How to avoid an immediate notification In android app if the time you set has already passed?

Question

I wanted to send a local notification to user daily at 06.00 pm. but the problem is that if user opens the app after 06.00 pm. the Notification is getting repeated. how To solve this problem ?

Below is my Main Activity

public class MainActivity extends AppCompatActivity {

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


         Calendar calendar = Calendar.getInstance();


            calendar.set(Calendar.HOUR_OF_DAY, 02);
            calendar.set(Calendar.MINUTE, 54);
            calendar.set(Calendar.SECOND, 0);

            if(calendar.before(Calendar.getInstance())) {
                calendar.add(Calendar.DATE, 1);
            }



            Intent intent1 = new Intent(getApplicationContext(), AlarmReceiver.class);

            PendingIntent pendingIntent = PendingIntent.getBroadcast(MainActivity.this, 0,intent1, PendingIntent.FLAG_UPDATE_CURRENT);
            AlarmManager am = (AlarmManager) MainActivity.this.getSystemService(MainActivity.this.ALARM_SERVICE);
            am.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), AlarmManager.INTERVAL_DAY, pendingIntent);

Please help me.