Detect the end of an answered incoming call by user in android? (not declined)

In my android application, I have created a BroadcastReceiver that detects incoming call; my code is running very well. If there is an incoming call (EXTRA_STATE_RINGING), I can see my incommingNumber in the logcat, also when the user answered the call (EXTRA_STATE_OFFHOOK)

• I used shared preferences to store incoming number (String) in ringing state, then get it in Off HOOK state.

This is my code, it works perfectly:

 public class IncomingCallReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        
           String incomingNumber = null ;
          if (intent.getStringExtra(TelephonyManager.EXTRA_STATE).equals(TelephonyManager.EXTRA_STATE_RINGING)) 
          {
            // Ringing state
            // Phone number 
              incomingNumber = intent.getStringExtra(TelephonyManager.EXTRA_INCOMING_NUMBER);
             
              Log.i("test2", incomingNumber);
              
              SharedPreferences myPrefs = context.getSharedPreferences("myPrefs",Context.MODE_WORLD_WRITEABLE);
              SharedPreferences.Editor prefsEditor = myPrefs.edit();
              prefsEditor.putString("Incomingnumber", incomingNumber);
              //Not forgot to commit.
              prefsEditor.commit();

              
          } 
          
          else if  (intent.getStringExtra(TelephonyManager.EXTRA_STATE).equals(TelephonyManager.EXTRA_STATE_OFFHOOK)) 
          {
              //get the incoming number 
              SharedPreferences myPrefs = context.getSharedPreferences("myPrefs",Context.MODE_WORLD_READABLE);
              String incomNumber = myPrefs.getString("Incomingnumber", incomingNumber);
              
              // This code will execute when the call is answered
              
              Log.i("test2", incomNumber);
              Toast.makeText(context,incomNumber, Toast.LENGTH_LONG).show();
               
          }

BUT: My problem that my code can display a toast when the user just Accept the incoming call.

So, I need to know how I can detect the end of an answered the incoming call to do something else (display an alert dialog or launch an activity)

I've posted this here before- here's my class for detecting incoming calls start and end, outgoing calls start and end, and missed calls.

package com.gabesechan.android.reusable.receivers;

import java.util.Date;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;

public abstract class PhonecallReceiver extends BroadcastReceiver {

    //The receiver will be recreated whenever android feels like it.  We need a static variable to remember data between instantiations
    static PhonecallStartEndDetector listener;
    String outgoingSavedNumber;
    protected Context savedContext;


    @Override
    public void onReceive(Context context, Intent intent) {
        savedContext = context;
        if(listener == null){
            listener = new PhonecallStartEndDetector();
        }

        //We listen to two intents.  The new outgoing call only tells us of an outgoing call.  We use it to get the number.
        if (intent.getAction().equals("android.intent.action.NEW_OUTGOING_CALL")) {
            listener.setOutgoingNumber(intent.getExtras().getString("android.intent.extra.PHONE_NUMBER"));
            return;
        }

        //The other intent tells us the phone state changed.  Here we set a listener to deal with it
        TelephonyManager telephony = (TelephonyManager)context.getSystemService(Context.TELEPHONY_SERVICE); 
        telephony.listen(listener, PhoneStateListener.LISTEN_CALL_STATE);
    }

    //Derived classes should override these to respond to specific events of interest
    protected abstract void onIncomingCallStarted(String number, Date start);
    protected abstract void onOutgoingCallStarted(String number, Date start);
    protected abstract void onIncomingCallEnded(String number, Date start, Date end); 
    protected abstract void onOutgoingCallEnded(String number, Date start, Date end);
    protected abstract void onMissedCall(String number, Date start);

    //Deals with actual events
    public class PhonecallStartEndDetector extends PhoneStateListener {
        int lastState = TelephonyManager.CALL_STATE_IDLE;
        Date callStartTime;
        boolean isIncoming;
        String savedNumber;  //because the passed incoming is only valid in ringing

        public PhonecallStartEndDetector() {}

        //The outgoing number is only sent via a separate intent, so we need to store it out of band
        public void setOutgoingNumber(String number){
            savedNumber = number;
        }

        //Incoming call-  goes from IDLE to RINGING when it rings, to OFFHOOK when it's answered, to IDLE when its hung up
        //Outgoing call-  goes from IDLE to OFFHOOK when it dials out, to IDLE when hung up
        @Override
        public void onCallStateChanged(int state, String incomingNumber) {
            super.onCallStateChanged(state, incomingNumber);
            if(lastState == state){
                //No change, debounce extras
                return;
            }
            switch (state) {
                case TelephonyManager.CALL_STATE_RINGING:
                    isIncoming = true;
                    callStartTime = new Date();
                    savedNumber = incomingNumber;
                    onIncomingCallStarted(incomingNumber, callStartTime);
                    break;
                case TelephonyManager.CALL_STATE_OFFHOOK:
                    //Transition of ringing->offhook are pickups of incoming calls.  Nothing donw on them
                    if(lastState != TelephonyManager.CALL_STATE_RINGING){
                        isIncoming = false;
                        callStartTime = new Date();
                        onOutgoingCallStarted(savedNumber, callStartTime);                      
                    }
                    break;
                case TelephonyManager.CALL_STATE_IDLE:
                    //Went to idle-  this is the end of a call.  What type depends on previous state(s)
                    if(lastState == TelephonyManager.CALL_STATE_RINGING){
                        //Ring but no pickup-  a miss
                        onMissedCall(savedNumber, callStartTime);
                    }
                    else if(isIncoming){
                        onIncomingCallEnded(savedNumber, callStartTime, new Date());                        
                    }
                    else{
                        onOutgoingCallEnded(savedNumber, callStartTime, new Date());                                                
                    }
                    break;
            }
            lastState = state;
        }

    }



}