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
现在，您需要一个适配器来支持所有的RecyclerView
一个适配器可以用于所有的RecyclerView。NO onBindViewHolder, NO onCreateViewHolder处理。 没有从Java/Kotlin类设置适配器的代码。检查样本类。 您可以使用Binding Adapters为每个列表设置事件和自定义数据。
我在这里展示了通过1适配器设置两个不同的RecyclerView
activity_home.xml
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<data>
<variable
name="listOne"
type="java.util.List"/>
<variable
name="listTwo"
type="java.util.List"/>
<variable
name="onItemClickListenerOne"
type="com.ks.nestedrecyclerbindingexample.callbacks.OnItemClickListener"/>
<variable
name="onItemClickListenerTwo"
type="com.ks.nestedrecyclerbindingexample.callbacks.OnItemClickListener"/>
</data>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
rvItemLayout="@{@layout/row_one}"
rvList="@{listOne}"
rvOnItemClick="@{onItemClickListenerOne}"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layoutManager="android.support.v7.widget.LinearLayoutManager"
/>
<android.support.v7.widget.RecyclerView
rvItemLayout="@{@layout/row_two}"
rvList="@{listTwo}"
rvOnItemClick="@{onItemClickListenerTwo}"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layoutManager="android.support.v7.widget.LinearLayoutManager"
/>
</LinearLayout>
</layout>
你可以看到我传递列表，项目布局id和点击listener从布局。
rvItemLayout="@{@layout/row_one}"
rvList="@{listOne}"
rvOnItemClick="@{onItemClickListenerOne}"
该自定义属性由BindingAdapter创建。
public class BindingAdapters {
@BindingAdapter(value = {"rvItemLayout", "rvList", "rvOnItemClick"}, requireAll = false)
public static void setRvAdapter(RecyclerView recyclerView, int rvItemLayout, List rvList, @Nullable OnItemClickListener onItemClickListener) {
if (rvItemLayout != 0 && rvList != null && rvList.size() > 0)
recyclerView.setAdapter(new GeneralAdapter(rvItemLayout, rvList, onItemClickListener));
}
}
从Activity中，你传递list，点击listener like
HomeActivity.java
public class HomeActivity extends AppCompatActivity {
ActivityHomeBinding binding;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = DataBindingUtil.setContentView(this, R.layout.activity_home);
binding.setListOne(new ArrayList()); // pass your list or set list from response of API
binding.setListTwo(new ArrayList());
binding.setOnItemClickListenerOne(new OnItemClickListener() {
@Override
public void onItemClick(View view, Object object) {
if (object instanceof ModelParent) {
// TODO: your action here
}
}
});
binding.setOnItemClickListenerTwo(new OnItemClickListener() {
@Override
public void onItemClick(View view, Object object) {
if (object instanceof ModelChild) {
// TODO: your action here
}
}
});
}
}
你不想读太多，直接克隆/下载完整的例子从我的github回购。你自己试试。
你可以在上面的repo中看到GeneralAdapter.java。
如果您在设置数据绑定时遇到问题，请参阅此回答。
其他回答
这将是RecyclerView实现的最简单版本。
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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=".MainActivity">
<androidx.recyclerview.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/recycler_view"/>
</FrameLayout>
list_item_view.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="46dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/textview"
android:text="TextView"
android:textSize="16dp" />
</LinearLayout>
CustomAdapter.java
public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {
private List<String> data;
public CustomAdapter (List<String> data){
this.data = data;
}
@Override
public CustomAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View rowItem = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_view, parent, false);
return new ViewHolder(rowItem);
}
@Override
public void onBindViewHolder(CustomAdapter.ViewHolder holder, int position) {
holder.textView.setText(this.data.get(position));
}
@Override
public int getItemCount() {
return this.data.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private TextView textView;
public ViewHolder(View view) {
super(view);
view.setOnClickListener(this);
this.textView = view.findViewById(R.id.textview);
}
@Override
public void onClick(View view) {
Toast.makeText(view.getContext(), "position : " + getLayoutPosition() + " text : " + this.textView.getText(), Toast.LENGTH_SHORT).show();
}
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
RecyclerView recyclerView = findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setAdapter(new CustomAdapter(generateData()));
recyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL));
}
private List<String> generateData() {
List<String> data = new ArrayList<>();
for (int i = 0; i < 100; i++) {
data.add(String.valueOf(i) + "th Element");
}
return data;
}
}
现在，您需要一个适配器来支持所有的RecyclerView
一个适配器可以用于所有的RecyclerView。NO onBindViewHolder, NO onCreateViewHolder处理。 没有从Java/Kotlin类设置适配器的代码。检查样本类。 您可以使用Binding Adapters为每个列表设置事件和自定义数据。
我在这里展示了通过1适配器设置两个不同的RecyclerView
activity_home.xml
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<data>
<variable
name="listOne"
type="java.util.List"/>
<variable
name="listTwo"
type="java.util.List"/>
<variable
name="onItemClickListenerOne"
type="com.ks.nestedrecyclerbindingexample.callbacks.OnItemClickListener"/>
<variable
name="onItemClickListenerTwo"
type="com.ks.nestedrecyclerbindingexample.callbacks.OnItemClickListener"/>
</data>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
rvItemLayout="@{@layout/row_one}"
rvList="@{listOne}"
rvOnItemClick="@{onItemClickListenerOne}"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layoutManager="android.support.v7.widget.LinearLayoutManager"
/>
<android.support.v7.widget.RecyclerView
rvItemLayout="@{@layout/row_two}"
rvList="@{listTwo}"
rvOnItemClick="@{onItemClickListenerTwo}"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layoutManager="android.support.v7.widget.LinearLayoutManager"
/>
</LinearLayout>
</layout>
你可以看到我传递列表，项目布局id和点击listener从布局。
rvItemLayout="@{@layout/row_one}"
rvList="@{listOne}"
rvOnItemClick="@{onItemClickListenerOne}"
该自定义属性由BindingAdapter创建。
public class BindingAdapters {
@BindingAdapter(value = {"rvItemLayout", "rvList", "rvOnItemClick"}, requireAll = false)
public static void setRvAdapter(RecyclerView recyclerView, int rvItemLayout, List rvList, @Nullable OnItemClickListener onItemClickListener) {
if (rvItemLayout != 0 && rvList != null && rvList.size() > 0)
recyclerView.setAdapter(new GeneralAdapter(rvItemLayout, rvList, onItemClickListener));
}
}
从Activity中，你传递list，点击listener like
HomeActivity.java
public class HomeActivity extends AppCompatActivity {
ActivityHomeBinding binding;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = DataBindingUtil.setContentView(this, R.layout.activity_home);
binding.setListOne(new ArrayList()); // pass your list or set list from response of API
binding.setListTwo(new ArrayList());
binding.setOnItemClickListenerOne(new OnItemClickListener() {
@Override
public void onItemClick(View view, Object object) {
if (object instanceof ModelParent) {
// TODO: your action here
}
}
});
binding.setOnItemClickListenerTwo(new OnItemClickListener() {
@Override
public void onItemClick(View view, Object object) {
if (object instanceof ModelChild) {
// TODO: your action here
}
}
});
}
}
你不想读太多，直接克隆/下载完整的例子从我的github回购。你自己试试。
你可以在上面的repo中看到GeneralAdapter.java。
如果您在设置数据绑定时遇到问题，请参阅此回答。
首先，在Recycler视图中查看一些内容
回收器视图适配器可以是这样的。
class CustomAdapter: RecyclerView.Adapter<CustomAdapter.ViewHolder>() {
var data = listOf<String>()
set(value) {
field = value
notifyDataSetChanged()
}
override fun getItemCount() =data.size
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
holder.txt.text= data[position]
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
return ViewHolder(
LayoutInflater.from(parent.context).inflate(R.layout.item_view, parent, false)
)
}
class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView){
val txt: TextView = itemView.findViewById(R.id.item_text_view)
}
}
并将适配器附加到回收器视图，并将数据附加到适配器
val view = findViewById<RecyclerView>(R.id.recycler_view)
val adapter = CustomAdapter()
val data = listOf("text1", "text2", "text3")
adapter.data = data
view.layoutManager = LinearLayoutManager(this, RecyclerView.VERTICAL, false)
view.adapter = adapter
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()
}
}
}
}
}
实现androidx.recyclerview: recyclerview:… 建议更新到下面的androidx库:
https://developer.android.com/jetpack/androidx/releases/recyclerview
布局文件Widget XML标签必须更新为: androidx.recyclerview.widget.RecyclerView
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