Firebase在Android中加入数据 [英] Firebase join data in Android
本文介绍了Firebase在Android中加入数据的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
学校名称
查询到类
只知道保护键的数据 G1
。我知道它可以在两个不同的调用完成,但我只是在一个调用服务器的时候这样做。 是否有可能?
学校
学校:
schoolKey1:
名称:School One
schoolKey2:
名称:School Two
课程
<$ p $ 类别:
someKey1:
名称:Class One
school:schoolKey1
guard:g1
警卫
警卫:
g1:
name:Pipoy Pat
解决方案
可能已经太晚了,但是您需要按照文档这里。
类似于:
var ref = new Firebase(https ://myApp.firebaseio.com/);
获取类
ref.child(classes)。addChildEventListener(new ChildEventListener(){
@Override
public void onChildAdded(DataSnapshot snapshot,String previousChildKey){
//获得学校关键字
字符串schoolKey = snapshot.getKey();
//从关键字$ b $获得学校名称ref.child(schools /+ schoolKey +/name\").addListenerForSingleValueEvent(new ValueEventListener(){
@Override
public void onDataChange(DataSnapshot snapshot){
System.out.println(是+ snapshot.getValue());
}
@Override
public void onCancelled(FirebaseError firebaseError){
//现在忽略
}
});
}
});
I'm try to join three data using Firebase. I want to retrieve the the school name
querying to classes
data knowing only guard key which is g1
. I know it can be done in two separate calls, but I'm trying to do it in just one call to the server.
Is it somewhat possible?
Schools
schools :
schoolKey1 :
name: School One
schoolKey2 :
name: School Two
Classes
classes :
someKey1 :
name: Class One
school : schoolKey1
guard : g1
Guard
guards :
g1 :
name: Pipoy Pat
解决方案
It might be too late but you would need to follow the documentation here.
something like:
var ref = new Firebase("https://myApp.firebaseio.com/");
// fetch classes
ref.child("classes").addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(DataSnapshot snapshot, String previousChildKey) {
//get school key
String schoolKey = snapshot.getKey();
//get school name from key
ref.child("schools/" + schoolKey + "/name").addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot snapshot) {
System.out.println("The school name is " + snapshot.getValue());
}
@Override
public void onCancelled(FirebaseError firebaseError) {
// ignore for now
}
});
}
});
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