RecyclerView实现拖拽排序效果

ItemTouchHelper helper = new ItemTouchHelper(new ItemTouchHelper.Callback() { 
  @Override 
  public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) { 
   int dragFrlg = 0; 
   if (recyclerView.getLayoutManager() instanceof GridLayoutManager){ 
    dragFrlg = ItemTouchHelper.UP|ItemTouchHelper.DOWN|ItemTouchHelper.LEFT|ItemTouchHelper.RIGHT; 
   }else if(recyclerView.getLayoutManager() instanceof LinearLayoutManager){ 
    dragFrlg = ItemTouchHelper.UP|ItemTouchHelper.DOWN; 
   } 
   return makeMovementFlags(dragFrlg,0); 
  } 
 
  @Override 
  public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) { 
   //滑动事件 下面注释的代码，滑动后数据和条目错乱，被舍弃 
//   Collections.swap(datas,viewHolder.getAdapterPosition(),target.getAdapterPosition()); 
//   ap.notifyItemMoved(viewHolder.getAdapterPosition(),target.getAdapterPosition()); 
 
   //得到当拖拽的viewHolder的Position 
   int fromPosition = viewHolder.getAdapterPosition(); 
   //拿到当前拖拽到的item的viewHolder 
   int toPosition = target.getAdapterPosition(); 
   if (fromPosition  toPosition; i--) { 
     Collections.swap(datas, i, i - 1); 
    } 
   } 
   ap.notifyItemMoved(fromPosition, toPosition); 
   return true; 
  } 
 
  @Override 
  public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) { 
    //侧滑删除可以使用； 
  } 
 
  @Override 
  public boolean isLongPressDragEnabled() { 
   return true; 
  } 
  /** 
   * 长按选中Item的时候开始调用 
   * 长按高亮 
   * @param viewHolder 
   * @param actionState 
   */ 
  @Override 
  public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) { 
   if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) { 
    viewHolder.itemView.setBackgroundColor(Color.RED); 
    //获取系统震动服务//震动70毫秒 
    Vibrator vib = (Vibrator) getSystemService(Service.VIBRATOR_SERVICE); 
    vib.vibrate(70); 
   } 
   super.onSelectedChanged(viewHolder, actionState); 
  } 
 
  /** 
   * 手指松开的时候还原高亮 
   * @param recyclerView 
   * @param viewHolder 
   */ 
  @Override 
  public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) { 
   super.clearView(recyclerView, viewHolder); 
   viewHolder.itemView.setBackgroundColor(0); 
   ap.notifyDataSetChanged(); //完成拖动后刷新适配器，这样拖动后删除就不会错乱 
  } 
 }); 

helper.attachToRecyclerView(rv); 

public class MainActivity extends AppCompatActivity implements View.OnClickListener { 
 private final String TAG = this.getClass().getSimpleName(); 
 private List d = Arrays.asList( 
   "A","B","C","D","E","F","G" 
   ,"H","I","J","K","L","M","N" 
   ,"O","P","Q","R","S","T" 
   ,"U","V","W","X","Y","Z"); 
 private RecyclerView rv ; 
 private Ap ap; 
 private List datas; 
 private EditText edAdd; 
 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.activity_main); 
  initData(); 
  rv = findViewById(R.id.rv); 
  edAdd =findViewById(R.id.et_add); 
  rv.setLayoutManager(new GridLayoutManager(this,3)); 
//  rv.setLayoutManager(new LinearLayoutManager(this)); 
  ap = new Ap(this, datas); 
  rv.setAdapter(ap); 
  helper.attachToRecyclerView(rv); 
  findViewById(R.id.tv).setOnClickListener(this); 
  findViewById(R.id.tv_add).setOnClickListener(this); 
 } 
 
 private void initData() { 
  datas = new ArrayList<>(); 
//  直接用d操作集合会崩溃，Arrays.asList集合不可增删改；详细可以看我的博客 
  for (int i = 0; i  extends RecyclerView.Adapter{ 
  private Context context; 
  public List stringList; 
  public Ap(Context context, List stringList) { 
   this.cOntext= context; 
   this.stringList = stringList; 
  } 
 
  @Override 
  public Ap.Vh onCreateViewHolder(ViewGroup parent, int viewType) { 
   return new Vh(LayoutInflater.from(context).inflate(R.layout.item_rv,null)); 
  } 
 
  @Override 
  public void onBindViewHolder(Ap.Vh holder, final int position) { 
   holder.tv.setText(stringList.get(position).toString()); 
   holder.iv.setOnClickListener(new View.OnClickListener() { 
    @Override 
    public void onClick(View view) { 
     remove(position); 
    } 
   }); 
  } 
 
  @Override 
  public int getItemCount() { 
   return stringList.size(); 
  } 
 
  public void add(T item){ 
   int position = stringList.size(); 
   stringList.add(item); 
   notifyItemInserted(position); 
  } 
 
  public void add(int position,T item){ 
   stringList.add(position,item); 
   notifyItemInserted(position); 
  } 
//  public void remove(T item) { 
//   final int position = stringList.indexOf(item); 
//   if (-1 == position) 
//    return; 
//   stringList.remove(item); 
//   notifyItemRemoved(position); 
//  } 
 
  public void remove(int position) { 
   stringList.remove(position); 
   notifyItemRemoved(position); 
   notifyItemRangeChanged(position,stringList.size()); 
  } 
 
  class Vh extends RecyclerView.ViewHolder { 
 
   public Vh(View itemView) { 
    super(itemView); 
    tv = itemView.findViewById(R.id.tv); 
    iv = itemView.findViewById(R.id.iv_delete); 
   } 
   public TextView tv; 
   public ImageView iv; 
  } 
 } 

 ItemTouchHelper helper = new ItemTouchHelper(new ItemTouchHelper.Callback() { 
  @Override 
  public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) { 
   int dragFrlg = 0; 
   if (recyclerView.getLayoutManager() instanceof GridLayoutManager){ 
    dragFrlg = ItemTouchHelper.UP|ItemTouchHelper.DOWN|ItemTouchHelper.LEFT|ItemTouchHelper.RIGHT; 
   }else if(recyclerView.getLayoutManager() instanceof LinearLayoutManager){ 
    dragFrlg = ItemTouchHelper.UP|ItemTouchHelper.DOWN; 
   } 
   return makeMovementFlags(dragFrlg,0); 
  } 
 
  @Override 
  public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) { 
   //滑动事件 下面注释的代码，滑动后数据和条目错乱，被舍弃 
//   Collections.swap(datas,viewHolder.getAdapterPosition(),target.getAdapterPosition()); 
//   ap.notifyItemMoved(viewHolder.getAdapterPosition(),target.getAdapterPosition()); 
 
   //得到当拖拽的viewHolder的Position 
   int fromPosition = viewHolder.getAdapterPosition(); 
   //拿到当前拖拽到的item的viewHolder 
   int toPosition = target.getAdapterPosition(); 
   if (fromPosition  toPosition; i--) { 
     Collections.swap(datas, i, i - 1); 
    } 
   } 
   ap.notifyItemMoved(fromPosition, toPosition); 
   return true; 
  } 
 
  @Override 
  public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) { 
    //侧滑删除可以使用； 
  } 
 
  @Override 
  public boolean isLongPressDragEnabled() { 
   return true; 
  } 
  /** 
   * 长按选中Item的时候开始调用 
   * 长按高亮 
   * @param viewHolder 
   * @param actionState 
   */ 
  @Override 
  public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) { 
   if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) { 
    viewHolder.itemView.setBackgroundColor(Color.RED); 
    //获取系统震动服务//震动70毫秒 
    Vibrator vib = (Vibrator) getSystemService(Service.VIBRATOR_SERVICE); 
    vib.vibrate(70); 
   } 
   super.onSelectedChanged(viewHolder, actionState); 
  } 
 
  /** 
   * 手指松开的时候还原高亮 
   * @param recyclerView 
   * @param viewHolder 
   */ 
  @Override 
  public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) { 
   super.clearView(recyclerView, viewHolder); 
   viewHolder.itemView.setBackgroundColor(0); 
   ap.notifyDataSetChanged(); //完成拖动后刷新适配器，这样拖动后删除就不会错乱 
  } 
 }); 
} 

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