主应用程序.java

我对安卓系统比较陌生，我正在尝试创建一个在线音乐播放器应用程序。我使用了objectbox数据库的对象，我得到了以下错误。我不知道如何修复它。下面是我的代码

package lrandomdev.com.online.mp3player;
import android.app.Application;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;
import com.google.android.gms.ads.MobileAds;
import com.google.android.gms.analytics.GoogleAnalytics;
import com.google.android.gms.analytics.Tracker;
import com.google.firebase.FirebaseApp;
import com.google.gson.JsonObject;
import com.onesignal.OSNotification;
import com.onesignal.OSNotificationOpenResult;
import com.onesignal.OneSignal;
import org.json.JSONObject;
import io.objectbox.BoxStore;
import io.objectbox.annotation.Entity;
import lrandomdev.com.online.mp3player.helpers.ApiServices;
import lrandomdev.com.online.mp3player.helpers.RestClient;
import lrandomdev.com.online.mp3player.models.MyObjectBox;
import retrofit2.Callback;
import retrofit2.Response;
public class MainApplication extends Application {
    private BoxStore mBoxStore;
    private static MainApplication sApp;
    private static GoogleAnalytics sAnalytics;
    private static Tracker sTracker;
    @Override
    public void onCreate() {
        super.onCreate();
        sApp = MainApplication.this;
        FirebaseApp.initializeApp(getApplicationContext());
        OneSignal.startInit(this)
                .inFocusDisplaying(OneSignal.OSInFocusDisplayOption.Notification)
                .setNotificationOpenedHandler(new NotificationOpenHandler())
                .unsubscribeWhenNotificationsAreDisabled(true)
                .init();
        sAnalytics = GoogleAnalytics.getInstance(this);
        mBoxStore = MyObjectBox.builder().androidContext(MainApplication.this).build();
        ApiServices apiService = RestClient.getApiService();
        final retrofit2.Call<JsonObject> call = apiService.getAds();
        call.enqueue(new Callback<JsonObject>()

错误

android_app\app\src\main\java\lrandomdev\com\online\mp3player\MainApplication.java:29: error: cannot find symbol
import lrandomdev.com.online.mp3player.models.MyObjectBox;
                                             ^
  symbol:   class MyObjectBox
  location: package lrandomdev.com.online.mp3player.model