public class MainActivity extends AppCompatActivity implements View.OnClickListener{  private Button mButton1;  private Button mButton2;  private Button mButton3;  private Button mButton4;  private Button mButton5;  private RecyclerView mRecyclerView;  private ArrayList<String> mList;  private LinearLayoutManager mLinearLayoutManager;  private RvAdapter mAdapter;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    findViews();    mList = new ArrayList<>();    for (int i=0;i<20;i++){      mList.add(i+"item");    }    mAdapter = new RvAdapter(mList, this);    mRecyclerView.setAdapter(mAdapter);    //設置分割線    mRecyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL));    //設置默認布局    mLinearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);    mRecyclerView.setLayoutManager(mLinearLayoutManager);    mAdapter.setOnItemClickListener(new RvAdapter.OnItemClickListener() {      @Override      public void onItemClick(int position) {        mAdapter.remove(position);      }      @Override      public void onItemLongClick(int position) {        mAdapter.remove(position);      }    });  }  private void findViews() {    mRecyclerView = findViewById(R.id.rv);    mButton1= findViewById(R.id.b1);    mButton2= findViewById(R.id.b2);    mButton3= findViewById(R.id.b3);    mButton4= findViewById(R.id.b4);    mButton5= findViewById(R.id.b5);    mButton1.setOnClickListener(this);    mButton2.setOnClickListener(this);    mButton3.setOnClickListener(this);    mButton4.setOnClickListener(this);    mButton5.setOnClickListener(this);  }  @Override  public void onClick(View view) {    switch (view.getId()){      case R.id.b1:        mAdapter.addData(3);        mRecyclerView.scrollToPosition(0);        break;      case R.id.b2:        mAdapter.remove(mList.size()-1);        break;      case R.id.b3:        mLinearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);        mRecyclerView.setLayoutManager(mLinearLayoutManager);        break;      case R.id.b4:        mRecyclerView.setLayoutManager(new GridLayoutManager(this, 3));        //mRecyclerView.addItemDecoration(new android.support.v7.widget.DividerItemDecoration(this, DividerItemDecoration.HORIZONTAL));        break;      case R.id.b5:        mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL));        break;    }  }}

<android.support.constraint.ConstraintLayout 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">  <LinearLayout    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical">    <LinearLayout      android:layout_width="match_parent"      android:layout_height="wrap_content"      android:orientation="horizontal">      <Button        android:id="@+id/b1"        android:layout_width="wrap_content"        android:layout_weight="1"        android:layout_height="wrap_content"        android:text="添加"/>      <Button        android:id="@+id/b2"        android:layout_width="wrap_content"        android:layout_weight="1"        android:layout_height="wrap_content"        android:text="刪除"/>      <Button        android:id="@+id/b3"        android:layout_width="wrap_content"        android:layout_weight="1"        android:layout_height="wrap_content"        android:text="List"/>      <Button        android:id="@+id/b4"        android:layout_width="wrap_content"        android:layout_weight="1"        android:layout_height="wrap_content"        android:text="Grid"/>      <Button        android:id="@+id/b5"        android:layout_width="wrap_content"        android:layout_weight="1"        android:layout_height="wrap_content"        android:text="flow"/>    </LinearLayout>    <android.support.v7.widget.RecyclerView      android:id="@+id/rv"      android:layout_width="match_parent"      android:layout_height="match_parent"/>  </LinearLayout></android.support.constraint.ConstraintLayout>

public class RvAdapter extends RecyclerView.Adapter<RvAdapter.ViewHolder>{  private List<String> lists;  private Context mContext;  public RvAdapter(List<String> lists, Context context) {    this.lists = lists;    mContext = context;  }  @Override  public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {    View view = View.inflate(mContext, R.layout.item, null);    ViewHolder holder = new ViewHolder(view);    return holder;  }  public void addData(int position) {    lists.add(position,"ff");    notifyItemInserted(position);  }  public void remove(int i) {    lists.remove(i);    notifyItemRemoved(i);    notifyDataSetChanged();  }  public interface OnItemClickListener{  //自定義接口回調設置點擊事件    void onItemClick(int position);    void onItemLongClick(int position);  }  private OnItemClickListener mOnItemClickListener;  public void setOnItemClickListener(OnItemClickListener onItemClickListener){    mOnItemClickListener=onItemClickListener;  }  @Override  public void onBindViewHolder(final ViewHolder holder, final int position) {    holder.mTextView.setText(lists.get(position));       holder.itemView.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View view) {           int ps = holder.getLayoutPosition();           mOnItemClickListener.onItemClick(ps);         }       });       holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {         @Override         public boolean onLongClick(View view) {           int ps=holder.getLayoutPosition();           mOnItemClickListener.onItemLongClick(ps);           return false;         }       });  }  @Override  public int getItemCount() {    return lists.size();  }  public static class ViewHolder extends RecyclerView.ViewHolder{    public final TextView mTextView;    public ViewHolder(View itemView) {      super(itemView);      mTextView = (TextView) itemView.findViewById(R.id.tv);    }  }}

implementation 'com.android.support:recyclerview-v7:27.1.1'