[SOLVED] Firebase会为特定孩子返回空值，即使该孩子存在也是如此

Question

[EDIT]问题出在我的ComRec类上。 getKoil方法由于某些原因而无法使用。我使用studio生成了该方法，现在可以正常使用了。感谢帮助人员。[编辑]我有一个ComRec类，用于存储某些佣金值。 在计算器中，我输入了一些值并执行了一些操作，然后将其存储在Firebase中的特定用户下。 然后，我用ComRec对象的值创建一个pdf表。 但是我的问题是成员“ koil”即使在ComRec对象中也显示了null值。

public class ComRec {
private Double freeRation;
private Double npnsRice;
private Double npsRice;
private Double phhRice;
private Double aayRice;
private Double npnsWheat;
private Double phhWheat;
private Double aayWheat;
private Double atta;
private Double total;
private Double koil;
private Double sugar;
private Double totalCommission;

public ComRec(){

}

public ComRec(Double freeRation, Double npnsRice, Double npsRice, Double phhRice, Double aayRice, Double npnsWheat, Double phhWheat, Double aayWheat, Double atta, Double total, Double koil, Double sugar , Double totalCommission) {
    this.freeRation = freeRation;
    this.npnsRice = npnsRice;
    this.npsRice = npsRice;
    this.phhRice = phhRice;
    this.aayRice = aayRice;
    this.npnsWheat = npnsWheat;
    this.phhWheat = phhWheat;
    this.aayWheat = aayWheat;
    this.atta = atta;
    this.total = total;
    this.koil = koil;
    this.sugar = sugar;
    this.totalCommission = totalCommission;

}

用户类别

public class User {
private String UID;
private String ardNo;
private String email;
private String serialKey;
private String taluk;
private ComRec C;

public User(){

}

public User(String UID, String ardNo, String email, String serialKey,String taluk) {
    this.UID = UID;
    this.ardNo = ardNo;
    this.email = email;
    this.serialKey = serialKey;
    this.taluk = taluk;
    this.C = null;
}
public User(String UID, String ardNo, String email, String serialKey,String taluk,ComRec C) {
    this.UID = UID;
    this.ardNo = ardNo;
    this.email = email;
    this.serialKey = serialKey;
    this.taluk = taluk;
    this.C = C;
}

public String getUID() {
    return UID;
}

public void setUID(String UID) {
    this.UID = UID;
}

public String getArdNo() {
    return ardNo;
}

public void setArdNo(String ardNo) {
    this.ardNo = ardNo;
}

public String getEmail() {
    return email;
}

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

public String getSerialKey() {
    return serialKey;
}

public void setSerialKey(String serialKey) {
    this.serialKey = serialKey;
}

public String getTaluk() {
    return taluk;
}

public void setTaluk(String taluk) {
    this.taluk = taluk;
}

public ComRec getComRec() {
    return C;
}

public void setComRec(ComRec c) {
    C = c;
}

}

这是我的火力基地数据，您可以看到koil = 172.5：

其他所有成员均给出正确的值，但有误

这是通过从User类获取ComRec对象的方法

Answer 1

根据您的数据库结构，您可以使用它来获取Koil

  DatabaseReference reff = FirebaseDatabase.getInstance().getReference("User");
    reff.child(user.getUid()).child("comRec").addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            for(DataSnapshot snapshot:dataSnapshot.getChildren()){
                ComRec com = snapshot.getValue(ComRec.class);
                Double Koil = com.getkoil();
            }
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });