Problem when sending email from Android app

Question

I'm trying to send an email from my Android app directly to the recipient. But when I click send nothing happens. The success toast doesn't appear.

I used these classes: JSSEProvider, ByteArrayDatasource,MailSender

This is my main code:

Send_mail.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        if ("".equals(recipient_mail.getText().toString().trim())) {
            Toast.makeText(FirstActivity.this, "Enter Recipent Email ", Toast.LENGTH_SHORT).show();
        } else {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        MailSender sender = new MailSender(sender_mail.getText().toString(),
                                mail_password.getText().toString());
                        sender.sendMail(Subject.getText().toString(), Text.getText().toString(),
                                sender_mail.getText().toString(), recipient_mail.getText().toString());

                        Toast.makeText(context, "Success!", Toast.LENGTH_SHORT).show();
                    } catch (Exception e) {
                        Log.e("SendMail", e.getMessage(), e);
                    }
                }
            }).start();
        }
    }
});

This is my dialog activity:

Answer 1

You can not show a Toast message within a thread, you need to reach the main thread to achieve this. So, replace your toast message with this

runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                      Toast.makeText(FirstActivity.this, "Success!", Toast.LENGTH_SHORT).show();
                    }
                });