十七、RecyclerView
一、导入依赖包
dependencies {
//添加 RecyclerView的依赖包
implementation 'androidx.recyclerview:recyclerview:1.2.1'
}
二、代码示例
1.布局页面
<?xml version="1.0" encoding="utf-8"?> <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" xmlns:android="http://schemas.android.com/apk/res/android"> <androidx.recyclerview.widget.RecyclerView android:id="@+id/rv" android:layout_width="match_parent" android:layout_height="match_parent" /> </LinearLayout>
<?xml version="1.0" encoding="utf-8"?> <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" xmlns:android="http://schemas.android.com/apk/res/android"> <TextView android:id="@+id/txt" android:textSize="15sp" android:layout_width="wrap_content" android:layout_height="wrap_content"/> </LinearLayout>
2.后台代码
2.1 创建Bean类
package com.example.myrecyclerview; public class Bean { private String name; public String getName() { return name; } public void setName(String name) { this.name = name; } }
2.2 创建MyAdapter,继承 RecyclerView.Adapter ,需要手动创建实现 item 的点击监听事件
package com.example.myrecyclerview; import android.content.Context; import android.view.View; import android.view.ViewGroup; import android.widget.TextView; import androidx.annotation.NonNull; import androidx.recyclerview.widget.RecyclerView; import java.util.List; public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> { private List<Bean> data; private Context context; public MyAdapter(List<Bean> data1,Context context1) { this.data=data1; this.context=context1; } @NonNull @Override public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { //获取布局 View view = View.inflate(context,R.layout.recycleview_list,null); return new MyViewHolder(view); } @Override public void onBindViewHolder(@NonNull MyViewHolder holder, int position) { holder.tv.setText(data.get(position).getName()); } /** * 显示多少个 * */ @Override public int getItemCount() { return data==null?0:data.size(); } public class MyViewHolder extends RecyclerView.ViewHolder { private TextView tv; public MyViewHolder(@NonNull View itemView) { super(itemView); tv=itemView.findViewById(R.id.txt); //实现监听方法的回调 itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { if (mOnItemClickListener!=null) { mOnItemClickListener.onRecyclerItemClick(getAdapterPosition()); } } }); } } //创建接口 public interface OnRecyclerItemClickListener{ void onRecyclerItemClick(int position); } private OnRecyclerItemClickListener mOnItemClickListener; //创建设置监听的方法 public void setRecyclerItemClickListener(OnRecyclerItemClickListener listener){ mOnItemClickListener = listener; } }
2.3 主程序调用,布局设置(注:瀑布流的显示效果会填充 没有使用的区域),最后实现 setRecyclerItemClickListener 的监听信息,进行item点击的回调显示。
package com.example.myrecyclerview; import androidx.appcompat.app.AppCompatActivity; import androidx.recyclerview.widget.GridLayoutManager; import androidx.recyclerview.widget.LinearLayoutManager; import androidx.recyclerview.widget.RecyclerView; import androidx.recyclerview.widget.StaggeredGridLayoutManager; import android.os.Bundle; import android.util.Log; import android.widget.LinearLayout; import java.util.ArrayList; import java.util.List; public class MainActivity extends AppCompatActivity { private List<Bean> data=new ArrayList<>(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); for (int i=0;i<1000;i++){ Bean bean=new Bean(); bean.setName("享学"+i); data.add(bean); } //实现 RecyclerView RecyclerView recyclerView = findViewById(R.id.rv); //设置布局 //垂直 /*LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this); recyclerView.setLayoutManager(linearLayoutManager);*/ //网格 整齐网格布局 /*GridLayoutManager gridLayoutManager = new GridLayoutManager(this,3); recyclerView.setLayoutManager(gridLayoutManager);*/ //瀑布流 自动填充剩余空间 StaggeredGridLayoutManager staggeredGridLayoutManager = new StaggeredGridLayoutManager(3, LinearLayout.VERTICAL); recyclerView.setLayoutManager(staggeredGridLayoutManager); MyAdapter myAdapter = new MyAdapter(data,this); recyclerView.setAdapter(myAdapter); myAdapter.setRecyclerItemClickListener(new MyAdapter.OnRecyclerItemClickListener() { @Override public void onRecyclerItemClick(int position) { Log.e("tag", "onRecyclerItemClick: "+position ); } }); } }