CODEWITHSUNDEEP
androidkotlinandroid-recyclerview
bloxofcode
bloxofcode

Reputation: 23

How to get the variable value from adapter to activities in android kotlin recyclerview?

I'm creating a chat app in android using kotlin and wanted to create a group item based on registered users.

Currently I'm facing a problem on finding a way to pass the variable from the adapter going back to activities because i want to have a floating check button and display what are the selected users from that adapter.

I browse the web but haven't found an ideal write-up about adaptes to activites.

Please point me to some solutions/helpful articles about this. Or if this question is duplicated and answered successfully.

Thanks

AddUserGroupAdapter.kt

....

override fun populateViewHolder(viewHolder: AddUsersGroupAdapter.ViewHolder?, user : Users?, position: Int) {
        var userId = getRef(position).key

        viewHolder!!.bindView(user!!,context)


        viewHolder.itemView.setOnClickListener {
            if(viewHolder.userSelected!!){
                viewHolder.userSelected = false
                //viewHolder!!.bindView(user!!,context)
                viewHolder.userCheck!!.visibility = View.GONE

            }else{
                viewHolder.userSelected = true
                viewHolder.userCheck!!.visibility = View.VISIBLE
            }

            //TODO : I want to collect the Id's into list and 
            // will access to the activity(AddUserGroupActivity)
            //Toast.makeText(context,userId,Toast.LENGTH_LONG).show()

        }


    }

AddUserGroupActivity.kt

...

class AddUsersGroupActivity : AppCompatActivity() {
    var mUserDatabase : DatabaseReference? = null
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_add_users_group)

        supportActionBar!!.setTitle("Add Users in Group")
        supportActionBar!!.setDisplayHomeAsUpEnabled(true)



        var lineaLayoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)

        mUserDatabase = FirebaseDatabase.getInstance().reference
                .child("Users")

        rvAddUsersGroup.setHasFixedSize(true)

        rvAddUsersGroup.layoutManager = lineaLayoutManager
        rvAddUsersGroup.adapter = AddUsersGroupAdapter(mUserDatabase!!, this)

        //TODO : This is where I wanted to have a floating action button onClickListener
        //that will access the variable from adapter and display to toast.
    }
}

Upvotes: 2

Views: 5093

Answers (2)

Artem
Artem

Reputation: 303

you could pass data from adapter to the activity by three ways

  1. add CallBack
  2. (context.applicationContext as? BaseActivity)?.doSomething(variable)
  3. using Broadcast

but if you could get data from outside of Adapter by the number of pressed element, use

... Interface

interface  OnItemClickListener {
   fun onItemClick(index: Int)
}

... Adapter

var mOnItemClickListener: OnItemClickListener? = null

... Holder

 v.setOnClickListener {
            mOnItemClickListener?.onItemClick(adapterPosition)
        }

... Activity

adapter.mOnItemClickListener = object : OnItemClickListener {
        override fun onItemClick(index: Int) {
            mListener?.showDetails(index)
        }

    }

Upvotes: 4

RediOne1
RediOne1

Reputation: 10699

Add listerner to you ViewHolder which will notify your adapter and in adapter forward this notification to activity.

override fun populateViewHolder(viewHolder: AddUsersGroupAdapter.ViewHolder?, user : Users?, position: Int, userSelectionListener: (Users, Boolean) -> Unit) {
    var userId = getRef(position).key

    viewHolder!!.bindView(user!!,context)


    viewHolder.itemView.setOnClickListener {
        if(viewHolder.userSelected!!){
            viewHolder.userSelected = false
            //viewHolder!!.bindView(user!!,context)
            viewHolder.userCheck!!.visibility = View.GONE
           usersSelectionListener.invoke(user, true)

        }else{
            viewHolder.userSelected = true
            viewHolder.userCheck!!.visibility = View.VISIBLE
           usersSelectionListener.invoke(user, false)
        }

        //TODO : I want to collect the Id's into list and 
        // will access to the activity(AddUserGroupActivity)
        //Toast.makeText(context,userId,Toast.LENGTH_LONG).show()

    }
}

Add same parameter to your Adapter constructor, then in activity handle this listener:

rvAddUsersGroup.adapter = AddUsersGroupAdapter(mUserDatabase!!, this) { user: User, isSelected: Boolean -> 
    //Do want you want with user and selection.
}

Upvotes: 1

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