Android实现RecyclerView边缘渐变效果

1.前言：

是指在RecyclerView中实现淡入淡出效果的边缘效果。通过这种效果，可以使RecyclerView的边缘在滚动时逐渐淡出或淡入，以提升用户体验。

2.Recyclerview属性：

2.1、requiresFadingEdge：属性用来设置拉滚动条时，边框渐变的方向。

none（边框颜色不变）
horizontal（水平方向颜色变淡）
vertical（垂直方向颜色变淡）

2.2、fadingEdgeLength：用来设置边框渐变的长度

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv_effect"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:fadingEdgeLength="40dp"
        android:fadingEdge="vertical"
        android:requiresFadingEdge="vertical"
        tools:listitem="@layout/item_effect"
        android:padding="15dp"/>

3.简单适配器：

package com.cloud.recyclervieweffectdemo.adapter

import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import com.cloud.recyclervieweffectdemo.R
import com.cloud.recyclervieweffectdemo.bean.EffectBean

/**
 * @author: njb
 * @date:   2024/12/10 23:14
 * @desc:   描述
 */
class EffectAdapter(private val dataList: MutableList<EffectBean>) : RecyclerView.Adapter<EffectAdapter.EffectViewHolder>() {

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

    }

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

    override fun onBindViewHolder(holder: EffectViewHolder, position: Int) {
        val data = dataList[position]
        holder.textView.text = data.name
    }

    class EffectViewHolder(itemView: View) :RecyclerView.ViewHolder(itemView){
        val textView:TextView = itemView.findViewById(R.id.tv_name)
        val ivAvatar:ImageView = itemView.findViewById(R.id.iv_avatar)
    }
}

4.实体类：

package com.cloud.recyclervieweffectdemo.bean

/**
 * @author: njb
 * @date:   2024/12/10 23:16
 * @desc:   描述
 */
data class EffectBean(
    var name:String = "",
    var avatar:String = ""
)

5.主界面布局：

<?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/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv_effect"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:fadingEdgeLength="40dp"
        android:fadingEdge="vertical"
        android:requiresFadingEdge="vertical"
        tools:listitem="@layout/item_effect"
        android:padding="15dp"/>

</androidx.constraintlayout.widget.ConstraintLayout>

6.item布局：

<?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="wrap_content">

    <ImageView
        android:id="@+id/iv_avatar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:scaleType="fitCenter"
        android:src="@mipmap/ic_girl"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.appcompat.widget.AppCompatTextView
        android:id="@+id/tv_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="天地"
        android:textColor="@color/black"
        android:textSize="24sp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/iv_avatar" />
</androidx.constraintlayout.widget.ConstraintLayout>

7.测试代码：

竖向渐变

package com.cloud.recyclervieweffectdemo

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.cloud.recyclervieweffectdemo.adapter.EffectAdapter
import com.cloud.recyclervieweffectdemo.bean.EffectBean

class MainActivity : AppCompatActivity() {
    private var adapter:EffectAdapter ?= null
    private var dataList:MutableList<EffectBean> ?= null
    private val rvEffect:RecyclerView by lazy { findViewById(R.id.rv_effect) }
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
       initData()
       initAdapter()
    }

    private fun initData() {
        val effectBean = EffectBean()
        dataList = ArrayList()
        for(i in 1..15){
            effectBean.name = "小麦"
            effectBean.avatar = "222"
            dataList?.add(effectBean)
        }
    }

    private fun initAdapter() {
        adapter = dataList?.let { EffectAdapter(it) }
        rvEffect.layoutManager = LinearLayoutManager(this)
        rvEffect.adapter = adapter
    }
}

8.横向渐变：

package com.cloud.recyclervieweffectdemo

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.cloud.recyclervieweffectdemo.adapter.EffectAdapter
import com.cloud.recyclervieweffectdemo.bean.EffectBean

class MainActivity : AppCompatActivity() {
    private var adapter:EffectAdapter ?= null
    private var dataList:MutableList<EffectBean> ?= null
    private val rvEffect:RecyclerView by lazy { findViewById(R.id.rv_effect) }
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
       initData()
       initAdapter()
    }

    private fun initData() {
        val effectBean = EffectBean()
        dataList = ArrayList()
        for(i in 1..15){
            effectBean.name = "小麦"
            effectBean.avatar = "222"
            dataList?.add(effectBean)
        }
    }

    private fun initAdapter() {
        adapter = dataList?.let { EffectAdapter(it) }
        rvEffect.layoutManager = LinearLayoutManager(this,LinearLayoutManager.HORIZONTAL,false)
        rvEffect.adapter = adapter
    }
}

<?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/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/rv_effect"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:fadingEdgeLength="40dp"
        android:fadingEdge="horizontal"
        android:requiresFadingEdge="horizontal"
        tools:listitem="@layout/item_effect"
        android:padding="15dp"/>

</androidx.constraintlayout.widget.ConstraintLayout>