Java 从具有另一个对象arraylist属性的对象的arraylist获取值

对于我的大学项目，我正在尝试实现一个分区回收视图，分区标题为日期，约会列表为内容，在每一行约会中，我想显示一些字段，我在其中创建了apnmntDetails类，如下所示：

public class apnmtDetails {
private String BarberName;
private String Barbershop;
private String ServiceName;
private String ServiceType;
private String Servicestatus;
private String ServicePrice;
private String ServiceTime;

public apnmtDetails(String barberName, String barbershop,
                    String serviceName, String serviceType,
                    String servicestatus, String servicePrice,
                    String serviceTime) {
    BarberName = barberName;
    Barbershop = barbershop;
    ServiceName = serviceName;
    ServiceType = serviceType;
    Servicestatus = servicestatus;
    ServicePrice = servicePrice;
    ServiceTime = serviceTime;
}

public String getBarberName() {
    return BarberName;
}

public void setBarberName(String barberName) {
    BarberName = barberName;
}

public String getBarbershop() {
    return Barbershop;
}

public void setBarbershop(String barbershop) {
    Barbershop = barbershop;
}

public String getServiceName() {
    return ServiceName;
}

public void setServiceName(String serviceName) {
    ServiceName = serviceName;
}

public String getServiceType() {
    return ServiceType;
}

public void setServiceType(String serviceType) {
    ServiceType = serviceType;
}

public String getServicestatus() {
    return Servicestatus;
}

public void setServicestatus(String servicestatus) {
    Servicestatus = servicestatus;
}

public String getServicePrice() {
    return ServicePrice;
}

public void setServicePrice(String servicePrice) {
    ServicePrice = servicePrice;
}

public String getServiceTime() {
    return ServiceTime;
}

public void setServiceTime(String serviceTime) {
    ServiceTime = serviceTime;
}

@Override
public String toString() {
    return "apnmtDetails{" +
            "BarberName='" + BarberName + '\'' +
            ", Barbershop='" + Barbershop + '\'' +
            ", ServiceName='" + ServiceName + '\'' +
            ", ServiceType='" + ServiceType + '\'' +
            ", Servicestatus='" + Servicestatus + '\'' +
            ", ServicePrice='" + ServicePrice + '\'' +
            ", ServiceTime='" + ServiceTime + '\'' +
            '}';
}}

之后，我创建了一个section类，它保存sectionName和sectionItem字段，其中sectionItem是apnmntDetails类的arraylist，代码如下：

public class Section {

private String SectionName;
private ArrayList<apnmtDetails> SectionItem;

public Section(String sectionName, ArrayList<apnmtDetails> sectionItem) {
    SectionName = sectionName;
    SectionItem = sectionItem;
}

public String getSectionName() {
    return SectionName;
}

public void setSectionName(String sectionName) {
    SectionName = sectionName;
}

public ArrayList<apnmtDetails> getSectionItem() {
    return SectionItem;
}

public void setSectionItem(ArrayList<apnmtDetails> sectionItem) {

    this.SectionItem.addAll(sectionItem);
}

@Override
public String toString() {
    return "Section{" +
            "SectionName='" + SectionName + '\'' +
            ", SectionItem=" + SectionItem +
            '}';
}}

firebase不是问题，因为该值已正确检索，如带有apnmntList标记的logcat中所示，但在使用servicelist arraylist打印该值时，该值未显示

---

我对Java还是有点陌生和陌生，因此，如果有人能帮我指出我的错误，我将不胜感激

您应该调用

sectionList.add（newsection（document.getString（“date”），apnmntList））内部onComplete（）回调方法。因为这是一个回调方法，所以在回调代码块之后，该方法被挂起，控件跳转以执行代码。在for循环之前，还应该初始化apnmntList，因为必须为每个部分保存新列表。
我已经对onComplete（）方法进行了更改，请看一下：

@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
    apnmntList = new ArrayList();
    for (DocumentSnapshot querysnapshot: task.getResult()){
        apnmtDetails details = new apnmtDetails(querysnapshot.getString("barber"),
                querysnapshot.getString("barber"),
                querysnapshot.getString("name"),
                querysnapshot.getString("type"),
                querysnapshot.getString("status"),
                querysnapshot.getString("price"),
                querysnapshot.getString("time slot"));

        apnmntList.add(details);
        Log.i("apnmntList", apnmntList.toString());

    }
    sectionList.add(new Section(document.getString("date"),apnmntList));
}

@覆盖
未完成的公共void（@NonNull任务）{
apnmntList=newarraylist（）；
对于（DocumentSnapshot querysnapshot:task.getResult（））{
apnmtDetails details=新的apnmtDetails（querysnapshot.getString（“barber”），
querysnapshot.getString（“理发师”），
querysnapshot.getString（“名称”），
querysnapshot.getString（“类型”），
querysnapshot.getString（“状态”），
querysnapshot.getString（“价格”），
getString（“时隙”）；
apnmntList.add（详细信息）；
Log.i（“apnntlist”，apnntlist.toString（））；
}
sectionList.add（新的部分（document.getString（“日期”），apnmntList））；
}
您好，先生，我尝试实施您建议的修复方案，当我将logcat放入for循环时，我可以打印serviceList，但当我尝试在onComplete外部打印时，结果是空的，我如何解决这个问题？它在onComplete（）内部正确打印吗？请看，回调方法类似于异步过程，所以您不应该在onComplete之外准备sectionList。好的，先生，非常感谢您的帮助
2021-03-04 14:57:06.748 4678-4678/com.example.homebarberv1 I/sectionList: Section{SectionName='4/AUG/2021', SectionItem=[]}
2021-03-04 14:57:07.029 4678-4678/com.example.homebarberv1 I/apnmntList: [apnmtDetails{BarberName='vAN7LYKoddRX2cQlogQtStOueKt2', Barbershop='vAN7LYKoddRX2cQlogQtStOueKt2', ServiceName='normal cut', ServiceType='Normal', Servicestatus='On hold', ServicePrice='4', ServiceTime='07:00 to 07:30'}]

@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
    apnmntList = new ArrayList();
    for (DocumentSnapshot querysnapshot: task.getResult()){
        apnmtDetails details = new apnmtDetails(querysnapshot.getString("barber"),
                querysnapshot.getString("barber"),
                querysnapshot.getString("name"),
                querysnapshot.getString("type"),
                querysnapshot.getString("status"),
                querysnapshot.getString("price"),
                querysnapshot.getString("time slot"));

        apnmntList.add(details);
        Log.i("apnmntList", apnmntList.toString());

    }
    sectionList.add(new Section(document.getString("date"),apnmntList));
}