RECYCLE VIEW onBindFucntion not working as I am following and learnign through a tuitorial-CodePudding

So i have been following this tuitorial and for soem reason I can not import my text from xml to kotlin file. I have tried diffrent things but it still wont work.

I did add id 'kotlin-android-extensions' to my gradle:module:app but still wot go though.

Here is my code

todoAdapter.kt `

package com.example.todo

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.appcompat.view.menu.ActionMenuItemView
import androidx.recyclerview.widget.RecyclerView

class todoAdapter(
    private val todos : MutableList<Todo>
):RecyclerView.Adapter<todoAdapter.TodoViewHolder>() {

    class TodoViewHolder(itemView:View): RecyclerView.ViewHolder(itemView)

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

    override fun onBindViewHolder(holder: TodoViewHolder, position: Int) {
           val curTodo =  todos[position]

           holder.itemView.tv (this bracket is not included in the code, the reason i onyl wrote tv is that if i wrote full it would be a red text and not get thr refrence)


    }

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

item_todo.xml

<?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"
    android:layout_width="match_parent"
    android:layout_height="70dp"
    android:paddingStart="14dp"
    android:paddingEnd="14dp">

    <TextView
        android:id="@ id/tvTodoTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Example"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <CheckBox
        android:id="@ id/tvCheckboxTodo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

I have tried using the apply but that funciton too doesnt seem to work , I just wanna know where I am doing htinsg wrong. Please expalin begnier level as I am still lenring

CodePudding user response：

I think you meant to do this:

class TodoViewHolder(itemView:View): RecyclerView.ViewHolder(itemView) {
    val tvTodoTitle: TextView = itemView.findViewById(R.id.tvTodoTitle)
    val tvCheckboxTodo: Checkbox = itemView.findViewById(R.id.tvCheckboxTodo)
}

Then in your onBindViewHolder you can do

holder.tvTodoTitle.text = "Whatever you want"

CodePudding user response：

You must create the reference first then you can call it later. You can create tvTodoTitle in the body of class TodoViewHolder by the following code:

TextView tvTodoTitle = itemView.findViewById(R.id.tvTodoTitle);

then in onBindViewHolder you can call the tvTodoTitle reference:

holder.itemView.tvTodoTitle ...