在时间戳之间从Firebase检索数据 [英] Retrieve Data from Firebase between timestamps

问题描述

我想在两个时间戳之间从FIREBASE检索数据，并且还附加了我的实时数据库Pic. 我想在日期和价格之间绘制图表.我正在制作一个应用程序，该应用程序显示商店的所有者根据时间(天，月或年)的销售情况，并通过添加价格child来显示总价格.我该怎么办?

I want to retrieve data from FIREBASE between two Timestamps and I also attached my realtimedatabase Pic. I want to make a graph between date and price .I am making an app which shows owner of store how's its sales going according to time(day,month or year) and Also show total price by adding price child . how can i do that?

推荐答案

要解决此问题，请使用以下代码:

To solve this, please use the following code:

String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
Query query = rootRef.child("User").child(uid).child("M3").orderByChild("timestamp").startAt(startTime).endAt(endTime);
ValueEventListener valueEventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            long price = ds.child("price").getValue(Long.class);
            Log.d(TAG, "price: " + long);
        }
    }

    @Override
    public void onCancelled(@NonNull DatabaseError databaseError) {
        Log.d(TAG, databaseError.getMessage());
    }
};
query.addListenerForSingleValueEvent(valueEventListener);

其中startTime是您要开始查询的时间戳，而endTime是您要结束查询的时间戳.

In which startTime is the timestamp from which you want to start query and endTime is the timestamp where you end the query.

这篇关于在时间戳之间从Firebase检索数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！