Display all registered users Posts and Following-CodePudding

Here is the code I've tried. It only displays posts of the current user Here is the image of the firebase database to describe what I am trying to do:

I don't mind if the answer comes in java code too. I appreciate your assistance.

private fun retrievePosts() {

    progressBar!!.visibility = View.VISIBLE

    val postsRef = FirebaseDatabase.getInstance().reference.child("Catalog").child(uid!!)

    postsRef.addValueEventListener(object : ValueEventListener {
        override fun onDataChange(p0: DataSnapshot) {
            (postList as ArrayList<ModelPost>).clear()

            for (snapshot in p0.children) {
                val post = snapshot.getValue(ModelPost::class.java)

                for (id in (followingList as ArrayList<String>)) {
                    if (post!!.getUid() == id) {
                        (postList as ArrayList<ModelPost>).add(post!!)

                        progressBar!!.visibility = View.GONE
                    }

                    adapterPost!!.notifyDataSetChanged()
                }
            }

        }

        override fun onCancelled(p0: DatabaseError) {
            progressBar!!.visibility = View.GONE
        }
    })
}

CodePudding user response：

You're only reading the posts of the current user from the database with this: val postsRef = FirebaseDatabase.getInstance().reference.child("Catalog").child(uid!!).

To read the posts from all users, you should initialize val postsRef = FirebaseDatabase.getInstance().reference.child("Catalog"), and then add an extra loop (across the user nodes) in your onDataChange.

So something like:

val postsRef = FirebaseDatabase.getInstance().reference.child("Catalog")

postsRef.addValueEventListener(object : ValueEventListener {
    override fun onDataChange(p0: DataSnapshot) {
    (postList as ArrayList<ModelPost>).clear()

    for (userSnapshot in p0.children) {
        for (snapshot in userSnapshot.children) {
            val post = snapshot.getValue(ModelPost::class.java)
            ...