Unable to fetch tha last 30 days data from firebase-CodePudding

I am trying to fetch the last 30 days posts from firebase and I am trying to use the timestamp in the posts in order to do so. But I am not able to fetch the data.

Kotlin Code:

var database:DatabaseReference=Firebase.database.reference
        database.orderByChild("timestamp")
        val postListener = object : ValueEventListener {
            @RequiresApi(Build.VERSION_CODES.O)
            override fun onDataChange(dataSnapshot: DataSnapshot) {
                // Get Post object and use the values to update the UI
                for(postSnapshot in dataSnapshot.children)
                {
                    if(postSnapshot.child("timestamp").value.toString().toInt()>Time.from(Instant.now().minusSeconds(30*24*60*60)).toString().toInt())
                    {
                        val Post = postSnapshot.getValue(PostsModel::class.java)
                        postsList.add(Post!!)
                    }

                }
            }

            override fun onCancelled(databaseError: DatabaseError) {
                // Getting Post failed, log a message
                Timber.d("failed")
            }
        }

Firebase Data Structure:

CodePudding user response：

You need to add a condition that the time must be more than a month ago, then you will produce a list of suitable data. The error can also be at another level that you did not provide (data organization or perhaps you did not connect a listener)

Firebase.database.reference
    .whereGreaterThan("timestamp", Calendar.getInstance().also { it.add(Calendar.MONTH, -1) }.timeInMillis)

CodePudding user response：

You're declaring a listener, but you're not attaching it to the database. Until you call addValueEventListener, addListenerForSingleValueEvent , or get().

I recommend studying the Firebase documentation on reading data as it shows how to do those.