        all+=m.getSubject()+"\n"+m.getContent().toString()+"\n\n"; // Error shows here, but popups above
                    }
                    return all;
                }catch (Exception e){
                    e.printStackTrace();
                }
                Looper.loop();
                return all;
            }
        }
        Runner r = new Runner();
        all = r.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, this).get();
    }catch (Exception e){
        e.printStackTrace();
    }
    return all;
}
private Message[] ReceiveMail(String host,String port,String user,String pass){
    try{
        Properties props = new Properties();
        props.setProperty("mail.store.protocol", "imaps");
        props.setProperty("mail.imaps.host", host);
        props.setProperty("mail.imaps.port", port);
        props.setProperty("mail.imaps.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
        props.setProperty("mail.imaps.socketFactory.fallback", "false");
        Session imapSession = Session.getInstance(props);
        Store store = imapSession.getStore("imaps");
        store.connect(host, user, pass);
        Folder inbox = store.getFolder("Inbox");
        inbox.open(Folder.READ_ONLY);
        return inbox.getMessages();
    }catch (Exception e){
        e.printStackTrace();
        //log_all("ReceiveMail function: "+e.getMessage());
    }
    return null;
}

有什么问题？
注意当我不使用AsyncTask时出现错误"Network in main thread"。

解决方案:
下载 these 并将它们添加为库。
从 module settings.
的依赖项选项卡中删除 javax.* 这样就解决了。

Answer 1

因为它没有找到一些 class 也许您缺少外部 jar？

编辑

您可以使用 JavaMail API 来处理您的电子邮件任务。 JavaMail API 在 JavaEE 包中可用，其 jar 可供下载。遗憾的是，它不能直接在 Android 应用程序中使用，因为它使用与 Android 完全不兼容的 AWT 组件。（这就是您收到此错误的原因）

您可以在以下位置找到 JavaMail 的 Android 端口：http://code.google.com/p/javamail-android/

将 jar 添加到您的应用程序并使用 SMTP 方法

Answer 2

JavaMail API Reference Implementation version 1.5.5 and later have built in support for Android and include support for OAuth2。根据文档：

Android does not provide a Java Compatible runtime and so can't run the standard JavaMail distribution. Instead, a special version of JavaMail is available for Android. This special version of JavaMail depends on a special version of the JavaBeans Activation Framework.

You can try out this version by adding the following to your build.gradle file for your Android application:

 android {
     packagingOptions {
         pickFirst 'META-INF/LICENSE.txt' // picks the JavaMail license file
     }
 }

 repositories { 
     jcenter()
     maven {
         url "https://maven.java.net/content/groups/public/"
     }
 }

 dependencies {
     compile 'com.sun.mail:android-mail:1.5.6'
     compile 'com.sun.mail:android-activation:1.5.6'
 }

JavaMail: Java.awt.datatransfer.Transferable 不存在

JavaMail: Java.awt.datatransfer.Transferable doesn't exist

java

android

jakarta-mail