我用Android的RecyclerView做过几次物品列表，但这是一个相当复杂的过程。浏览众多在线教程中的一个作品(这个，这个，这个都很好)，但我正在寻找一个简单的示例，我可以复制和粘贴来快速启动和运行。只需要以下特性:
垂直布局 每行都有一个单一的TextView 响应点击事件
因为这个愿望我已经许过好几次了，所以我最终决定把答案写在下面，供我和你们将来参考。
当前回答
首先添加recyclerview库。
implementation 'androidx.recyclerview:recyclerview:1.1.0'
创建模型类。
public class UserModel implements Serializable {
private String userName;
public UserModel(String userName) {
this.userName = userName;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
}
创建适配器类。
public class UsersAdapter extends RecyclerView.Adapter<UsersAdapter.UsersAdapterVh> implements Filterable {
private List<UserModel> userModelList;
private List<UserModel> getUserModelListFiltered;
private Context context;
private SelectedUser selectedUser;
public UsersAdapter(List<UserModel> userModelList,SelectedUser selectedUser) {
this.userModelList = userModelList;
this.getUserModelListFiltered = userModelList;
this.selectedUser = selectedUser;
}
@NonNull
@Override
public UsersAdapter.UsersAdapterVh onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
context = parent.getContext();
return new UsersAdapterVh(LayoutInflater.from(context).inflate(R.layout.row_users,null));
}
@Override
public void onBindViewHolder(@NonNull UsersAdapter.UsersAdapterVh holder, int position) {
UserModel userModel = userModelList.get(position);
String username = userModel.getUserName();
String prefix = userModel.getUserName().substring(0,1);
holder.tvUsername.setText(username);
holder.tvPrefix.setText(prefix);
}
@Override
public int getItemCount() {
return userModelList.size();
}
@Override
public Filter getFilter() {
Filter filter = new Filter() {
@Override
protected FilterResults performFiltering(CharSequence charSequence) {
FilterResults filterResults = new FilterResults();
if(charSequence == null | charSequence.length() == 0){
filterResults.count = getUserModelListFiltered.size();
filterResults.values = getUserModelListFiltered;
}else{
String searchChr = charSequence.toString().toLowerCase();
List<UserModel> resultData = new ArrayList<>();
for(UserModel userModel: getUserModelListFiltered){
if(userModel.getUserName().toLowerCase().contains(searchChr)){
resultData.add(userModel);
}
}
filterResults.count = resultData.size();
filterResults.values = resultData;
}
return filterResults;
}
@Override
protected void publishResults(CharSequence charSequence, FilterResults filterResults) {
userModelList = (List<UserModel>) filterResults.values;
notifyDataSetChanged();
}
};
return filter;
}
public interface SelectedUser{
void selectedUser(UserModel userModel);
}
public class UsersAdapterVh extends RecyclerView.ViewHolder {
TextView tvPrefix;
TextView tvUsername;
ImageView imIcon;
public UsersAdapterVh(@NonNull View itemView) {
super(itemView);
tvPrefix = itemView.findViewById(R.id.prefix);
tvUsername = itemView.findViewById(R.id.username);
imIcon = itemView.findViewById(R.id.imageView);
itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
selectedUser.selectedUser(userModelList.get(getAdapterPosition()));
}
});
}
}
}
创建布局row_uses.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="match_parent"
android:padding="10dp"
android:layout_height="wrap_content">
<RelativeLayout
android:layout_width="50dp"
android:background="@drawable/users_bg"
android:layout_height="50dp">
<TextView
android:id="@+id/prefix"
android:layout_width="wrap_content"
android:textSize="16sp"
android:textColor="@color/headerColor"
android:text="T"
android:layout_centerInParent="true"
android:layout_height="wrap_content"/>
</RelativeLayout>
<TextView
android:id="@+id/username"
android:layout_width="wrap_content"
android:textSize="16sp"
android:textColor="@color/headerColor"
android:text="username"
android:layout_marginStart="90dp"
android:layout_centerVertical="true"
android:layout_height="wrap_content"/>
<ImageView
android:layout_width="wrap_content"
android:id="@+id/imageView"
android:layout_margin="10dp"
android:layout_alignParentEnd="true"
android:src="@drawable/ic_navigate_next_black_24dp"
android:layout_height="wrap_content"/>
</RelativeLayout>
</LinearLayout>
查找recyclerview并填充数据。
Toolbar toolbar;
RecyclerView recyclerView;
List<UserModel> userModelList = new ArrayList<>();
String[] names = {"Richard","Alice","Hannah","David"};
UsersAdapter usersAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView = findViewById(R.id.recyclerview);
toolbar = findViewById(R.id.toolbar);
this.setSupportActionBar(toolbar);
this.getSupportActionBar().setTitle("");
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL));
for(String s:names){
UserModel userModel = new UserModel(s);
userModelList.add(userModel);
}
usersAdapter = new UsersAdapter(userModelList,this);
recyclerView.setAdapter(usersAdapter);
}
在这里找到完整的教程和源代码:
Android RecyclerView
其他回答
最小化回收器视图准备使用Kotlin模板:
垂直布局 每行都有一个单一的TextView 响应点击事件(Single和LongPress)
我知道这是一个旧的线程，所以在这里回答。添加以下答案以供将来参考:
在构建依赖项中添加回收视图
implementation 'com.google.android.material:material:1.4.0-alpha02'
// RecyclerView
implementation "androidx.recyclerview:recyclerview:1.2.0"
在布局中添加一个循环视图
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/wifiList"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
创建一个显示列表项的布局(list_item.xml)
<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:padding="5dp"
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="wrap_content">
<androidx.appcompat.widget.AppCompatTextView
android:id="@+id/ssid"
android:text="@string/app_name"
android:layout_width="match_parent"
android:textSize="17sp"
android:layout_height="wrap_content" />
</LinearLayout>
</androidx.cardview.widget.CardView>
现在创建一个最小的适配器来保存数据，这里的代码不言自明
class WifiAdapter(private val wifiList: ArrayList<ScanResult>) : RecyclerView.Adapter<WifiAdapter.ViewHolder>() {
// holder class to hold reference
inner class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
//get view reference
var ssid: TextView = view.findViewById(R.id.ssid) as TextView
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
// create view holder to hold reference
return ViewHolder( LayoutInflater.from(parent.context).inflate(R.layout.list_item, parent, false))
}
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
//set values
holder.ssid.text = wifiList[position].SSID
}
override fun getItemCount(): Int {
return wifiList.size
}
// update your data
fun updateData(scanResult: ArrayList<ScanResult>) {
wifiList.clear()
notifyDataSetChanged()
wifiList.addAll(scanResult)
notifyDataSetChanged()
}
}
添加这个类来处理列表项上的单点和长点事件
import android.content.Context;
import androidx.recyclerview.widget.RecyclerView
import androidx.recyclerview.widget.RecyclerView.OnItemTouchListener
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
public class RecyclerTouchListener implements RecyclerView.OnItemTouchListener {
public interface ClickListener {
void onClick(View view, int position);
void onLongClick(View view, RecyclerView recyclerView, int position);
}
private GestureDetector gestureDetector;
private ClickListener clickListener;
public RecyclerTouchListener(Context context, final RecyclerView recyclerView, final ClickListener clickListener) {
this.clickListener = clickListener;
gestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onSingleTapUp(MotionEvent e) {
return true;
}
@Override
public void onLongPress(MotionEvent e) {
View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
if (child != null && clickListener != null) {
clickListener.onLongClick(child,recyclerView, recyclerView.getChildPosition(child));
}
}
});
}
@Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
View child = rv.findChildViewUnder(e.getX(), e.getY());
if (child != null && clickListener != null && gestureDetector.onTouchEvent(e)) {
clickListener.onClick(child, rv.getChildPosition(child));
}
return false;
}
@Override
public void onTouchEvent(RecyclerView rv, MotionEvent e) {
}
@Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
}
最后，将适配器设置为回收器视图，并添加触摸侦听器，以开始拦截单次或双击列表项的触摸事件
wifiAdapter = WifiAdapter(ArrayList())
wifiList.apply {
// vertical layout
layoutManager = LinearLayoutManager(applicationContext)
// set adapter
adapter = wifiAdapter
// Touch handling
wifiList.addOnItemTouchListener(RecyclerTouchListener(applicationContext, wifiList, object : RecyclerTouchListener.ClickListener {
override fun onClick(view: View?, position: Int) {
Toast.makeText(applicationContext, "RV OnCLickj " + position, Toast.LENGTH_SHORT).show()
}
override fun onLongClick(view: View, recyclerView: RecyclerView, position: Int) {
Toast.makeText(applicationContext, "RV OnLongCLickj " + position, Toast.LENGTH_SHORT).show()
}
}
))
}
奖励:更新数据
wifiAdapter.updateData(mScanResults as ArrayList<ScanResult>)
结果:
我很高兴我不是唯一一个认为这些“最小”示例都涉及创建至少4个不同文件来创建一个简单工具的人。
下面是Kotlin中的一个独立活动(基于Saifur Rahman Mohsin的回答)，它实现了一个基本的回收器视图:
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.constraintlayout.widget.ConstraintLayout
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
class ModelDownloaderActivity : AppCompatActivity() {
val items = (1..50).toList().map { "Item #$it" }
inner class ItemHolder(view: View, var textField: TextView = view.findViewById(android.R.id.text1)) : RecyclerView.ViewHolder(view)
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
// Create recycler view, or find it in Activity's XML file if you prefer
val myLayoutResource: Int? = null // Replace with R.layout.activity_model_downloader if you want to use an XML layout with a recycler view in it
val recyclerView = myLayoutResource?.let {
setContentView(it)
findViewById(R.id.modelRecyclerView) // Replace with ID of your recycler view in layout
} ?: RecyclerView(this).also { setContentView(ConstraintLayout(this).apply { addView(it) }) }
// Bind controls to it.
recyclerView.layoutManager = LinearLayoutManager(this)
recyclerView.adapter = object : RecyclerView.Adapter<ItemHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =
ItemHolder(LayoutInflater.from(parent.context).inflate(android.R.layout.simple_list_item_1, parent, false))
override fun getItemCount() = items.size
override fun onBindViewHolder(holder: ItemHolder, position: Int) {
holder.textField.text = items[position]
holder.textField.setOnClickListener {
Toast.makeText(this@ModelDownloaderActivity, "Clicked $position", Toast.LENGTH_SHORT).show()
}
}
}
}
}
这里有一个更新的Kotlin解决方案，它比这里写的许多答案要简单得多，它使用匿名类。
val items = mutableListOf<String>()
inner class ItemHolder(view: View): RecyclerView.ViewHolder(view) {
var textField: TextView = view.findViewById(android.R.id.text1) as TextView
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
rvitems.layoutManager = LinearLayoutManager(context)
rvitems.adapter = object : RecyclerView.Adapter<ItemHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ItemHolder {
return ItemHolder(LayoutInflater.from(parent.context).inflate(android.R.layout.simple_list_item_1, parent, false))
}
override fun getItemCount(): Int {
return items.size
}
override fun onBindViewHolder(holder: ItemHolder, position: Int) {
holder.textField.text = items[position]
holder.textField.setOnClickListener {
Toast.makeText(context, "Clicked $position", Toast.LENGTH_SHORT).show()
}
}
}
}
我擅自使用了android.R.layout。Simple_list_item_1因为它更简单。我想进一步简化它，并将ItemHolder作为一个内部类，但不太清楚如何在外部类参数的类型中引用它。
您可以使用带有diff utils和过滤器的抽象适配器
SimpleAbstractAdapter.kt
abstract class SimpleAbstractAdapter<T>(private var items: ArrayList<T> = arrayListOf()) : RecyclerView.Adapter<SimpleAbstractAdapter.VH>() {
protected var listener: OnViewHolderListener<T>? = null
private val filter = ArrayFilter()
private val lock = Any()
protected abstract fun getLayout(): Int
protected abstract fun bindView(item: T, viewHolder: VH)
protected abstract fun getDiffCallback(): DiffCallback<T>?
private var onFilterObjectCallback: OnFilterObjectCallback? = null
private var constraint: CharSequence? = ""
override fun onBindViewHolder(vh: VH, position: Int) {
getItem(position)?.let { bindView(it, vh) }
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): VH {
return VH(parent, getLayout())
}
override fun getItemCount(): Int = items.size
protected abstract class DiffCallback<T> : DiffUtil.Callback() {
private val mOldItems = ArrayList<T>()
private val mNewItems = ArrayList<T>()
fun setItems(oldItems: List<T>, newItems: List<T>) {
mOldItems.clear()
mOldItems.addAll(oldItems)
mNewItems.clear()
mNewItems.addAll(newItems)
}
override fun getOldListSize(): Int {
return mOldItems.size
}
override fun getNewListSize(): Int {
return mNewItems.size
}
override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
return areItemsTheSame(
mOldItems[oldItemPosition],
mNewItems[newItemPosition]
)
}
abstract fun areItemsTheSame(oldItem: T, newItem: T): Boolean
override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
return areContentsTheSame(
mOldItems[oldItemPosition],
mNewItems[newItemPosition]
)
}
abstract fun areContentsTheSame(oldItem: T, newItem: T): Boolean
}
class VH(parent: ViewGroup, @LayoutRes layout: Int) : RecyclerView.ViewHolder(LayoutInflater.from(parent.context).inflate(layout, parent, false))
interface OnViewHolderListener<T> {
fun onItemClick(position: Int, item: T)
}
fun getItem(position: Int): T? {
return items.getOrNull(position)
}
fun getItems(): ArrayList<T> {
return items
}
fun setViewHolderListener(listener: OnViewHolderListener<T>) {
this.listener = listener
}
fun addAll(list: List<T>) {
val diffCallback = getDiffCallback()
when {
diffCallback != null && !items.isEmpty() -> {
diffCallback.setItems(items, list)
val diffResult = DiffUtil.calculateDiff(diffCallback)
items.clear()
items.addAll(list)
diffResult.dispatchUpdatesTo(this)
}
diffCallback == null && !items.isEmpty() -> {
items.clear()
items.addAll(list)
notifyDataSetChanged()
}
else -> {
items.addAll(list)
notifyDataSetChanged()
}
}
}
fun add(item: T) {
items.add(item)
notifyDataSetChanged()
}
fun add(position:Int, item: T) {
items.add(position,item)
notifyItemInserted(position)
}
fun remove(position: Int) {
items.removeAt(position)
notifyItemRemoved(position)
}
fun remove(item: T) {
items.remove(item)
notifyDataSetChanged()
}
fun clear(notify: Boolean=false) {
items.clear()
if (notify) {
notifyDataSetChanged()
}
}
fun setFilter(filter: SimpleAdapterFilter<T>): ArrayFilter {
return this.filter.setFilter(filter)
}
interface SimpleAdapterFilter<T> {
fun onFilterItem(contains: CharSequence, item: T): Boolean
}
fun convertResultToString(resultValue: Any): CharSequence {
return filter.convertResultToString(resultValue)
}
fun filter(constraint: CharSequence) {
this.constraint = constraint
filter.filter(constraint)
}
fun filter(constraint: CharSequence, listener: Filter.FilterListener) {
this.constraint = constraint
filter.filter(constraint, listener)
}
fun getFilter(): Filter {
return filter
}
interface OnFilterObjectCallback {
fun handle(countFilterObject: Int)
}
fun setOnFilterObjectCallback(objectCallback: OnFilterObjectCallback) {
onFilterObjectCallback = objectCallback
}
inner class ArrayFilter : Filter() {
private var original: ArrayList<T> = arrayListOf()
private var filter: SimpleAdapterFilter<T> = DefaultFilter()
private var list: ArrayList<T> = arrayListOf()
private var values: ArrayList<T> = arrayListOf()
fun setFilter(filter: SimpleAdapterFilter<T>): ArrayFilter {
original = items
this.filter = filter
return this
}
override fun performFiltering(constraint: CharSequence?): Filter.FilterResults {
val results = Filter.FilterResults()
if (constraint == null || constraint.isBlank()) {
synchronized(lock) {
list = original
}
results.values = list
results.count = list.size
} else {
synchronized(lock) {
values = original
}
val result = ArrayList<T>()
for (value in values) {
if (constraint!=null && constraint.trim().isNotEmpty() && value != null) {
if (filter.onFilterItem(constraint, value)) {
result.add(value)
}
} else {
value?.let { result.add(it) }
}
}
results.values = result
results.count = result.size
}
return results
}
override fun publishResults(constraint: CharSequence, results: Filter.FilterResults) {
items = results.values as? ArrayList<T> ?: arrayListOf()
notifyDataSetChanged()
onFilterObjectCallback?.handle(results.count)
}
}
class DefaultFilter<T> : SimpleAdapterFilter<T> {
override fun onFilterItem(contains: CharSequence, item: T): Boolean {
val valueText = item.toString().toLowerCase()
if (valueText.startsWith(contains.toString())) {
return true
} else {
val words = valueText.split(" ".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()
for (word in words) {
if (word.contains(contains)) {
return true
}
}
}
return false
}
}
}
并利用实现方法对抽象适配器进行扩展
TasksAdapter.kt
import android.annotation.SuppressLint
import kotlinx.android.synthetic.main.task_item_layout.view.*
class TasksAdapter(private val listener:TasksListener? = null) : SimpleAbstractAdapter<Task>() {
override fun getLayout(): Int {
return R.layout.task_item_layout
}
override fun getDiffCallback(): DiffCallback<Task>? {
return object : DiffCallback<Task>() {
override fun areItemsTheSame(oldItem: Task, newItem: Task): Boolean {
return oldItem.id == newItem.id
}
override fun areContentsTheSame(oldItem: Task, newItem: Task): Boolean {
return oldItem.items == newItem.items
}
}
}
@SuppressLint("SetTextI18n")
override fun bindView(item: Task, viewHolder: VH) {
viewHolder.itemView.apply {
val position = viewHolder.adapterPosition
val customer = item.customer
val customerName = if (customer != null) customer.name else ""
tvTaskCommentTitle.text = customerName + ", #" + item.id
tvCommentContent.text = item.taskAddress
ivCall.setOnClickListener {
listener?.onCallClick(position, item)
}
setOnClickListener {
listener?.onItemClick(position, item)
}
}
}
interface TasksListener : SimpleAbstractAdapter.OnViewHolderListener<Task> {
fun onCallClick(position: Int, item: Task)
}
}
初始化适配器
mAdapter = TasksAdapter(object : TasksAdapter.TasksListener {
override fun onCallClick(position: Int, item:Task) {
}
override fun onItemClick(position: Int, item:Task) {
}
})
rvTasks.adapter = mAdapter
并填写
mAdapter?.addAll(tasks)
添加自定义过滤器
mAdapter?.setFilter(object : SimpleAbstractAdapter.SimpleAdapterFilter<MoveTask> {
override fun onFilterItem(contains: CharSequence, item:Task): Boolean {
return contains.toString().toLowerCase().contains(item.id?.toLowerCase().toString())
}
})
过滤数据
mAdapter?.filter("test")
由于我还不能评论，我将发布一个链接的答案..我在recyclerview上找到了一个简单、组织良好的教程 http://www.androiddeft.com/2017/10/01/recyclerview-android/
除此之外，当你要在你的活动中添加一个回收器视图时，你想做的事情如下所示，你应该如何做，已经在链接中描述了
将RecyclerView组件添加到布局文件中 创建一个要显示为列表行的类 制作一个布局文件，这是你列表中的一行的布局 现在我们需要一个自定义适配器，因此通过扩展来创建一个自定义适配器 从父类RecyclerView。适配器 在mainActivity oncreate中添加recyclerview 添加分隔符 添加Touch监听器
推荐文章
- Manifest合并失败:uses-sdk:minSdkVersion 14
- 为什么Android工作室说“等待调试器”如果我不调试?
- 如何检查我的EditText字段是否为空?
- Android从图库中选择图像
- 后台任务，进度对话框，方向改变-有任何100%工作的解决方案吗?
- Android:垂直对齐多行EditText(文本区域)
- Android无尽列表
- Android room persistent: AppDatabase_Impl不存在
- 错误:执行失败的任务':app:compileDebugKotlin'。>编译错误。详细信息请参见日志
- 在Android中使用URI生成器或使用变量创建URL
- 缩放图像以填充ImageView宽度并保持纵横比
- 列表视图的自定义适配器
- 在Android中设置TextView span的颜色
- 如何以编程方式在RelativeLayout中布局视图?
- Android Facebook集成无效键散列
