Firebase数据库-从数据库检索数据 [英] Firebase database - Retrieve data from database

问题描述

我是新的firebase开发人员，正在开发使用firebase数据库的android应用. 这是我数据库的一部分.

I am new firebase developer, a am developing an android app, that using firebase database. This is a part my database.

这是我的模型课:

public class Exam {
    private String id;
    private int subject;
    private String school;
    private Long examineDate;
    private int likeCount;
    private HashMap<String,Object> timeStampSubmit;
    public Exam(){};
    public Exam(String id, int subject, String school, Long examineDate, int likeCount) {
        this.id = id;
        this.subject = subject;
        this.school = school;
        this.examineDate = examineDate;
        this.likeCount = likeCount;
        HashMap<String, Object> timestampNowObject = new HashMap<String,Object>();
        timestampNowObject.put(Constant.FIREBASE_PROPERTY_TIMESTAMP, ServerValue.TIMESTAMP);
        this.timeStampSubmit = timestampNowObject;
    }
}

我想从数据库中获取数据并将其解析到Exam对象.

I want to get and parse data from my database to a Exam object.

您能给我建议还是有什么想法吗?

Could you give me suggestion or have any idea ?

推荐答案

您已阅读本指南-在Android上检索数据吗?

使用ValueEventListener

ValueEventListener examListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        Exam exam = dataSnapshot.getValue(Exam.class);
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
    }
};
ref.addValueEventListener(examListener);

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