I'm in the process of fiddling my way to a working app using Kotlin and I have hit a roadblock when trying to implement OnClickListeners for my three buttons. I have my RecyclerView populate properly, but despite following the recommendations on this SO post (except in Kotlin) and following the documentation, though I am still having trouble getting the implementation to work.
The code below is my adapter class for the implementation.
class BrowseHabitsAdapter(private val habits: ArrayList<Habit>) :
RecyclerView.Adapter<BrowseHabitsAdapter.ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val itemView = LayoutInflater.from(parent.context).inflate(R.layout.habit_card, parent, false)
return ViewHolder(itemView, object: HabitClickListener {
override fun onDecrease(position: Int) {
val streak = itemView.dayCounter.text.toString().toInt()
itemView.dayCounter.text = streak.dec().toString()
}
override fun onIncrease(position: Int) {
val streak = itemView.dayCounter.text.toString().toInt()
itemView.dayCounter.text = streak.inc().toString()
}
override fun onEdit(position: Int) {
TODO("Change Activity to Edit")
}
})
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val currentItem = habits[position]
holder.habitTitle.text = currentItem.title
holder.streak.text = currentItem.streak.toString()
}
override fun getItemCount() = habits.size
class ViewHolder(itemView : View, listener : HabitClickListener) : RecyclerView.ViewHolder(itemView), View.OnClickListener {
val habitTitle: TextView = itemView.habitTitle
val streak: TextView = itemView.dayCounter
val decreaseCounterButton : Button = itemView.decreaseCounterButton
val increaseCounterButton : Button = itemView.increaseCounterButton
val listener = listener
init {
decreaseCounterButton.setOnClickListener(this)
increaseCounterButton.setOnClickListener(this)
}
override fun onClick(v: View?) {
when (itemView.id) {
itemView.decreaseCounterButton.id -> listener.onDecrease(this.layoutPosition)
itemView.increaseCounterButton.id -> listener.onIncrease(this.layoutPosition)
}
}
}
interface HabitClickListener {
fun onDecrease(position : Int)
fun onIncrease(position : Int)
fun onEdit(position : Int)
}
}
and the following is my XML code defining one of my cards:
<?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:id="@+id/cardView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_marginTop="10dp"
android:layout_marginEnd="10dp"
app:cardBackgroundColor="#eeeeee"
app:cardCornerRadius="10dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:context=".MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:id="@+id/cardHeader"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<TextView
android:id="@+id/habitTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:layout_marginRight="10dp"
android:text="@string/default_card_title"
android:textSize="18sp" />
<Space
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_weight="1" />
<ImageView
android:id="@+id/settingsIcon"
android:layout_width="25dp"
android:layout_height="25dp"
android:layout_gravity="bottom"
android:layout_marginRight="10dp"
app:srcCompat="@android:drawable/ic_menu_manage" />
</LinearLayout>
<LinearLayout
android:id="@+id/cardControls"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="horizontal">
<Button
android:id="@+id/decreaseCounterButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="-"
android:textAllCaps="false"
android:textSize="30sp" />
<Space
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1" />
<TextView
android:id="@+id/dayCounter"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:fontFamily="sans-serif-medium"
android:text="0"
android:textAlignment="center"
android:textSize="30sp"
android:textStyle="bold" />
<Space
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1" />
<Button
android:id="@+id/increaseCounterButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="+"
android:textSize="30sp" />
</LinearLayout>
</LinearLayout>
</androidx.cardview.widget.CardView>
Any additional explanation that can be provided as to what I did wrong and what is going on in detail would be really appreciated!
