简单介绍
RecylerView能够灵活地实现大数据集的展示,视图的复用管理比ListView更好,能够显示列表,网格,瀑布流等形式,且不同的ViewHolder能够实现item多元化的功能.
使用准备，添加依赖
implementation 'androidx.recyclerview:recyclerview:1.1.0'
下列例子所有依赖
dependencies {
implementation 'androidx.appcompat:appcompat:1.2.0'
implementation 'com.google.android.material:material:1.3.0'
implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
testImplementation 'junit:junit:4.+'
androidTestImplementation 'androidx.test.ext:junit:1.1.2'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
implementation 'androidx.recyclerview:recyclerview:1.1.0'
}
RecyclerView 的简单使用
一:RecyclerView 的初始化
recyclerView = findViewById(R.id.recycler1);
recyclerView.setLayoutManager(new LinearLayoutManager(LinearRecycleActivity.this));
//recyclerView.setAdapter(new CLinearAdapter(LinearRecycleActivity.this));简单使用
recyclerView.setAdapter(new CLinearAdapter(LinearRecycleActivity.this, new CLinearAdapter.onItemClickListener() {
@Override
public void click(int pos) {
Toast.makeText(LinearRecycleActivity.this,"InActivity cilik is "+pos,Toast.LENGTH_SHORT).show();
}
}));//这里嵌入了一个lambda表达式，用于实现监听功能
//xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
android:padding="50dp">
<Button
android:id="@+id/btn_toListView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="toListView"
android:textAllCaps="false"/>
</LinearLayout>
public class CLinearAdapter extends RecyclerView.Adapter <CLinearAdapter.LinearViewHolder>{
private Context context;
private onItemClickListener listener;
CLinearAdapter(Context context,onItemClickListener listener){
this.context = context;
this.listener = listener;
}
@Override
public CLinearAdapter.LinearViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
LinearViewHolder linearViewHolder = new LinearViewHolder(LayoutInflater.from(context).inflate(R.layout.linear_item,parent,false));
return linearViewHolder;
}
@Override
public void onBindViewHolder(@NonNull CLinearAdapter.LinearViewHolder holder, int position) {
//设置item
holder.textView.setText("onBindViewHolder");
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {//点击事件
// Toast.makeText(context,"inAdapter onClick is "+position,Toast.LENGTH_SHORT).show();
listener.click(position);
}
});
}
@Override
public int getItemCount() {
return 20;
}//设置item的个数
class LinearViewHolder extends RecyclerView.ViewHolder{//item的样式
TextView textView;
public LinearViewHolder(@NonNull View itemView) {
super(itemView);
textView = itemView.findViewById(R.id.linear_text);
}
}
public interface onItemClickListener{//给外部的接口,以实现点击事件
void click(int pos);
}
}
//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="wrap_content"
android:padding="10dp"
android:background="#ffffff">
<TextView
android:gravity="center"
android:text="hello"
android:id="@+id/linear_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="25dp" />
</LinearLayout>
这里体现了一个RecyclerView 和 ListView的不同点:在ListView中,可以直接调用监听事件,但RecyclerView需要自己去定义实现监听
public class HorRecyleActivity extends AppCompatActivity {
private RecyclerView recyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_hor);
recyclerView = findViewById(R.id.recycler_hor);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(HorRecyleActivity.this);
linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
recyclerView.setLayoutManager(linearLayoutManager);
recyclerView.setAdapter(new CLinearAdapter(HorRecyleActivity.this, new CLinearAdapter.onItemClickListener() {
@Override
public void click(int pos) {
Toast.makeText(HorRecyleActivity.this,"InActivity cilik is "+pos,Toast.LENGTH_SHORT).show();
}
}));
}
}
public class GridRecyleActivity extends AppCompatActivity {
private RecyclerView recyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_grid_recyle);
recyclerView = findViewById(R.id.recycler_grid);
recyclerView.setLayoutManager(new GridLayoutManager(GridRecyleActivity.this,5));//一行5个
recyclerView.setAdapter(new CLinearAdapter(GridRecyleActivity.this, new CLinearAdapter.onItemClickListener() {
@Override
public void click(int pos) {
Toast.makeText(GridRecyleActivity.this,"InActivity cilik is "+pos,Toast.LENGTH_SHORT).show();
}
}));
}
}
public class FallRecyleActivity2 extends AppCompatActivity {
private RecyclerView recyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fall_recyle2);
recyclerView = findViewById(R.id.recycler_fall);
recyclerView.setLayoutManager(new StaggeredGridLayoutManager(5,StaggeredGridLayoutManager.VERTICAL));//5列
recyclerView.setAdapter(new CLinearAdapter(FallRecyleActivity2.this, new CLinearAdapter.onItemClickListener() {
@Override
public void click(int pos) {
Toast.makeText(FallRecyleActivity2.this,"InActivity cilik is "+pos,Toast.LENGTH_SHORT).show();
}
}));
}
}
//Adpater继承的对象不同
public class StaggerdAdapter extends RecyclerView.Adapter <StaggerdAdapter.LinearViewHolder>{
public class CLinearAdapter extends RecyclerView.Adapter <RecyclerView.ViewHolder>{
private Context context;
private onItemClickListener listener;
CLinearAdapter(Context context,onItemClickListener listener){
this.context = context;
this.listener = listener;
}
@Override
public int getItemViewType(int position){
return position&1;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
if(viewType==1) {
LinearViewHolder linearViewHolder = new LinearViewHolder(LayoutInflater.from(context).inflate(R.layout.linear_item,parent,false));
return linearViewHolder;
}
else {
LinearViewHolder2 linearViewHolder = new LinearViewHolder2(LayoutInflater.from(context).inflate(R.layout.linear2_item,parent,false));
return linearViewHolder;
}
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder,final int position) {
//设置item
if(getItemViewType(position)==1){
((LinearViewHolder)holder).textView.setText("onBindViewHolder1");
}else{
((LinearViewHolder2)holder).textView.setText("onBindViewHolder2");
}
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {//点击事件
// Toast.makeText(context,"inAdapter onClick is "+position,Toast.LENGTH_SHORT).show();
listener.click(position);
}
});
}
@Override
public int getItemCount() {
return 20;
}//设置item的个数
class LinearViewHolder extends RecyclerView.ViewHolder{//item的样式
TextView textView;
public LinearViewHolder(@NonNull View itemView) {
super(itemView);
textView = itemView.findViewById(R.id.linear_text);
}
}
class LinearViewHolder2 extends RecyclerView.ViewHolder{//item的样式
TextView textView;
public LinearViewHolder2(@NonNull View itemView) {
super(itemView);
textView = itemView.findViewById(R.id.linear_text2);
}
}
public interface onItemClickListener{//给外部的接口
void click(int pos);
}
}