Why dynamic lists display data efficiently in Android Kotlin - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a RecyclerView adapter class in Kotlin.

Android Kotlin

class MyAdapter(private val items: List<String>) : RecyclerView.[1]<MyAdapter.ViewHolder>() {
  // Adapter implementation
}

Drag options to blanks, or click blank then click option'

ARecyclerView.Adapter

BRecyclerView.ViewHolder

CViewHolder

DAdapter

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'RecyclerView.Adapter' duplicates the RecyclerView prefix, causing compilation errors.

Confusing ViewHolder with Adapter class.

The adapter class must extend RecyclerView.Adapter to work with RecyclerView.

2fill in blank

medium

Complete the code to inflate the item layout in onCreateViewHolder method.

Android Kotlin

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
  val view = LayoutInflater.from(parent.context).inflate([1], parent, false)
  return ViewHolder(view)
}

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AR.id.item_view

BR.layout.item_view

CR.string.item_view

DR.drawable.item_view

Attempts:

3 left

💡 Hint

Common Mistakes

Using R.id or R.string instead of R.layout causes runtime errors.

Passing null instead of parent causes layout issues.

LayoutInflater.inflate requires a layout resource ID, which is R.layout.item_view.

3fill in blank

hard

Fix the error in binding data to the TextView inside onBindViewHolder.

Android Kotlin

override fun onBindViewHolder(holder: ViewHolder, position: Int) {
  holder.textView.[1] = items[position]
}

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Atext

BgetText()

CsetText()

DtextView

Attempts:

3 left

💡 Hint

Common Mistakes

Using setText() like in Java causes syntax errors in Kotlin.

Using getText() tries to read text instead of setting it.

In Kotlin Android extensions, you set the text of a TextView by assigning to its text property.

4fill in blank

hard

Fill both blanks to create a list that updates efficiently with RecyclerView.

Android Kotlin

val recyclerView = findViewById<RecyclerView>(R.id.recyclerView)
recyclerView.layoutManager = [1](this)
recyclerView.adapter = MyAdapter([2])

Drag options to blanks, or click blank then click option'

ALinearLayoutManager

BGridLayoutManager

ClistOf("Apple", "Banana", "Cherry")

DarrayListOf("Apple", "Banana", "Cherry")

Attempts:

3 left

💡 Hint

Common Mistakes

Using GridLayoutManager without understanding layout changes.

Using immutable listOf when data needs to change.

RecyclerView needs a LayoutManager like LinearLayoutManager to arrange items vertically. The adapter needs a list, and arrayListOf is a mutable list suitable for dynamic updates.

5fill in blank

hard

Fill all three blanks to implement ViewHolder class with a TextView reference.

Android Kotlin

class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
  val [1]: TextView = itemView.findViewById([2])
  fun bind(text: String) {
    [3].text = text
  }
}

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AtextView

BR.id.textView

CitemView

Dtext

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names causes errors.

Using itemView instead of R.id.textView in findViewById.

The ViewHolder holds a reference to the TextView named textView. It finds it by R.id.textView. The bind function sets the text on this textView.