<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.sendreadsmsexample">

    <uses-permission android:name="android.permission.SEND_SMS" />
    <uses-permission android:name="android.permission.READ_SMS" />
    <uses-permission android:name="android.permission.RECEIVE_SMS" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".ManMess"
            android:label="Manage Messages"
            android:parentActivityName=".MainActivity"></activity>
        <activity android:name=".ManKeys"
            android:label="Manage Keys"
            android:parentActivityName=".MainActivity"/>
        <activity android:name=".About"
            android:label="About"
            android:parentActivityName=".MainActivity"/>
        <activity android:name=".MainActivity" android:windowSoftInputMode="adjustPan" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <receiver android:name=".SmsBroadcastReceiver">
            <intent-filter>
                <action android:name="android.provider.Telephony.SMS_RECEIVED" />
            </intent-filter>
        </receiver>

        <service android:name=".MessageService"
            android:enabled="true"/>

    </application>

</manifest>

package com.example.sendreadsmsexample;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.SmsMessage;
import android.text.method.ScrollingMovementMethod;
import android.widget.TextView;
import android.widget.Toast;

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;


public class SmsBroadcastReceiver extends BroadcastReceiver
{
    @Override
    public void onReceive(Context context, Intent intent)
    {
        MainActivity mainActivity = new MainActivity();
        StringManager stringManager = new StringManager();
        MessageLogger messageLogger = new MessageLogger();
        KeyManager keyManager = new KeyManager();

        if(intent.getAction().equals("android.provider.Telephony.SMS_RECEIVED"))
        {
            Bundle bundle = intent.getExtras();
            SmsMessage[] msgs = null;
            String msg_from = "";
            String msgBody = "";

            if (bundle != null)
            {

                try
                {
                    Object[] pdus = (Object[]) bundle.get("pdus");

                    msgs = new SmsMessage[pdus.length];

                    for(int i=0; i<msgs.length; i++)
                    {
                        msgs[i] = SmsMessage.createFromPdu((byte[])pdus[i]);
                        msg_from = msgs[i].getOriginatingAddress();
                        msgBody = msgs[i].getMessageBody();

                        if (MainActivity.mThis != null )
                        {
                            if( stringManager.isKey(msgBody) && keyManager.hasKey(msg_from, context) == false )
                            {
                                Toast.makeText(context,"Recieved key piece: " + stringManager.getKeyNumber(msgBody) + " from " + msg_from + ".", Toast.LENGTH_LONG).show();
                                keyManager.addKeyEntry(msg_from, msgBody, context);
                                if( keyManager.hasKey(msg_from, context) )
                                {
                                    Toast.makeText(context,"A secure link has been established! You can now send encrypted messages to " + msg_from + ".", Toast.LENGTH_LONG).show();
                                }
                            }
                            else
                            {
                                ((TextView) MainActivity.mThis.findViewById(R.id.txtFrom)).setText("Sender: " + msg_from + " | Recieved Message Packet # " + stringManager.getNumber(msgBody));
                                messageLogger.addEntry(msgBody, msg_from, context);

                                if(messageLogger.gotMessageByID(msg_from,stringManager.getNumberID(msgBody),context))
                                {
                                    FileManager fileManager = new FileManager();
                                    MessageHistory messageHistory = new MessageHistory(msg_from, context);
                                    int ID = stringManager.getNumberID(msgBody);
                                    RSAUtil rsa = new RSAUtil();

                                    String text = "";

                                    text = messageLogger.getMessageByID(msg_from, ID, context);
                                    messageHistory.addEntry(text);
                                    String[] entries = messageHistory.getEntries();

                                    for(int j = 0; j < entries.length; j++)
                                    {
                                        try
                                        {
                                            entries[j] = "> " + rsa.decrypt(entries[j], fileManager.getContent("myPrivKey.txt", context)) + "\n";
                                        }
                                        catch (IllegalBlockSizeException e)
                                        {
                                            e.printStackTrace();
                                        }
                                        catch (InvalidKeyException e)
                                        {
                                            e.printStackTrace();
                                        }
                                        catch (BadPaddingException e)
                                        {
                                            e.printStackTrace();
                                        }
                                        catch (NoSuchAlgorithmException e)
                                        {
                                            e.printStackTrace();
                                        }
                                        catch (NoSuchPaddingException e)
                                        {
                                            e.printStackTrace();
                                        }
                                    }
                                    ((TextView) MainActivity.mThis.findViewById(R.id.txtFull)).setMovementMethod(new ScrollingMovementMethod());
                                    ((TextView) MainActivity.mThis.findViewById(R.id.txtFull)).setText(stringManager.unite(entries));
                                }
                            }
                        }
                    }
                }
                catch(Exception e)
                {

                }
            }
        }
    }
}