if (state.equals(TelephonyManager.EXTRA_STATE_RINGING)) {
Log.v("ranjith", "Entered in callstatelistener");

<!--  declare the permission -->
<uses-permission android:name="android.permission.READ_PHONE_STATE" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >

    <!-- Register your Broadcast receiver  -->
    <receiver android:name=".CallReceiver" android:enabled="true">
        <intent-filter>
                <action android:name="android.intent.action.PHONE_STATE" />
            </intent-filter>
       </receiver>

</application>

public class CallReceiver  extends BroadcastReceiver  {

static boolean isRinging = false;
static boolean isCallReceived = false;

@Override
public void onReceive(Context context, Intent intent) {
    // TODO Auto-generated method stub

    // Get the current Phone State
   String phoneState = intent.getStringExtra(TelephonyManager.EXTRA_STATE);

   if(phoneState == null)
       return;

   // If phone is "Rininging"
   if(phoneState.equals(TelephonyManager.EXTRA_STATE_RINGING))
   {
       isRinging = true;
   }

    // If an incoming call is received
   if(phoneState.equals(TelephonyManager.EXTRA_STATE_OFFHOOK))
   {
       isCallReceived = true;
   }

   // if phone is idle
   if (phoneState.equals(TelephonyManager.EXTRA_STATE_IDLE)){
       // detect call not received
       if(isRinging == true && isCallReceived == false){
           Toast.makeText(context, "Call was not received!", Toast.LENGTH_LONG).show();
       }
   }
}