我是android的新手。我想构建一个应用程序来接收＆amp;从我自己的应用程序中读取电子邮件。我在这些链接的帮助下准备了我的代码。一些博客。
Retrieving all unread emails using javamail with POP3 protocol
https://buddhimawijeweera.wordpress.com/2011/02/09/sendreceiveemailsjava/
https://metoojava.wordpress.com/2010/03/21/java-code-to-receive-mail-using-javamailapi/
我已经工作了将近两个星期，但仍然应用程序没有显示收到的电子邮件。请帮我查找错误。或者你知道一个代码将Gmail应用程序与我的应用程序连接以接收电子邮件吗？非常感谢您对该应用程序的任何帮助。
MailReaderActivity.java（主要活动）
public class MailReaderActivity extends Activity{
Folder inbox;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}
public MailReaderActivity(){
Properties props = System.getProperties();
props.setProperty("mail.store.protocol", "imaps");
try {
Session session = Session.getDefaultInstance(props, null);
Store store;
store = session.getStore("imaps");
store.connect("imap.gmail.com","<user@gmail.com>","<password>");
inbox = store.getFolder("Inbox");
System.out.println("No of Unread Messages : " + inbox.getUnreadMessageCount());
inbox.open(Folder.READ_ONLY);
Message messages[] = inbox.search(new FlagTerm(new Flags(Flag.SEEN), false));
FetchProfile fp = new FetchProfile();
fp.add(FetchProfile.Item.ENVELOPE);
fp.add(FetchProfile.Item.CONTENT_INFO);
inbox.fetch(messages, fp);
try {
printAllMessages(messages);
inbox.close(true);
store.close();
} catch (Exception ex) {
System.out.println("Exception arise at the time of read mail");
ex.printStackTrace();
}
} catch (NoSuchProviderException e) {
e.printStackTrace();
System.exit(1);
} catch (MessagingException e) {
e.printStackTrace();
System.exit(2);
}
}
public void printAllMessages(Message[] msgs) throws Exception
{
for (int i = 0; i < msgs.length; i++)
{
System.out.println("MESSAGE #" + (i + 1) + ":");
printEnvelope(msgs[i]);
}
}
public void printEnvelope(Message message) throws Exception
{
Address[] a;
// FROM
if ((a = message.getFrom()) != null)
{
for (int j = 0; j < 2; j++)
{
System.out.println("FROM: " + a[j].toString());
}
}
// TO
if ((a = message.getRecipients(Message.RecipientType.TO)) != null)
{
for (int j = 0; j < 2; j++)
{
System.out.println("TO: " + a[j].toString());
}
}
String subject = message.getSubject();
Date receivedDate = message.getReceivedDate();
String content = message.getContent().toString();
System.out.println("Subject : " + subject);
System.out.println("Received Date : " + receivedDate.toString());
System.out.println("Content : " + content);
getContent(message);
}
public void getContent(Message msg)
{
try
{
String contentType = msg.getContentType();
System.out.println("Content Type : " + contentType);
Multipart mp = (Multipart) msg.getContent();
int count = mp.getCount();
for (int i = 0; i < count; i++)
{
dumpPart(mp.getBodyPart(i));
}
}
catch (Exception ex)
{
System.out.println("Exception arise at get Content");
ex.printStackTrace();
}
}
public void dumpPart(Part p) throws Exception
{
// Dump input stream ..
InputStream is = p.getInputStream();
// If "is" is not already buffered, wrap a BufferedInputStream
// around it.
if (!(is instanceof BufferedInputStream))
{
is = new BufferedInputStream(is);
}
int c;
System.out.println("Message : ");
while ((c = is.read()) != -1)
{
System.out.write(c);
}
}
public static void main(String args[])
{
new MailReaderActivity();
}
}
的Manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.AUTHENTICATE_ACCOUNTS" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MailReaderActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
Logcat
//01-19 13:09:00.554 8487-8487/com.example.dell.frfr E/Trace﹕ error opening trace file: No such file or directory (2)
01-19 13:09:00.812 8487-8487/com.example.dell.frfr E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.dell.frfr/com.example.dell.frfr.MailReaderActivity}: android.os.NetworkOnMainThreadException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2277)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2403)
at android.app.ActivityThread.access$600(ActivityThread.java:165)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1373)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5370)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1128)
at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
at java.net.InetAddress.getByName(InetAddress.java:289)
at java.net.InetSocketAddress.<init>(InetSocketAddress.java:105)
at java.net.InetSocketAddress.<init>(InetSocketAddress.java:90)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:321)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:237)
at com.sun.mail.iap.Protocol.<init>(Protocol.java:116)
at com.sun.mail.imap.protocol.IMAPProtocol.<init>(IMAPProtocol.java:115)
at com.sun.mail.imap.IMAPStore.newIMAPProtocol(IMAPStore.java:685)
at com.sun.mail.imap.IMAPStore.protocolConnect(IMAPStore.java:636)
at javax.mail.Service.connect(Service.java:295)
at javax.mail.Service.connect(Service.java:176)
at com.example.dell.frfr.MailReaderActivity.<init>(MailReaderActivity.java:53)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1319)
at android.app.Instrumentation.newActivity(Instrumentation.java:1123)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2268)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2403)
at android.app.ActivityThread.access$600(ActivityThread.java:165)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1373)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5370)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)
//
答案 0 :(得分：0)
我不知道您是否已经修复了这个错误，但如果我仍然回答它，它可能会帮助有类似问题的人。
在您的LogCat中。它说Caused by: android.os.NetworkOnMainThreadException
Android默认情况下不允许任何网络与应用程序的其余部分在同一个线程上。因此，为了解决这个问题，我们只需创建一个新线程来运行它。
替换：
public static void main(String args[])
{
new MailReaderActivity();
}
用这个：
public static void main(String args[])
{
Thread thread = new Thread() {
@Override
public void run() {
new MailReaderActivity();
}
};
thread.start();
}
答案 1 :(得分：0)
您应该使用AsyncTask异步执行网络线程。有关更多信息，请阅读the docs。