Android中怎么實現可拖拽列表和多選功能

Android中怎么實現可拖拽列表和多選功能，很多新手對此不是很清楚，為了幫助大家解決這個難題，下面小編將為大家詳細講解，有這方面需求的人可以來學習下，希望你能有所收獲。

主窗口JAVA代碼

/** * 編輯狀態下長按拖動條目 * 1.通過ItemTouchHelper.Callback實現長按拖動 * 2.通過isEditable的值判斷是否編輯狀態，初值是false * 3.切換編輯狀態要把isEditable的值取反，并改變復選框圖標狀態 * 4.在編輯狀態下，按返回鍵回到非編輯狀態 * 5.RecyclerView的點擊事件通過RecyclerAdapter.Callback實現 */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);  //初始狀態為非編輯模式  setIsEditable(false);  //初始化拖動接口  OnlineReportListCallback callback = new OnlineReportListCallback(mAdapter);  itemTouchHelper = new ItemTouchHelper(callback);  //初始狀態為不可拖動  setRecyclerViewDraggable(false); } //生成模擬數據 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);  //設置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);     //在編輯模式下，點擊條目切換顯示checkbox，并且判斷選中條目的數量，     if (getIsEditable()) {      if (clsOnlineReport.getIsCheckBoxVisible()) {       clsOnlineReport.setIsChecked(!clsOnlineReport.getIsChecked());       mAdapter.notifyDataSetChanged();      }      for (int i = 0; i < mClsOnlineReportList.size(); i++) {       //數量等于0，隱藏工具條，否則顯示工具條       ClsOnlineReport onlineReport = mClsOnlineReportList.get(i);       if (onlineReport.getIsChecked()) {        mToolbar.setVisibility(View.VISIBLE);        break;       }       if (i == mClsOnlineReportList.size() - 1) {        mToolbar.setVisibility(View.GONE);       }      }     } else {      //在非編輯模式下，點擊條目直接跳轉詳情頁，并把bulletinID傳過去      Intent intent = new Intent(mContext, ReportDetailActivity.class);      intent.putExtra("bulletinID", clsOnlineReport.getBulletinID());      startActivityForResult(intent, 16371);     }   }  }); } @Override public void onBackPressed() {  //編輯狀態下，按返回鍵回到非編輯狀態，否則退出  if (getIsEditable()) {   switchEditable();  } else {   finish();  } } @Override public void onClick(View v) {  //編輯狀態下，按返回鍵回到非編輯狀態，否則退出  if (v.getId() == R.id.title_left) {   if (getIsEditable()) {    switchEditable();   } else {    finish();   }  }  //點擊編輯按鈕切換編輯狀態  if (v.getId() == R.id.edit_tv) {   switchEditable();  }  //工具條的按鈕對應不同的接口  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, "在此處調用接口", Toast.LENGTH_SHORT).show();  } } private void switchEditable() {  //將屬性取反  setIsEditable(!getIsEditable());  //遍歷列表并賦值  for (ClsOnlineReport clsOnlineReport : mClsOnlineReportList) {   clsOnlineReport.setIsCheckBoxVisible(getIsEditable());   clsOnlineReport.setIsChecked(false);  }  //通知適配器刷新  mAdapter.notifyDataSetChanged();  //隱藏工具條  mToolbar.setVisibility(View.GONE);  //切換拖動狀態  setRecyclerViewDraggable(getIsEditable()); } public boolean getIsEditable() {  return isEditable; } public void setIsEditable(boolean isEditable) {  this.isEditable = isEditable; } //設置能否拖動 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) {  //當詳情頁的數據有變動則刷新列表  if (requestCode == 16371 && resultCode == RESULT_OK) {   refreshData();  }  super.onActivityResult(requestCode, resultCode, data); } private void refreshData() {  Toast.makeText(mContext, "在此處調用接口", Toast.LENGTH_SHORT).show(); }}

適配器代碼

/** * 可拖拽列表的適配器， * 1.需要實現OnlineReportListCallback.ItemTouchMoveListener * 2.持有一個接口用于傳遞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); }}

需要實現的接口

/** * 用來完成RecyclerView長按拖拽的關鍵接口 * 1.getMovementFlags里面表示設置為上下拖動 * 2.onSelectedChanged里面表示拖動狀態下改變背景色，拖動完成后恢復背景色 * 3.拖動完成的時候viewHolder的值為空！！！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);  } }}

圖片使用Android Studio內置的SVG，引入了ButterKnife綁定控件，另外內部類使用了lambda表達式折疊了，重點說一下RecyclerAdapter.Callback，這個接口的內部方法 void onClick(View v, int position) 是在View.OnClickListener的void onClick(View v)的基礎上多傳了一個參數，這個參數是放在tag里面的，其他難點注釋里面都有

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