用这些优化发布我的应用程序之后；

minifyEnabled true
shrinkResources true
useProguard true

firebase将campaignmodel类中的日历代码视为一个节点，并将其作为“c”添加到数据中，其中包含所有当前时间的详细信息。我已经排除了使用proguard的所有类模型：

-keepclassmembers class com.tubevibe.android.models.CampaignModel {*;}
-keepclassmembers class com.tubevibe.android.models.UserModel {*;}

这个节点c导致我的应用程序在从实时数据库获取数据时崩溃。有什么方法可以阻止在日历中插入此节点？
这是我的竞选模式

package com.tubevibe.android.models;

import androidx.annotation.Keep;
import java.util.Calendar;

@Keep
public class CampaignModel {
    private String id;
    private String idNo;
    private String videoUrl;
    private String viewsNeeded;
    private String totalCost;
    private String active;
    private String timeRequired;
    private Long postingDate;

    Calendar c = Calendar.getInstance();
    int utcOffset = c.get(Calendar.ZONE_OFFSET) + c.get(Calendar.DST_OFFSET);

    public CampaignModel() {
    }

    public CampaignModel(String id, String idNo, String videoUrl,
                         String viewsNeeded,
                         String totalCost, String active, String timeRequired) {
        this.id = id;
        this.idNo = idNo;
        this.videoUrl = videoUrl;
        this.viewsNeeded = viewsNeeded;
        this.totalCost = totalCost;
        this.active = active;
        this.timeRequired = timeRequired;
        this.postingDate = c.getTimeInMillis() - utcOffset;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getIdNo() {
        return idNo;
    }

    public void setIdNo(String idNo) {
        this.idNo = idNo;
    }

    public String getViewsNeeded() {
        return viewsNeeded;
    }

    public void setViewsNeeded(String viewsNeeded) {
        this.viewsNeeded = viewsNeeded;
    }

    public String getTotalCost() {
        return totalCost;
    }

    public void setTotalCost(String totalCost) {
        this.totalCost = totalCost;
    }

    public String getTimeRequired() {
        return timeRequired;
    }

    public void setTimeRequired(String timeRequired) {
        this.timeRequired = timeRequired;
    }

    public String getVideoUrl() {
        return videoUrl;
    }

    public void setVideoUrl(String videoUrl) {
        this.videoUrl = videoUrl;
    }

    public Long getPostingDate() {
        return postingDate;
    }

    public void setPostingDate(Long postingDate) {
        this.postingDate = postingDate;
    }

    public String getActive() {
        return active;
    }

    public void setActive(String active) {
        this.active = active;
    } 
}