CODEWITHSUNDEEP
androidfirebasefirebase-realtime-database
Junburg
Junburg

Reputation: 360

Android, Firebase How to get only boolean data from database and count them

I just wanna get boolean data from my firebase database and then count how many boolean data in.

This is my json tree in my database.

       "user_study_condition" : {
"1lYNWnabn7a6mj9cPOcayHOGUjx2" : {
  "algorithm" : {
    "bubble" : true,
    "insert" : false,
    "name" : "알고리즘"
  },
  "data_structure" : {
    "name" : "자료구조",
    "queue" : true,
    "stack" : false
  }
}

}

I want to count only true data. In this tree, I will count 2 true data. and then add to the List. I already know how to retrieve data from database like 'addSingleValueListener... addValueListener..'

But I don't know how to count boolean data amount.

I have to count boolean data dynamically. because subject will be created dynamically. and boolean data will be changed frequently. So I would like to know the solution considering this.

Thank you for your reply.

Upvotes: 1

Views: 1470

Answers (2)

Android_K.Doe
Android_K.Doe

Reputation: 753

You can do this by using equalTo

myRef.orderByChild(childName).equalTo(true);

then on your listener you can get the count by

dataSnapShot.getChildrenCount()

Hope this helps

EDIT:

Try this one for dynamic keys. First is getting your base refrence. Example

myRef = ref.child("1lYNWnabn7a6mj9cPOcayHOGUjx2")

Then add listener to this then inside the listener do this

for (DataSnapshot snapShot: dataSnapshot.getChildren()) {
   Map<String, Object> mp= (Map<String, Object>) snapShot.getValue();

   //First is to check if it contains true
   if(mp.containsValue(true)){
     Iterator it = mp.entrySet().iterator();
     while (it.hasNext()) {
        Map.Entry pair = (Map.Entry)it.next();

        //If object is a boolean check if it is true
        if(pair.getValue() instanceof Boolean){
           if(pair.getValue()){
              //This mean that we have 1 true
              ctrTrue++;

              //This refers to the child reference
              //For example "1lYNWnabn7a6mj9cPOcayHOGUjx2/algorithm"
              DatabaseReference itemRef = myRef.child(pair.getKey())
           }
        }
        it.remove();
     }
   }
}

Upvotes: 3

92AlanC
92AlanC

Reputation: 1387

If you're sure the only boolean fields in your object are bubble, insert, queue and stack you can create a boolean list and add the value of these fields to it. Then you can do the following:

Java

List<Boolean> booleanFields = new ArrayList<>();
booleanFields.add(algorithm.isBubble());
booleanFields.add(algorithm.isInsert());
booleanFields.add(dataStructure.isQueue());
booleanFields.add(dataStructure.isStack());    

int trueCount = 0;
for (boolean field : booleanFields)
    if (item) trueCount++;

Kotlin

val booleanFields = ArrayList<Boolean>()
booleanFields.add(algorithm.isBubble)
booleanFields.add(algorithm.isInsert)
booleanFields.add(dataStructure.isQueue)
booleanFields.add(dataStructure.isStack)

val count = booleanFields.count { it }

Upvotes: 2

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