在 RecyclerView Adapter Android Kotlin 中实现绑定

Question

所以你好，我这里有个小问题。

我无法正确实现对 RecycleView 适配器的绑定。我需要它来在购物车中显示我的产品，如下面的代码所示。我是适配器的初学者，所以请帮助我。

CartItemsListAdapter.kt *这里是我要实现绑定的地方*

class CartItemsListAdapter(
private val context: Context,
private var list: ArrayList<CartItem>
) : RecyclerView.Adapter<RecyclerView.ViewHolder>(){


override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): 
RecyclerView.ViewHolder {
    return MyViewHolder(
        LayoutInflater.from(context).inflate(
            R.layout.item_cart_layout,
            parent,
            false
        )
    )
}

override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
    val model = list[position]
    if (holder is MyViewHolder) {
        Glide.with(context)
            .load(model.image)
            .placeholder(R.drawable.ic_launcher)
            .into(/*binding.ivCartItemImage*/)
        //binding.tvCartItemPrice.text = model.price
        //binding.tvCartItemTitle.text = model.title
    }
}

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

private class MyViewHolder(view: View) : RecyclerView.ViewHolder(view)
}

activity_cart_list.xml *xml 文件以供参考以及我想从哪里获取这些绑定*

<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"
tools:context=".ui.activities.CartListActivity">

<androidx.appcompat.widget.Toolbar
    android:id="@+id/toolbar_cart_list_activity"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    android:background="?attr/colorSecondary">

    <ImageView
        android:id="@+id/arrow_back"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/ic_arrow_left"
        android:hapticFeedbackEnabled="true"
        android:layout_marginTop="16sp"
        android:padding="24dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_gravity="top"
        android:contentDescription="@string/back_button" />

    <com.example.trieskask.utils.OswaldBold
        android:id="@+id/tv_title"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:text="My cart"
        android:textSize="26sp"
        android:elevation="3dp"
        android:textStyle="bold" />

</androidx.appcompat.widget.Toolbar>

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/rv_cart_items_list"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:layout_marginTop="10dp"
    android:visibility="gone"
    app:layout_constraintBottom_toTopOf="@id/ll_checkout"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@id/toolbar_cart_list_activity" />

<com.example.trieskask.utils.OswaldRegular
    android:id="@+id/tv_no_cart_item_found"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:layout_marginEnd="8dp"
    android:text="No cart item found!"
    android:textAlignment="center"
    app:layout_constraintBottom_toTopOf="@id/ll_checkout"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@id/toolbar_cart_list_activity" />

<LinearLayout
    android:id="@+id/ll_checkout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="?attr/colorSecondary"
    android:elevation="4dp"
    android:orientation="vertical"
    android:padding="16dp"
    android:visibility="gone"
    tools:visibility="visible"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <com.example.trieskask.utils.OswaldLight
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Subtotal:" />

        <com.example.trieskask.utils.OswaldLight
            android:id="@+id/tv_sub_total"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAlignment="center"
            tools:text="0" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <com.example.trieskask.utils.OswaldLight
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Shipping charge:" />

        <com.example.trieskask.utils.OswaldLight
            android:id="@+id/tv_shipping_charge"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAlignment="center"
            tools:text="" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <com.example.trieskask.utils.OswaldBold
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="Total Amount" />

        <com.example.trieskask.utils.OswaldBold
            android:id="@+id/tv_total_amount"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAlignment="center"
            tools:text="0" />
    </LinearLayout>

    <com.example.trieskask.utils.OswaldButton
        android:id="@+id/btn_checkout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginStart="16dp"
        android:layout_marginTop="30dp"
        android:layout_marginEnd="16dp"
        android:background="@drawable/btn_ripple_effect"
        android:foreground="?attr/selectableItemBackground"
        android:gravity="center"
        android:text="Checkoutt"
        android:textColor="@android:color/white"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

</LinearLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

感谢您的帮助

Answer 1

您可以重构 MyViewHolder class 以要求 ActivityCartListBinding 作为构造函数参数。那么您的 onCreateViewHolder 函数将如下所示：

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val binding = ActivityCartListBinding.inflate(LayoutInflater.from(parent.context), parent, false)
 
    return MyViewHolder(binding)
}

最后是你的 onBindViewHolder:

override fun onBindViewHolder(
    holder: RecyclerView.ViewHolder, 
    position: Int
) {
    val model = list[position]
    if (holder is MyViewHolder) {
        Glide.with(context)
            .load(model.image)
            .placeholder(R.drawable.ic_launcher)
            .into(/*binding.ivCartItemImage*/)
        holder.getBinding().tvCartItemPrice.text = model.price
        holder.getBinding().tvCartItemTitle.text = model.title
    }
}

视图持有者

private class MyViewHolder(val binding: ActivityCartListBinding) : RecyclerView.ViewHolder(binding.root)

这应该可以解决您的问题。

在 RecyclerView Adapter Android Kotlin 中实现绑定

Implement binding into RecycleView Adapter Android Kotlin

android

kotlin

android-recyclerview