保存和读取 Integer Firestore Android

我正在尝试为我的 Android 游戏创建一个简单的 Stats 活动。我正在使用新的 Firestore 数据库。我已经能够将文档保存到我的Firestore数据库中，其中包含总分，最近得分，平均得分，总游戏数和高分，但是当我尝试从数据库中读回数据时，它会返回空值。

public void readFromDB(){
    statsDoc.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
        @Override
        public void onSuccess(DocumentSnapshot documentSnapshot) {
            if(documentSnapshot.exists()){
                UserData userdata = documentSnapshot.toObject(UserData.class);
            }
        }

我的用户数据类：

/* Copyright statement */

package com.squidstudios.android.balloonpopper.utils;

import com.google.firebase.database.IgnoreExtraProperties;

/**
 * UserData.java
 *
 * This class represents a single user's data including username, email, number of points earned,
 * a saved state of their progress towards earning a single point, and their password.
 */
@IgnoreExtraProperties
public class UserData {
    public String email;
    public int total_points;

public int avg_score;
public int high_score;
public int total_games;
public int prev_score;

public UserData() {
    // Default constructor required for calls to DataSnapshot.getValue(UserData.class)
}


public int getTotal_games() {
    return total_games;
}

public void setTotal_games(int total_games) {
    this.total_games = total_games;
}

public int getTotal_points() {
    return total_points;
}

public void setTotal_points(int total_points) {
    this.total_points = total_points;
}

public int getAvg_score() {
    return avg_score;
}

public void setAvg_score(int avg_score) {
    this.avg_score = avg_score;
}

public int getHigh_score() {
    return high_score;
}

public void setHigh_score(int high_score) {
    this.high_score = high_score;
}


public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

public int getPrev_score() {
    return prev_score;
}

public void setPrev_score(int prev_score) {
    this.prev_score = prev_score;
}

}

当我用字符串测试它时，它工作正常，但由于某种原因整数不起作用。提前致谢！