Question

我是FirebaseDatabase的新手，我在我的Android应用程序中使用以下数据库，我想收到 isStaff = true的关键值的用户的电子邮件但我没有得到如何浏览所有用户并找到它！

这是我的数据库

"users": {
        "EPcx2FzeI6U70DPxC3JyExweQvg1": {
            "email": "pizzeriapp101@gmail.com",
            "name": "Admin",
            "phone": "999999999",
            "profile_image": "https://www.livehappy.com/sites/default/files/styles/author/public/default_images/default_profile.png?itok=4-Un3euK",
            "security_level": "1",
            "user_id": "EPcx2FzeI6U70DPxC3JyExweQvg1",
            "isStaff": "true"
        },
        "RjEKX0O0aBZKIBv7XM4TNpTQT403": {
            "email": "kulkarnibharat018@gmail.com",
            "name": "Peter McKinnon",
            "phone": "9986922743",
            "profile_image": "https://firebasestorage.googleapis.com/v0/b/joes-pizzeria.appspot.com/o/images%2Fusers%2FRjEKX0O0aBZKIBv7XM4TNpTQT403%2Fprofile_image?alt=media&token=545f867b-c85c-40ec-b09d-d228da56309d",
            "security_level": "1",
            "user_id": "RjEKX0O0aBZKIBv7XM4TNpTQT403",
            "isStaff": "false"
        },
    "YSCVxPQKXLgfiJFCyNMS1P7BN2I3": {
            "email": "mrblackberryboy@gmail.com",
            "name": "S W",
            "phone": "99632587401",
            "profile_image": "https://firebasestorage.googleapis.com/v0/b/joes-pizzeria.appspot.com/o/images%2Fusers%2FYSCVxPQKXLgfiJFCyNMS1P7BN2I3%2Fprofile_image?alt=media&token=0beb92b5-a33a-478a-8795-7c972810d974",
            "security_level": "1",
            "user_id": "YSCVxPQKXLgfiJFCyNMS1P7BN2I3",
            "isStaff": "false"
        }

请帮忙！谢谢

Answer 1

要解决此问题，请使用以下代码：

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
Query query = rootRef.child("users").orderByChild("isStaff").equalsTo(true);
ValueEventListener eventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            String email = ds.child("email").getValue(String.class);
            Log.d("TAG", email);
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {}
};
query.addListenerForSingleValueEvent(eventListener);

Firebase数据库根据特定键值查询用户数据

1 个答案: