查找datasnapshot firebase的子级的数据类型

Question

我在分析通过调用valueeventlistener获得的datasnapshot时遇到问题。由于某些原因，在查询数据库时，我选择使用它而不是ChildEventListener。

public Trainer(DataSnapshot dataSnapshot)
{
    for(DataSnapshot snapshot: dataSnapshot.getChildren())
    {
        Trainer trainer = snapshot.getValue(Trainer.class);

        name = trainer.name;
        civilNo = trainer.civilNo;
        email = trainer.email;
        age = trainer.age;
        phone = trainer.phone;
        gender = trainer.gender;
        password = trainer.password;
        carNo = trainer.carNo;
        places = trainer.places;
        vehicleType = trainer.vehicleType;
        languages = trainer.languages;
        rate = trainer.rate;
        price = trainer.price;
        contractType = trainer.contractType;
        spokenLanguage = trainer.spokenLanguage;
        trainingAreas=trainer.trainingAreas;
        hourPrice=trainer.hourPrice;
        contractPrice=trainer.contractPrice;
        trainingTime=trainer.trainingTime;
        key = snapshot.getRef().getKey();
    }
}

public class Trainers {

    private ArrayList<Trainer> trainers;

    public Trainers()
    {
        // Empty default constructor
    }

    public Trainers(DataSnapshot dataSnapshot)
    {
        trainers = new ArrayList<>();

        for(DataSnapshot snapshot: dataSnapshot.getChildren())
            trainers.add(new Trainer(snapshot));
    }

    public ArrayList<Trainer> getTrainers() {
        return trainers;
    }

    public void setTrainers(ArrayList<Trainer> trainers) {
        this.trainers = trainers;
    }
}

将生成一个错误,告诉我发生了转换错误：

我要求的是：

我想过确定传递的datasnapshots的子级是其他datasnapshots还是实际值，然后在此基础上使用if语句来进行正确的分析，但我不知道如何做到这一点。你能帮帮我吗？

Answer 1

您应该使用：

for(DataSnapshot snapshot: dataSnapshot.getChildren())
            trainers.add(snapshot.getValue(Trainer.class);
    }

在Public Trainers（DataSnapshot DataSnapshot)类中。