Kotlin Android开发：声明GroupieViewHolder时出错求助

我是Kotlin Android开发新手，正在跟着教程开发即时通讯应用，但GroupieViewHolder一直无法正常工作，已经花了4小时排查仍未解决。以下是我的项目配置、代码及错误截图：

项目级gradle文件 #

buildscript {
    ext.kotlin_version = '1.6.21'

    repositories {
        mavenCentral()
    }

    dependencies {
        classpath 'com.google.gms:google-services:4.3.14'

        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

plugins {
    id 'com.android.application' version '7.2.1' apply false
    id 'com.android.library' version '7.2.1' apply false
    id 'org.jetbrains.kotlin.android' version '1.7.10' apply false

}


task clean(type: Delete) {
    delete rootProject.buildDir
}

应用级gradle文件 #

plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
    id 'com.google.gms.google-services'
    id 'kotlin-android-extensions'
}

apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'

android {
    compileSdk 32

    androidExtensions {
        experimental = true
    }

    defaultConfig {
        applicationId "com.example.assignment"
        minSdk 21
        targetSdk 32
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }

    buildFeatures {
        viewBinding true
    }


    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }


}

dependencies {

    implementation 'androidx.core:core-ktx:1.7.0'
    implementation 'androidx.appcompat:appcompat:1.5.1'
    implementation 'com.google.android.material:material:1.6.1'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
    implementation 'com.google.firebase:firebase-auth-ktx:21.1.0'

    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'

    implementation platform('com.google.firebase:firebase-bom:31.0.1')
    implementation 'com.google.firebase:firebase-analytics-ktx'
    implementation 'com.google.firebase:firebase-storage-ktx'
    implementation 'com.google.firebase:firebase-database-ktx'

    implementation 'de.hdodenhof:circleimageview:3.1.0'

    // 进度对话框库
    implementation 'com.jpardogo.googleprogressbar:library:1.2.0'

    // 无法将groupie添加到gradle
    //implementation "com.github.lisawray.groupie:groupie:$groupie_version"
    implementation "com.github.lisawray.groupie:groupie:2.10.0"
    implementation 'com.github.lisawray.groupie:groupie-kotlin-android-extensions:2.10.0'

    implementation 'com.squareup.picasso:picasso:2.71828'
}

settings.gradle文件 #

pluginManagement {
    repositories {
        gradlePluginPortal()
        google()
        mavenCentral()
    }
}
dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        google()
        mavenCentral()
        maven { url 'https://jitpack.io' }  
       jcenter() 
    }
}
rootProject.name = "Assignment"
include ':app'

NewMessageActivity.kt代码 #

package com.example.assignment

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import com.google.firebase.database.DataSnapshot
import com.google.firebase.database.DatabaseError
import com.google.firebase.database.FirebaseDatabase
import com.google.firebase.database.ValueEventListener
import com.squareup.picasso.Picasso
import com.xwray.groupie.GroupieAdapter
import kotlinx.android.synthetic.main.activity_new_message.*

import com.xwray.groupie.kotlinandroidextensions.Item
import com.xwray.groupie.kotlinandroidextensions.GroupieViewHolder
import kotlinx.android.synthetic.main.song.*  // 无法导入该布局
import kotlinx.android.synthetic.main.my_item_layout.* // 无法导入该布局
import kotlinx.android.synthetic.main.user_row_new_message.view.*

class NewMessageActivity : AppCompatActivity() {


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_new_message)

        supportActionBar?.title="选择用户"

        fetchUsers()
    }

    private fun fetchUsers() {
        val ref = FirebaseDatabase.getInstance().getReference("/Users")
        ref.addListenerForSingleValueEvent(object: ValueEventListener {
            override fun onDataChange(p0: DataSnapshot) {
                val adapter = GroupieAdapter<GroupieViewHolder>() // 此处报错

                p0.children.forEach {
                    Log.d("NewMessage", it.toString())
                    val user = it.getValue(User::class.java)
                    if(user != null) {
                        adapter.add(UserItem(user))
                    }

                }
                recyclerview_newmessage.adapter=adapter
            }

            override fun onCancelled(p0: DatabaseError) {
                TODO("尚未实现")
            }
        }) // 原代码缺失闭合括号，已补充
    }
}
class UserItem(val user: User): Item<GroupieViewHolder>() { // 此处报错
    override fun bind(viewHolder: GroupieViewHolder, position: Int) {
        viewHolder.itemView.username_textview_new_message.text = user.username
        Picasso.get().load(user.profileImageUrl).into(viewHolder.itemView.imageview_new_message)
    }

    override fun getLayout(): Int {
        return R.layout.user_row_new_message
    }
}

错误截图 #

解决方案 #

1. 修复Gradle版本冲突 #

项目级gradle中kotlin版本为1.6.21，但应用级插件使用1.7.10，版本不一致会导致编译异常。统一版本：

• 修改项目级gradle的ext.kotlin_version = '1.7.10'，保证kotlin-gradle-plugin与kotlin-android插件版本匹配

2. 移除过时的Kotlin Android Extensions #

kotlin-android-extensions已被官方弃用，且Groupie的groupie-kotlin-android-extensions模块停止维护，改用View Binding替代：

• 从应用级gradle的plugins中移除id 'kotlin-android-extensions'，删除apply plugin: 'kotlin-android-extensions'和androidExtensions配置块
• 移除groupie-kotlin-android-extensions依赖，仅保留核心Groupie依赖：

  implementation "com.github.lisawray.groupie:groupie:2.10.0"
  

3. 修正代码语法与导入问题 #

• 删除无法导入的无用布局导入：kotlinx.android.synthetic.main.song.*和kotlinx.android.synthetic.main.my_item_layout.*
• GroupieAdapter无需指定泛型，直接初始化：val adapter = GroupieAdapter()
• 修改UserItem继承逻辑，使用标准Groupie ViewHolder：

  import com.xwray.groupie.Item
  import com.xwray.groupie.ViewHolder
  
  class UserItem(val user: User): Item<ViewHolder>() {
      override fun bind(viewHolder: ViewHolder, position: Int) {
          viewHolder.itemView.username_textview_new_message.text = user.username
          Picasso.get().load(user.profileImageUrl).into(viewHolder.itemView.imageview_new_message)
      }
  
      override fun getLayout(): Int {
          return R.layout.user_row_new_message
      }
  }
  

4. 同步并重建项目 #

• 点击Android Studio的File -> Sync Project with Gradle Files同步配置
• 执行Build -> Clean Project和Build -> Rebuild Project清理重建项目

内容的提问来源于stack exchange，提问作者mkk