android基础学习【六、控件（RecyclerView）】

RecyclerView

在使用该控件之前，需要在build.gradle中添加如下代码：

implementation 'androidx.recyclerview:recyclerview:1.1.0'

与ListView不同：

1. 可以自定义布局
2. 需要写监听接口
3. 需要定义MyViewHolder
   MainActivity.java

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 < 100; i++) {
            Bean bean = new Bean();
            bean.setName("st" + i);
            data.add(bean);
        }

        RecyclerView recyclerView = findViewById(R.id.rv);

        //自定义布局(网格布局)
        GridLayoutManager gridLayoutManager = new GridLayoutManager(this,3);
        recyclerView.setLayoutManager(gridLayoutManager);

        MyAdapter myAdapter = new MyAdapter(data,this);
        recyclerView.setAdapter(myAdapter);

        //设置监听
        myAdapter.setOnItemClickListener(new MyAdapter.OnRecyclerItemClickListener() {
            @Override
            public void onRecyclerItemClick(int position) {
                Log.e("kl","onRecyclerItemClick" + position);
            }
        });
    }
}

MyAdapter.java

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> data, Context context) {
        this.data = data;
        this.context = context;
    }

    @NonNull
    @Override
    public MyAdapter.MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = View.inflate(context,R.layout.recyclerview_item,null);
        return new MyViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull MyAdapter.MyViewHolder holder, int position) {
        holder.tv.setText(data.get(position).getName());
    }

    @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.tv);

            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(mOnItemClickListener != null){
                        mOnItemClickListener.onRecyclerItemClick(getAdapterPosition());
                    }
                }
            });

        }
    }

    private OnRecyclerItemClickListener mOnItemClickListener;

    public void setOnItemClickListener(OnRecyclerItemClickListener listener){
        mOnItemClickListener = listener;
    }

    public  interface OnRecyclerItemClickListener{
        void onRecyclerItemClick(int position);
    }

}