How to send an email with a file attachment in Android

Folder_name is the name of the file in the Internal Storage of your phone. (ACTUALLY EXTERNAL_STORAGE). file_name is the name of the file you want to send.

private void ShareViaEmail(String folder_name, String file_name) {
    try {
        File root= Environment.getExternalStorageDirectory();
        String filelocation= root.getAbsolutePath() + folder_name + "/" + file_name;
        Intent intent = new Intent(Intent.ACTION_SENDTO);
        intent.setType("text/plain");
        String message="File to be shared is " + file_name + ".";
        intent.putExtra(Intent.EXTRA_SUBJECT, "Subject");
        intent.putExtra(Intent.EXTRA_STREAM, Uri.parse( "file://"+filelocation));
        intent.putExtra(Intent.EXTRA_TEXT, message);
        intent.setData(Uri.parse("mailto:[email protected]"));
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

        startActivity(intent);
    } catch(Exception e)  {
        System.out.println("is exception raises during sending mail"+e);
    }
}

SENDTO doesnt support attachment. I have added my answer using Provider to read the file information. Its in Kotlin.

fun shareFile(context: Context, filePath: File?, fileShareInfo: FileShareInfo) {

    val intentFileShare = Intent(Intent.ACTION_SEND)

    if (filePath!!.exists()) {
        intentFileShare.type = fileShareInfo.fileType
        val uri = FileProvider.getUriForFile(context, BuildConfig.APPLICATION_ID + ".provider", filePath)
        intentFileShare.putExtra(Intent.EXTRA_STREAM, uri)
        fileShareInfo.recipients?.let {
            intentFileShare.putExtra(Intent.EXTRA_EMAIL, fileShareInfo.recipients)
        }
        intentFileShare.putExtra(Intent.EXTRA_SUBJECT, fileShareInfo.shareSubjectText)
        fileShareInfo.shareExtraText?.let {
            intentFileShare.putExtra(Intent.EXTRA_TEXT, AppViewUtil.fromHtml(fileShareInfo.shareExtraText!!))
        }
        try {
            ContextCompat.startActivity(context, Intent.createChooser(intentFileShare, fileShareInfo.shareTitle), null)
        } catch (e: ActivityNotFoundException) {
            Toast.makeText(context, context.getString(R.string.sharing_no_app_found), Toast.LENGTH_LONG).show()
        }

    }
}

Use the below code to send a file within a email.

String filename="contacts_sid.vcf"; 
File filelocation = new File(Environment.getExternalStorageDirectory().getAbsolutePath(), filename);
Uri path = Uri.fromFile(filelocation); 
Intent emailIntent = new Intent(Intent.ACTION_SEND);
// set the type to 'email'
emailIntent .setType("vnd.android.cursor.dir/email");
String to[] = {"[email protected]"};
emailIntent .putExtra(Intent.EXTRA_EMAIL, to);
// the attachment
emailIntent .putExtra(Intent.EXTRA_STREAM, path);
// the mail subject
emailIntent .putExtra(Intent.EXTRA_SUBJECT, "Subject");
startActivity(Intent.createChooser(emailIntent , "Send email..."));

The example on the official Android site worked for me. All what is need it to add the

startActivity(Intent.createChooser(emailIntent , "Send email..."));

as done in Agarwal's answer