Thiết kế website giá rẻ

Question

I have a an Activity called ShoppingListActivity. The only thing it has in its layout is a fragment called ShoppingListFragment. That fragment get a listId as a parameter and should list all items within the list with id = listId in a RecyclerView and the name of that list. When the ShoppingListFragment gets called the name is displayed correctly but the recyclerview is never displayed.

The code for the ShoppingListActivity is:

class ShoppingListActivity : AppCompatActivity() {


    private var _binding: ActivityShoppingListBinding? = null
    private val binding get() = _binding!!

    private lateinit var shoppingListViewModel: ShoppingListViewModel
    private lateinit var shoppingListNameTextView: TextView
    private lateinit var recyclerView: RecyclerView
    private lateinit var shoppingList: ShoppingList

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_shopping_list)

        var listId = intent.getIntExtra("ShoppingListId",0)

        if(savedInstanceState == null)
        {
            supportFragmentManager.commit {
                add(R.id.shopping_list_fragment, ShoppingListFragment(listId))
                setReorderingAllowed(true)
            }
        }
    }
}

The .xml file for the ShoppingListActivity:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/activity_shopping_list"
    tools:context=".Activities.ShoppingListActivity">

    <androidx.fragment.app.FragmentContainerView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/shopping_list_fragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Code for ShoppingListFragment:


class ShoppingListFragment(private val listId:Int) : Fragment() {


    private var _binding: FragmentShoppingListBinding? = null
    private val binding get() = _binding!!

    private lateinit var shoppingListViewModel: ShoppingListViewModel
    private lateinit var shoppingListNameTextView: TextView
    private lateinit var recyclerView: RecyclerView
    private lateinit var shoppingList: ShoppingList


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_shopping_list, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        //DVATA VIEWMODELS, DA SE ZEMI LISTATA SO ITEMS I DA SE PUSTI NAPRED
        _binding = FragmentShoppingListBinding.bind(view)
        recyclerView = binding.shoppingListRecyclerView

        var context = requireContext()
        val shoppingListViewModelFactory = ShoppingListViewModelFactory(context)
        shoppingListViewModel = ViewModelProvider(this,shoppingListViewModelFactory)[ShoppingListViewModel::class.java]

        shoppingListNameTextView = binding.shoppingListName
        shoppingList = shoppingListViewModel.getListById(listId)

        shoppingListNameTextView.text = shoppingList.Name

        var itemsInList = shoppingListViewModel.getItemsInShoppingList(shoppingList)

        var adapter = SingleShoppingListAdapter(itemsInList)

        recyclerView.adapter = adapter
    }

}

The code for the .xml file for the ShoppingListFragment:


<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/shopping_list_fragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".UI.Fragments.ShoppingListFragment">

    <TextView
        android:id="@+id/shopping_list_name"
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="52dp"

        android:layout_marginTop="44dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.recyclerview.widget.RecyclerView
        android:layout_width="50dp"
        android:id="@+id/shopping_list_recycler_view"
        android:layout_height="150dp"
        android:layout_marginTop="60dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/shopping_list_name"
        app:layout_constraintVertical_bias="0.0" />

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/add_item_to_shopping_list"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="60dp"
        android:layout_marginBottom="76dp"
        android:clickable="true"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:srcCompat="@android:drawable/ic_menu_add" />


</androidx.constraintlayout.widget.ConstraintLayout>

The code for recycler_view_shopping_list_item_element.xml:


<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="10dp"
        android:layout_height="match_parent">

        <TextView
            android:id="@+id/shopping_list_item_name"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            tools:layout_editor_absoluteX="-16dp"
            app:layout_constraintTop_toTopOf="parent"
            tools:layout_editor_absoluteY="1dp" />

        <TextView
            android:id="@+id/shopping_list_item_quantity"
            android:layout_width="10dp"
            android:layout_height="wrap_content"
            app:layout_constraintTop_toBottomOf="@+id/shopping_list_item_name"
            tools:layout_editor_absoluteX="0dp" />



    </androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>

The code for the SingleShoppingListAdapter:


class SingleShoppingListAdapter(private val listItems: ArrayList<ShoppingListItem>) : RecyclerView.Adapter<SingleShoppingListAdapter.SingleShoppingListViewHolder>() {
    inner class SingleShoppingListViewHolder(view: View) : RecyclerView.ViewHolder(view) {

        private var name: TextView = view.findViewById(R.id.shopping_list_item_name)
        private var quantity: TextView = view.findViewById(R.id.shopping_list_item_quantity)
        fun bind(item: ShoppingListItem)
        {
            name.text = item.Name
            quantity.text = item.Quantity.toString()
        }
    }

    override fun onCreateViewHolder(
        parent: ViewGroup,
        viewType: Int
    ): SingleShoppingListViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.recycler_view_shopping_list_item_element,parent,false)
    return SingleShoppingListViewHolder(view)
}

override fun getItemCount(): Int {
        return listItems.size
    }

    override fun onBindViewHolder(holder: SingleShoppingListViewHolder, position: Int) {
        holder.bind(listItems[position])
    }
}

When i tried debugging it the listItems passed to the adapter is never empty and the adapter gets created but the onCreateViewHolder, getItemCount, onBindViewHolder methods are never called.

Thiết kế website giá rẻ

Danh mục

Adapter not called when working with RecyclerView in Kotlin