如何检查接收方是否接听电话？如果不是，则拨打数据库中给定的另一个号码

Question

我正在开发该应用程序，它可以一个一个地呼叫Google电子表格中给定的用户。我必须检查接收方是否接听电话，如果没有，则拨打下一个号码，否则播放预先录制的音频。

我已经开发了一个应用程序，该应用程序将在提供号码时拨打用户电话，现在我需要检查上述条件是否成立。

这是我的主要活动课程

public class MainActivity extends AppCompatActivity{

    private static final int REQUEST_CALL = 1;
    private EditText mEditTextNumber;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mEditTextNumber = findViewById(R.id.edit_text_number);
        ImageView imageCall = findViewById(R.id.image_call);

        imageCall.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                makePhoneCall();
            }
        });
    }

    private void makePhoneCall() {
        String number = mEditTextNumber.getText().toString();
        if (number.trim().length() > 0) {

            if (ContextCompat.checkSelfPermission(MainActivity.this,
                    Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(MainActivity.this,
                        new String[]{Manifest.permission.CALL_PHONE}, REQUEST_CALL);
            } else {
                String dial = "tel:" + number;
                startActivity(new Intent(Intent.ACTION_CALL, Uri.parse(dial)));
            }

        } else {
            Toast.makeText(MainActivity.this, "Enter Phone Number", Toast.LENGTH_SHORT).show();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == REQUEST_CALL) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                makePhoneCall();
            } else {
                Toast.makeText(this, "Permission DENIED", Toast.LENGTH_SHORT).show();
            }
        }
    }
}

我在某个地方找到了以下两个类，现在我应该如何在需要检查上述条件的主要活动中实现这两个类。

public class PhoneStateBroadcastReceiver extends BroadcastReceiver{

    @Override
    public void onReceive(Context context, Intent intent) {

        TelephonyManager telephonyManager = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
        telephonyManager.listen(new CustomPhoneStateListener(context), PhoneStateListener.LISTEN_CALL_STATE);

    }

}

public class CustomPhoneStateListener extends PhoneStateListener {

    //private static final String TAG = "PhoneStateChanged";
    Context context; //Context to make Toast if required
    public CustomPhoneStateListener(Context context) {
        super();
        this.context = context;
    }

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

        switch (state) {
            case TelephonyManager.CALL_STATE_IDLE:
                //when Idle i.e no call
                Toast.makeText(context, "Phone state Idle", Toast.LENGTH_LONG).show();
                break;
            case TelephonyManager.CALL_STATE_OFFHOOK:
                //when Off hook i.e in call
                //Make intent and start your service here
                Toast.makeText(context, "Phone state Off hook", Toast.LENGTH_LONG).show();
                break;
            case TelephonyManager.CALL_STATE_RINGING:
                //when Ringing
                Toast.makeText(context, "Phone state Ringing", Toast.LENGTH_LONG).show();
                break;
            default:
                break;
        }
    }
}