Alban Gashi Alban Gashi - 1 month ago 16
Android Question

Android Javamail Attachment throws java.lang.NullPointerException

Hi everybody I am trying to make an email sender app and the sending just emails works fine but when I try to add an attachment it says nullpointerexception

here's the error

W/System.err: java.lang.NullPointerException
W/System.err: at com.example.milingona.anew.MainActivity.addAttachment(MainActivity.java:120)
W/System.err: at com.example.milingona.anew.MainActivity.onActivityResult(MainActivity.java:96)
W/System.err: at android.app.Activity.dispatchActivityResult(Activity.java:5322)
W/System.err: at android.app.ActivityThread.deliverResults(ActivityThread.java:3363)
W/System.err: at android.app.ActivityThread.handleSendResult(ActivityThread.java:3410)
W/System.err: at android.app.ActivityThread.access$1100(ActivityThread.java:141)
W/System.err: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1304)
W/System.err: at android.os.Handler.dispatchMessage(Handler.java:99)
W/System.err: at android.os.Looper.loop(Looper.java:137)
W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5103)
W/System.err: at java.lang.reflect.Method.invokeNative(Native Method)
W/System.err: at java.lang.reflect.Method.invoke(Method.java:525)
W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
W/System.err: at dalvik.system.NativeStart.main(Native Method)


and here's the code

import android.Manifest;
import android.app.ProgressDialog;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.format.DateFormat;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import java.io.File;
import java.io.UnsupportedEncodingException;
import java.util.Date;
import java.util.Properties;

import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.mail.BodyPart;
import javax.mail.Message;
import javax.mail.MessagingException;
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;

public class MainActivity extends AppCompatActivity {

Button btn;
ImageView imageView;
String root;
String imageFolderPath;
String imageName;
Uri fileUri;

private static final String username = "use@gmail.com";
private static final String password = "*********";
private Multipart _multipart;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button) findViewById(R.id.captureImage);
imageView= (ImageView) findViewById(R.id.imageView);
if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[] { Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.ACCESS_NETWORK_STATE, Manifest.permission.INTERNET, Manifest.permission_group.STORAGE }, 0);
}
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
root = Environment.getExternalStorageDirectory()
+ "/ANew";

// Creating folders for Image
imageFolderPath = root + "/Images";
File imagesFolder = new File(imageFolderPath);
imagesFolder.mkdirs();
Date d = new Date();
CharSequence s = DateFormat.format("hh-mm-ss", d.getTime());
// Generating file name
imageName = "img-" + s + ".jpg";

// Creating image here

File image = new File(imageFolderPath, imageName);

fileUri = Uri.fromFile(image);

Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);

startActivityForResult(takePictureIntent, 1);
}
});

}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
try {
addAttachment(fileUri.getPath());
} catch (Exception e) {
e.printStackTrace();
}
sendMail("receiver@gmail.com","Subject","MESSAGE");
}
private void sendMail(String email, String subject, String messageBody) {
Session session = createSessionObject();

try {
Message message = createMessage(email, subject, messageBody, session);
new SendMailTask().execute(message);
} catch (MessagingException | UnsupportedEncodingException e) {
e.printStackTrace();

}
}

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);
}

private Message createMessage(String email, String subject, String messageBody, Session session) throws MessagingException, UnsupportedEncodingException {
Message message = new MimeMessage(session);
message.setFrom(new InternetAddress("user@gmail.com", "Alban Gashi"));
message.addRecipient(Message.RecipientType.TO, new InternetAddress(email, email));
message.setSubject(subject);
message.setText(messageBody);
return message;
}

private Session createSessionObject() {
Properties properties = new Properties();
properties.put("mail.smtp.auth", "true");
properties.put("mail.smtp.starttls.enable", "true");
properties.put("mail.smtp.host", "smtp.gmail.com");
properties.put("mail.smtp.port", "587");

return Session.getInstance(properties, new javax.mail.Authenticator() {
protected PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(username, password);
}
});
}

private class SendMailTask extends AsyncTask<Message, Void, Void> {
private ProgressDialog progressDialog;

@Override
protected void onPreExecute() {
super.onPreExecute();
progressDialog = ProgressDialog.show(MainActivity.this, "Please wait", "Sending mail", true, false);
}

@Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
progressDialog.dismiss();
}

@Override
protected Void doInBackground(Message... messages) {
try {
Transport.send(messages[0]);
} catch (MessagingException e) {
e.printStackTrace();
}
return null;
}
}
}


BTW I added the permissions in manifest

<uses-feature android:name="android.hardware.camera2"></uses-feature>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>

Answer

You are not initializing _multipart variable anywhere, therefore you get a NullPointerException when trying to access its method .addBodyPart on line 120 of your MainActivity.

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