Writing array in Firebase android

Question

I am trying to write this to my Firebase

Parent

--0 : John

--1 : Tim

--2 : Sam

--3 : Ben

I am doing this

String[         


        

Answer 1

List sendingList = new ArrayList<>(Arrays.asList(SendingArray));

In case of any error, press Alt+Enter. It will correct it depending on you version of android studio

Answer 2

The .setValue() method needs a List rather than an Array.

The native types accepted by this method for the value correspond to the JSON types: Boolean, Long, Double, Map, String, Object, List, Object...

Firebase ref = new Firebase("<my-firebase-app>/names"):
String[] names = {"John","Tim","Sam","Ben"};
List nameList = new ArrayList<String>(Arrays.asList(names));
// Now set value with new nameList
ref.setValue(nameList);  

But, I recommend using a Map instead of a List. Rather than having an index based key (1,2,3...), you could use the name as the key so it's easier to retrieve.

Firebase ref = new Firebase("<my-firebase-app>/names"):
HashMap<String, String> names = new HashMap()<String, String>;
names.put("John", "John");
names.put("Tim", "Tim");
names.put("Sam", "Sam");
names.put("Ben", "Ben");
ref.setValue(names);

And now if you want to retrieve the data, you just need to know the name.

Firebase ref = new Firebase("<my-firebase-app>/names"):
Firebase johnRef = ref.child("john");
johnRef.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot snapshot) {
       System.out.println(snapshot.value); // the String "John"
    }
    @Override
    public void onCancelled(FirebaseError firebaseError) {

    }
});

Read the Firebase docs for more information.

Answer 3

I am not sure about Java, but for web application, you can use something as follows:

I wanted to create a reusable function to add/save any object under a root node (even if that has an array of data at any level within the object). So I came up with this. (I am not sure if conforms to the best practices, but it worked pretty smooth)

    SaveWholeData: function(sKey, oVal, bGenKey) {
        bGenKey = bGenKey === undefined ? true: bGenKey;
        var oOriginalProperty = angular.copy(oVal);
        for (var property in oVal) {
            if (oVal.hasOwnProperty(property) && oVal[property] instanceof Array) {
                console.log(property);
                oVal[property] = "$|$";
            }
        }
        var sOwnRef = SaveDataByKey(sKey, oVal, bGenKey);
        for (var property in oVal) {
            if (oVal.hasOwnProperty(property) && oVal[property] === "$|$") {
                oVal[property] = oOriginalProperty[property];
                var updatedReference = sOwnRef + "/" + property;
               SaveWholeData(updatedReference, oVal[property], false);
            }
        }
        return true;
    },
    SaveDataByKey: function(sKey, oVal, bGenKey) {
        if (bGenKey) {
            var newPostKey = firebase.database().ref(sKey).push().key;
            oVal.genKey = newPostKey;
            firebase.database().ref(sKey).child(newPostKey).set(oVal);
            return sKey + "/" + newPostKey;
        }else{
            firebase.database().ref(sKey).set(oVal);
            return sKey;
        }
    }

So to add new user under root users, you call:

SaveWholeData("users", oUserInfo, true);

and to update existing user:

SaveWholeData("users"+"/"+ oUserInfo.genKey, oUserInfo, true);