RecyclerView的用法

这是一个RecyclerView 的一个最简单实例

如果当前的APP还不支持RecyclerView那么需要配置一下，在build.gradle 文件里面添加

implementation 'androidx.recyclerview:recyclerview:1.1.0'

 

RecyclerActivity.java文件

public class RecyclerActivity extends AppCompatActivity {
    private RecyclerView recyclerView;
    private ArrayList<String> mDatas = new ArrayList<>();

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.recycler_activity);
        recyclerView = (RecyclerView) findViewById(R.id.recyclerview);

        for(int i=0 ; i<120 ; i++){
            mDatas.add("第"+i+"个");
        }
        //System.out.println(mDatas);
        //设置垂直滚动或者水平滚动
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        recyclerView.setLayoutManager(linearLayoutManager);
        MyAdapter myAdapter = new MyAdapter(this,mDatas);
        recyclerView.setAdapter(myAdapter);

    }
}

 

补充：如果要实现为网格的布局则将上面的垂直滚动替换为，这是4列的布局

//设置成为4列
GridLayoutManager gridLayoutManager = new GridLayoutManager(this,4);
recyclerView.setLayoutManager(gridLayoutManager);

 

recycler_activity  xml文件，在这个文件中创建了RecyclerView标签

<?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:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="recyclerView"
        android:textSize="18sp"
        android:gravity="center"
        />

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerview"
        android:layout_height="0dp"
        android:layout_width="match_parent"
        android:layout_weight="1"
        >
    </androidx.recyclerview.widget.RecyclerView>

</LinearLayout>

接下来创建Adapter文件 MyAdapter.java

public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private Context mContext;
    private ArrayList<String> mData;

    public MyAdapter(Context context,ArrayList<String> datas){
        this.mContext = context;
        this.mData = datas;

    }

    @NonNull
    @Override
    //该方法用于创建列表项组件。使用该方法创建的组件会被自动缓存。
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(mContext).inflate(R.layout.recycler_item_1,parent,false);
        return new NormalHolder(view);
    }

    @Override
    //该方法负责为列表项组件绑定数据，每次组件重新显示出来都会执行该方法
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        NormalHolder normalHolder = (NormalHolder) holder;
        normalHolder.mTV.setText(mData.get(position));
    }

    @Override
    //该方法的返回值决定包含多少个列表项
    public int getItemCount() {
        return mData.size();
    }

    public class NormalHolder extends RecyclerView.ViewHolder{
        public TextView mTV;
        public NormalHolder(@NonNull View itemView) {
            super(itemView);
            mTV = (TextView) itemView.findViewById(R.id.tv_item_1);
        }
    }
}

在MyAdapter文件中 recycler_item_1作为一个列表项

<?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="wrap_content">
    <TextView
        android:id="@+id/tv_item_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="recycler_item"
        />
</LinearLayout>

 

好了，这就是一个简单的RecyclerView 实例的全部代码。