入门recyclerView

RecyclerView 使用完全解析 体验艺术般的控件

import android.graphics.Canvas;
import android.graphics.Rect;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private RecyclerView recyclerView;
    private MyAdapter adapter;
    public List<Integer> mHeights;
    public List<String> mDatas;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initData();
        initView();

    }

    private void initView() {
        recyclerView = (RecyclerView) findViewById(R.id.id_recyclerview);
        //recyclerView.setLayoutManager(new LinearLayoutManager(this));
        //recyclerView.setLayoutManager(new GridLayoutManager(this,4));
        recyclerView.setLayoutManager(new StaggeredGridLayoutManager(4,StaggeredGridLayoutManager.VERTICAL));

        adapter = new MyAdapter();
        recyclerView.setAdapter(adapter);

        //recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));
        recyclerView.addItemDecoration(new DividerGridItemDecoration(this));
    }


    private void initData() {
        mDatas = new ArrayList<String>();
        for (int i = 'A';i < 'z';i++){
            mDatas.add("" + (char)i);
        }
        mHeights = new ArrayList<>();
        for (int i = 0;i<mDatas.size();i++){
            mHeights.add((int) (100 + Math.random()*300));
        }

    }
/**
 * 1.适配器实现专门的RecyclerView的adapter
 * 2.传入一个viewHolder对象(一般是自己定义)
 * 3.创建一个自己类MyViewHolder实现Viewholder
 * 4.MyViewHolder得到的就是item中的布局，并实例化组件
 * 5.onCreateViewHolder中实例化自己的holder对象,并返回给onBindViewHolder
 * 6.onBindViewHolder()中通过holder对象来使用item中的组件
 */

    class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder>{

        @Override
        public MyAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

            MyViewHolder holder = new MyViewHolder(LayoutInflater.from(MainActivity.this)
                    .inflate(R.layout.layout,parent,false));

            return holder;
        }

        @Override
        public void onBindViewHolder(MyAdapter.MyViewHolder holder, int position) {

            ViewGroup.LayoutParams layoutParams = holder.itemView.getLayoutParams();
            layoutParams.height = mHeights.get(position);
            holder.itemView.setLayoutParams(layoutParams);
            holder.tv.setText(mDatas.get(position));

        }

        @Override
        public int getItemCount() {
            return mDatas.size();
        }


        class MyViewHolder extends RecyclerView.ViewHolder {

        TextView tv;
        public MyViewHolder(View itemView) {
            super(itemView);
            tv = itemView.findViewById(R.id.id_num);
        }
    }

    }
}

最终效果如图