myBtn.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                if(ContextCompat.checkSelfPermission(MainActivity.this,
                        Manifest.permission.READ_PHONE_STATE) == PackageManager.PERMISSION_GRANTED)
                {} else {
                    requestReadPhonePermission();
                }
            };// move the things you do with the telephony in the callback;
         }

@Override
public void onRequestPermissionsResult(int requestCode,
                                       String permissions[], int[] grantResults) {
    switch (requestCode) {
        case  Phone_State_Permission_Code: {

          // If request is cancelled, the result arrays are empty.
          if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                // permission was granted, yay! Do the
                // contacts-related task you need to do.
                  TelephonyManager tm=(TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);

                String IMEInum;
                IMEInum=tm.getDeviceId();
                IMEI.setText("IMEI: "+IMEInum);


                String lineNum = tm.getLine1Number();
                Linenum.setText("Line number: "+lineNum);

                int phoneType=tm.getPhoneType();
                switch (phoneType)
                {
                    case (TelephonyManager.PHONE_TYPE_CDMA):
                        Phonetype.setText("Phone type: CDMA");
                        break;
                    case (TelephonyManager.PHONE_TYPE_GSM):
                        Phonetype.setText("Phone type: GSM");
                        break;
                    case (TelephonyManager.PHONE_TYPE_NONE):
                        Phonetype.setText("Phone type: NONE");
                        break;
                }

                int CallState = tm.getCallState();
                switch (CallState) {
                    case TelephonyManager.CALL_STATE_IDLE:
                        Call.setText("CALL STATE : IDLE");
                        break;
                    case TelephonyManager.CALL_STATE_OFFHOOK:
                        Call.setText("CALL STATE : OFFHOOK");
                        break;
                    case TelephonyManager.CALL_STATE_RINGING:
                        Call.setText("CALL STATE : RINGING");
                        break;
                }

                int SIMState=tm.getSimState();
                switch(SIMState)
                {
                    case TelephonyManager.SIM_STATE_ABSENT :
                        Sim.setText("SIM state: ABSENT");
                        break;
                    case TelephonyManager.SIM_STATE_NETWORK_LOCKED :
                        Sim.setText("SIM state: NETWORK LOCKED");
                        break;
                    case TelephonyManager.SIM_STATE_PIN_REQUIRED :
                        Sim.setText("SIM state: PIN REQUIRED");
                        break;
                    case TelephonyManager.SIM_STATE_PUK_REQUIRED :
                        Sim.setText("SIM state: PUK REQUIRED");
                        break;
                    case TelephonyManager.SIM_STATE_READY :
                        Sim.setText("SIM state: READY");
                        break;
                    case TelephonyManager.SIM_STATE_UNKNOWN :
                        Sim.setText("SIM state: UNKNOWN");
                        break;

                }

            } else {

                // permission denied, boo! Disable the
                // functionality that depends on this permission.
                //handle the situation if the permission was denied;
            }
            return;
        }

        // other 'case' lines to check for other
        // permissions this app might request
    }
}