Android实现可拖拽列表和多选功能

/**
 * 编辑状态下长按拖动条目
 * 1.通过ItemTouchHelper.Callback实现长按拖动
 * 2.通过isEditable的值判断是否编辑状态，初值是false
 * 3.切换编辑状态要把isEditable的值取反，并改变复选框图标状态
 * 4.在编辑状态下，按返回键回到非编辑状态
 * 5.RecyclerView的点击事件通过RecyclerAdapter.Callback实现
 */

public class ReportListActivity extends AppCompatActivity implements View.OnClickListener {

 private static final String TAG = "ReportListActivity";

 @BindView(R.id.tv_title_middle)
 TextView title;
 @BindView(R.id.title_left)
 ImageView backButton;
 @BindView(R.id.online_report_listview)
 RecyclerView mRecyclerView;
 @BindView(R.id.edit_tv)
 TextView edit;
 @BindView(R.id.filter_tv)
 TextView filter;
 @BindView(R.id.btn_delete)
 TextView delete;
 @BindView(R.id.btn_release)
 TextView release;
 @BindView(R.id.btn_close)
 TextView close;
 @BindView(R.id.btn_top)
 TextView top;
 @BindView(R.id.toolbar)
 LinearLayout mToolbar;

 private Context mContext;
 private boolean isEditable;
 private RecyclerAdapter mAdapter;
 private List<ClsOnlineReport> mClsOnlineReportList;
 private ItemTouchHelper itemTouchHelper;

 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_online_report);
  ButterKnife.bind(this);

  initView();
  initData();
  initListener();
 }

 private void initData() {
  mContext = this;

  mClsOnlineReportList = new ArrayList<>();
  mAdapter = new RecyclerAdapter(mClsOnlineReportList);
  mRecyclerView.setAdapter(mAdapter);

  getOfflineData(20);

  //初始状态为非编辑模式
  setIsEditable(false);
  //初始化拖动接口
  OnlineReportListCallback callback = new OnlineReportListCallback(mAdapter);
  itemTouchHelper = new ItemTouchHelper(callback);

  //初始状态为不可拖动
  setRecyclerViewDraggable(false);
 }

 //生成模拟数据
 private void getOfflineData(int num) {
  List<ClsOnlineReport> clsOnlineReportList = new ArrayList<>();
  for (int i = 0; i < num; i++) {
   ClsOnlineReport onlineReport = new ClsOnlineReport();
   onlineReport.setActiveDate("activeDate " + i);
   onlineReport.setAutoCloseDate("autoCloseDate " + i);
   onlineReport.setBulletinID("bulletinID " + i);
   onlineReport.setBulletinTime("bulletinTime " + i);
   onlineReport.setBulletinTitle("bulletinTitle " + i);
   onlineReport.setCreater("creater " + i);
   clsOnlineReportList.add(onlineReport);
  }

  mClsOnlineReportList.addAll(clsOnlineReportList);
  mAdapter.notifyDataSetChanged();
 }

 private void initView() {
  title.setText("可拖拽列表");
  edit.setVisibility(View.VISIBLE);

  mToolbar.setVisibility(View.GONE);
  //设置RecyclerView的布局
  mRecyclerView.setLayoutManager(new LinearLayoutManager(mContext));
 }

 private void initListener() {
  filter.setOnClickListener(this);
  backButton.setOnClickListener(this);
  edit.setOnClickListener(this);
  delete.setOnClickListener(this);
  release.setOnClickListener(this);
  close.setOnClickListener(this);
  top.setOnClickListener(this);


  mAdapter.setmCallback((v, position) -> {
   switch (v.getId()) {
    case R.id.view_parent_1:
    case R.id.view_parent_2:
     ClsOnlineReport clsOnlineReport = mClsOnlineReportList.get(position);

     //在编辑模式下，点击条目切换显示checkbox，并且判断选中条目的数量，
     if (getIsEditable()) {
      if (clsOnlineReport.getIsCheckBoxVisible()) {
       clsOnlineReport.setIsChecked(!clsOnlineReport.getIsChecked());
       mAdapter.notifyDataSetChanged();
      }

      for (int i = 0; i < mClsOnlineReportList.size(); i++) {
       //数量等于0，隐藏工具条，否则显示工具条
       ClsOnlineReport onlineReport = mClsOnlineReportList.get(i);
       if (onlineReport.getIsChecked()) {
        mToolbar.setVisibility(View.VISIBLE);
        break;
       }
       if (i == mClsOnlineReportList.size() - 1) {
        mToolbar.setVisibility(View.GONE);
       }
      }
     } else {
      //在非编辑模式下，点击条目直接跳转详情页，并把bulletinID传过去
      Intent intent = new Intent(mContext, ReportDetailActivity.class);
      intent.putExtra("bulletinID", clsOnlineReport.getBulletinID());
      startActivityForResult(intent, 16371);
     }
   }
  });
 }

 @Override
 public void onBackPressed() {
  //编辑状态下，按返回键回到非编辑状态，否则退出
  if (getIsEditable()) {
   switchEditable();
  } else {
   finish();
  }
 }

 @Override
 public void onClick(View v) {
  //编辑状态下，按返回键回到非编辑状态，否则退出
  if (v.getId() == R.id.title_left) {
   if (getIsEditable()) {
    switchEditable();
   } else {
    finish();
   }
  }
  //点击编辑按钮切换编辑状态
  if (v.getId() == R.id.edit_tv) {
   switchEditable();
  }

  //工具条的按钮对应不同的接口
  switch (v.getId()) {
   case R.id.btn_top:
   case R.id.btn_close:
   case R.id.btn_release:
   case R.id.btn_delete:
    Toast.makeText(mContext, "在此处调用接口", Toast.LENGTH_SHORT).show();
  }

 }

 private void switchEditable() {

  //将属性取反
  setIsEditable(!getIsEditable());

  //遍历列表并赋值
  for (ClsOnlineReport clsOnlineReport : mClsOnlineReportList) {
   clsOnlineReport.setIsCheckBoxVisible(getIsEditable());
   clsOnlineReport.setIsChecked(false);
  }

  //通知适配器刷新
  mAdapter.notifyDataSetChanged();
  //隐藏工具条
  mToolbar.setVisibility(View.GONE);
  //切换拖动状态
  setRecyclerViewDraggable(getIsEditable());
 }

 public boolean getIsEditable() {
  return isEditable;
 }

 public void setIsEditable(boolean isEditable) {
  this.isEditable = isEditable;
 }

 //设置能否拖动
 private void setRecyclerViewDraggable(boolean draggable) {
  if (draggable) {
   itemTouchHelper.attachToRecyclerView(mRecyclerView);
  } else {
   itemTouchHelper.attachToRecyclerView(null);
  }
 }

 @Override
 protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {

  //当详情页的数据有变动则刷新列表
  if (requestCode == 16371 && resultCode == RESULT_OK) {
   refreshData();
  }

  super.onActivityResult(requestCode, resultCode, data);
 }

 private void refreshData() {
  Toast.makeText(mContext, "在此处调用接口", Toast.LENGTH_SHORT).show();
 }
}

/**
 * 可拖拽列表的适配器，
 * 1.需要实现OnlineReportListCallback.ItemTouchMoveListener
 * 2.持有一个接口用于传递position
 */
public class RecyclerAdapter extends RecyclerView.Adapter implements OnlineReportListCallback.ItemTouchMoveListener, View.OnClickListener {

 private List<ClsOnlineReport> mList;
 private Callback mCallback;

 public RecyclerAdapter(List<ClsOnlineReport> mList) {
  this.mList = mList;
 }

 public void setmCallback(Callback mCallback) {
  this.mCallback = mCallback;
 }

 @Override
 public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

  LayoutInflater inflater = LayoutInflater.from(parent.getContext());
  View v = inflater.inflate(R.layout.item_report_list, parent, false);
  return new ItemHolder(v);
 }

 @Override
 public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {

  ClsOnlineReport clsOnlineReport = mList.get(position);
  ItemHolder itemHolder = (ItemHolder) holder;

  if (clsOnlineReport.getIsCheckBoxVisible()) {
   itemHolder.checkbox.setVisibility(View.VISIBLE);
   itemHolder.drag.setVisibility(View.VISIBLE);
  } else {
   itemHolder.checkbox.setVisibility(View.GONE);
   itemHolder.drag.setVisibility(View.GONE);
  }

  if (clsOnlineReport.getIsChecked()) {
   itemHolder.checkbox.setImageResource(R.drawable.ic_check_box_black_24dp);
  } else {
   itemHolder.checkbox.setImageResource(R.drawable.ic_check_box_outline_blank_black_24dp);
  }

  itemHolder.parent1.setTag(position);
  itemHolder.parent2.setTag(position);

  itemHolder.parent1.setOnClickListener(this);
  itemHolder.parent2.setOnClickListener(this);

  itemHolder.time.setText(clsOnlineReport.getBulletinTime());
  itemHolder.title.setText(clsOnlineReport.getBulletinTitle());
  itemHolder.author.setText(clsOnlineReport.getCreater());
 }

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

 @Override
 public boolean onItemMove(int fromPosition, int toPosition) {
  Collections.swap(mList, fromPosition, toPosition);
  notifyItemMoved(fromPosition, toPosition);
  return true;
 }

 class ItemHolder extends RecyclerView.ViewHolder {

  @BindView(R.id.online_report_time)
  TextView time;
  @BindView(R.id.online_report_title)
  TextView title;
  @BindView(R.id.online_report_author)
  TextView author;
  @BindView(R.id.online_report_drag)
  ImageView drag;
  @BindView(R.id.online_report_checkbox)
  ImageView checkbox;
  @BindView(R.id.view_parent_1)
  LinearLayout parent1;
  @BindView(R.id.view_parent_2)
  LinearLayout parent2;

  ItemHolder(View itemView) {
   super(itemView);
   ButterKnife.bind(this, itemView);
  }
 }

 @Override
 public void onClick(View v) {
  mCallback.onClick(v, (int) v.getTag());
 }

 public interface Callback {
  void onClick(View v, int position);
 }
}

/**
 * 用来完成RecyclerView长按拖拽的关键接口
 * 1.getMovementFlags里面表示设置为上下拖动
 * 2.onSelectedChanged里面表示拖动状态下改变背景色，拖动完成后恢复背景色
 * 3.拖动完成的时候viewHolder的值为空！！！所以要用srcHolder
 */
public class OnlineReportListCallback extends ItemTouchHelper.Callback {

 private ColorDrawable drawable;
 private RecyclerView.ViewHolder srcHolder;

 public interface ItemTouchMoveListener {
  boolean onItemMove(int fromPosition, int toPosition);
 }

 private ItemTouchMoveListener moveListener;

 public OnlineReportListCallback(ItemTouchMoveListener moveListener) {
  this.moveListener = moveListener;

  int rgb = Color.rgb(0xff, 0xff, 0xff);
  drawable = new ColorDrawable(rgb);
 }


 @Override
 public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {

  int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
  return makeMovementFlags(dragFlags, ItemTouchHelper.ACTION_STATE_IDLE);
 }

 @Override
 public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder srcHolder, RecyclerView.ViewHolder targetHolder) {

  this.srcHolder = srcHolder;
  return srcHolder.getItemViewType() == targetHolder.getItemViewType() && moveListener.onItemMove(srcHolder.getAdapterPosition(), targetHolder.getAdapterPosition());
 }

 @Override
 public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {

 }

 @Override
 public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {

  super.onSelectedChanged(viewHolder, actionState);

  if (actionState == ItemTouchHelper.ACTION_STATE_DRAG) {
   viewHolder.itemView.setBackground(null);
  }

  if (actionState == ItemTouchHelper.ACTION_STATE_IDLE) {
   srcHolder.itemView.setBackground(drawable);
  }
 }
}