package com.broad.sowmy.blockingcall;

import android.content.Context;
import android.content.SharedPreferences;
import android.media.AudioManager;
import android.preference.PreferenceManager;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;
import android.widget.Toast;

import java.lang.reflect.Method;

import com.android.internal.telephony.ITelephony;
/**
 * Created by sowmy on 24-10-2016.
 */

public class PhoneCallStateListener extends PhoneStateListener {

    private Context context;
    String block_num;
   SharedPreferences shared;

    public PhoneCallStateListener(Context context){
        this.context = context;
    }

    @Override
    public void onCallStateChanged(int state, String incomingNumber) {


        switch (state) {
            case TelephonyManager.CALL_STATE_RINGING:
                shared=context.getSharedPreferences("get",Context.MODE_PRIVATE);
block_num=shared.getString("number",null);
                AudioManager audioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
                audioManager.setStreamMute(AudioManager.STREAM_RING, true);
                TelephonyManager tm = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
                try {
                    Toast.makeText(context, block_num, Toast.LENGTH_SHORT).show();
                    Class clazz = Class.forName(tm.getClass().getName());
                    Method method = clazz.getDeclaredMethod("getITelephony");
                    method.setAccessible(true);
                    ITelephony telephonyService = (ITelephony) method.invoke(tm);

                    System.out.println("Call " + block_num);

                    if (incomingNumber.equalsIgnoreCase("+91" + block_num)) {

                        telephonyService = (ITelephony) method.invoke(tm);
                        telephonyService.silenceRinger();
                        System.out.println(" in  " + block_number);
                        telephonyService.endCall();
                    }
                } catch (Exception e) {
                    Toast.makeText(context, e.toString(), Toast.LENGTH_LONG).show();
                }
                //Turn OFF the mute
                audioManager.setStreamMute(AudioManager.STREAM_RING, false);
                break;
            case PhoneStateListener.LISTEN_CALL_STATE:

        }
        super.onCallStateChanged(state, incomingNumber);
    }

        }

package com.broad.sowmy.blockingcall;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;
import android.util.Log;
import android.widget.Toast;

/**
 * Created by sowmy on 24-10-2016.
 */

public class PhoneCallReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        TelephonyManager tm=(TelephonyManager)context.getSystemService(Context.TELEPHONY_SERVICE);
        PhoneCallStateListener phoneCallStateListener=new PhoneCallStateListener(context);
        tm.listen(phoneCallStateListener, PhoneStateListener.LISTEN_CALL_STATE);

    }
}

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


<uses-permission android:name="android.permission.CALL_PHONE"></uses-permission>
    <uses-permission android:name="android.permission.READ_PHONE_STATE">
    </uses-permission>
    <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"></uses-permission>
    <uses-permission android:name="android.permission.PROCESS_INCOMING_CALLS"></uses-permission>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <receiver android:name=".PhoneCallReceiver">
            <intent-filter>
                <action android:name="android.intent.action.PHONE_STATE"></action>
            </intent-filter>
        </receiver>
    </application>

</manifest>

package com.android.internal.telephony;

   public interface ITelephony {

      boolean endCall();

      void answerRingingCall();

      void silenceRinger();

  }