使用 Kotlin 在 Android 应用中使用 RecyclerView?
此示例演示了如何在 Android 应用中使用 Kotlin 使用 RecyclerView。
步骤 1 − 在 Android Studio 中创建一个新项目,转到文件?新建项目,并填写所有必需的详细信息以创建新项目。
步骤 2 − 将以下代码添加到 res/layout/activity_main.xml。
示例
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/rlMain" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_margin="16dp" android:orientation="vertical"> <androidx.recyclerview.widget.RecyclerView android:id="@+id/recyclerView" android:layout_width="match_parent" android:layout_height="match_parent" /> </LinearLayout>
步骤 3 − 将以下代码添加到 src/MainActivity.kt
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.DefaultItemAnimator
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
class MainActivity : AppCompatActivity() {
private val movieList = ArrayList<MovieModel>()
private lateinit var moviesAdapter: MoviesAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
title = "KotlinApp"
val recyclerView: RecyclerView = findViewById(R.id.recyclerView)
moviesAdapter = MoviesAdapter(movieList)
val layoutManager = LinearLayoutManager(applicationContext)
recyclerView.layoutManager = layoutManager
recyclerView.itemAnimator = DefaultItemAnimator()
recyclerView.adapter = moviesAdapter
prepareMovieData()
}
private fun prepareMovieData() {
var movie = MovieModel("Mad Max: Fury Road", "Action & Adventure", "2015")
movieList.add(movie)
movie = MovieModel("Inside Out", "Animation, Kids & Family", "2015")
movieList.add(movie)
movie = MovieModel("Star Wars: Episode VII - The Force Awakens", "Action", "2015")
movieList.add(movie)
movie = MovieModel("Shaun the Sheep", "Animation", "2015")
movieList.add(movie)
movie = MovieModel("The Martian", "Science Fiction & Fantasy", "2015")
movieList.add(movie)
movie = MovieModel("Mission: Impossible Rogue Nation", "Action", "2015")
movieList.add(movie)
movie = MovieModel("Up", "Animation", "2009")
movieList.add(movie)
movie = MovieModel("Star Trek", "Science Fiction", "2009")
movieList.add(movie)
movie = MovieModel("The LEGO MovieModel", "Animation", "2014")
movieList.add(movie)
movie = MovieModel("Iron Man", "Action & Adventure", "2008")
movieList.add(movie)
movie = MovieModel("Aliens", "Science Fiction", "1986")
movieList.add(movie)
movie = MovieModel("Chicken Run", "Animation", "2000")
movieList.add(movie)
movie = MovieModel("Back to the Future", "Science Fiction", "1985")
movieList.add(movie)
movie = MovieModel("Raiders of the Lost Ark", "Action & Adventure", "1981")
movieList.add(movie)
movie = MovieModel("Goldfinger", "Action & Adventure", "1965")
movieList.add(movie)
movie = MovieModel("Guardians of the Galaxy", "Science Fiction & Fantasy", "2014")
movieList.add(movie)
moviesAdapter.notifyDataSetChanged()
}
}步骤 4 − 创建一个新的类 MovieModel.kt 并添加以下代码 −
class MovieModel(title: String?, genre: String?, year: String?) {
private var title: String
private var genre: String
private var year: String
init {
this.title = title!!
this.genre = genre!!
this.year = year!!
}
fun getTitle(): String? {
return title
}
fun setTitle(name: String?) {
title = name!!
}
fun getYear(): String? {
return year
}
fun setYear(year: String?) {
this.year = year!!
}
fun getGenre(): String? {
return genre
}
fun setGenre(genre: String?) {
this.genre = genre!!
}
}步骤 5 − 创建一个新的类 MoviesAdapter.kt 并添加以下代码 −
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import androidx.annotation.NonNull
import androidx.recyclerview.widget.RecyclerView
internal class MoviesAdapter(private var moviesList: List<MovieModel>) :
RecyclerView.Adapter<MoviesAdapter.MyViewHolder>() {
internal inner class MyViewHolder(view: View) : RecyclerView.ViewHolder(view) {
var title: TextView = view.findViewById(R.id.title)
var year: TextView = view.findViewById(R.id.year)
var genre: TextView = view.findViewById(R.id.genre)
}
@NonNull
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
val itemView = LayoutInflater.from(parent.context)
.inflate(R.layout.movie_list, parent, false)
return MyViewHolder(itemView)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
val movie = moviesList[position]
holder.title.text = movie.getTitle()
holder.genre.text = movie.getGenre()
holder.year.text = movie.getYear()
}
override fun getItemCount(): Int {
return moviesList.size
}
}步骤 6 − 创建一个布局资源文件 item_row.xml 并添加以下内容 −
<?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" android:layout_width="match_parent" android:layout_height="100dp" android:layout_margin="8dp" app:cardBackgroundColor="@android:color/holo_red_dark"> <RelativeLayout android:layout_width="match_parent" android:layout_height="match_parent" android:padding="8dp"> <TextView android:id="@+id/title" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentStart="true" android:layout_toStartOf="@+id/year" android:textColor="@android:color/white" android:textSize="16sp" android:textStyle="bold" /> <TextView android:id="@+id/year" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentEnd="true" android:textColor="@android:color/white" /> <TextView android:id="@+id/genre" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:textColor="@android:color/white" /> </RelativeLayout> </androidx.cardview.widget.CardView>
步骤 7 − 将以下代码添加到 androidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.q11"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
让我们尝试运行您的应用程序。我假设您已将您的实际 Android 移动设备连接到您的计算机。要从 Android Studio 运行应用程序,请打开您的一个项目活动文件并单击运行图标
工具栏中的。选择您的移动设备作为选项,然后检查您的移动设备,它将显示您的默认屏幕

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