拖放 RecyclerView - 限制对特定视图的触摸

Question

我正在尝试在 recyclerview 中实现拖放。我成功地实现了它。但我有一个小问题。只有当我拖动特定的 viewHolder（一个 ImageView）时才会发生拖放。但是在我的 recyclerview 中，当我触摸行的任何部分并拖动时，该项目开始拖动。我只希望在触摸 ImageView 并拖动时拖动行或项目。

我遵循了这个教程：https://medium.com/@ipaulpro/drag-and-swipe-with-recyclerview-b9456d2b1aaf

代码：

public class EditItemTouchHelperCallback extends ItemTouchHelper.Callback {

private final PlaylistUserAdapter mAdapter;


public EditItemTouchHelperCallback(PlaylistUserAdapter adapter) {
    mAdapter = adapter;

}

@Override
public boolean isLongPressDragEnabled() {
    return true;
}

@Override
public boolean isItemViewSwipeEnabled() {
    return true;
}



@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
    int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
    int swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END;
    return makeMovementFlags(dragFlags, swipeFlags);
}

@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder,
                      RecyclerView.ViewHolder target) {
    mAdapter.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());
    return true;
}

@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
    mAdapter.onItemDismiss(viewHolder.getAdapterPosition());
}

适配器：

public class PlaylistUserAdapter extends RecyclerView.Adapter<PlaylistUserAdapter.ViewHolder> implements ItemTouchHelperAdapter{

private Context context;
private ArrayList<SongInfoModel> SongList = new ArrayList<>();
private RecyclerItemClickListener listener;
private final OnStartDragListener mDragStartListener;
private SparseBooleanArray expandState = new SparseBooleanArray();

public PlaylistUserAdapter(Context context, ArrayList<SongInfoModel> songList,OnStartDragListener dragListner,RecyclerItemClickListener listener) {
    this.context = context;
    SongList = songList;
    this.listener = listener;
    mDragStartListener = dragListner;
}

@Override
public PlaylistUserAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(context).inflate(R.layout.row_song, parent, false);
    return new ViewHolder(view);
}

@Override
public void onBindViewHolder(final PlaylistUserAdapter.ViewHolder holder, int position) {

    final SongInfoModel songInfoModel = SongList.get(position);

    final boolean isExpanded = expandState.get(position);
    holder.expandableLayout.setVisibility(isExpanded?View.VISIBLE:View.GONE);
    holder.songName.setText(songInfoModel.SongName);
    holder.artistName.setText(songInfoModel.ArtistName);
    holder.duration.setText(String.valueOf(songInfoModel.duration));
    String duration = Utility.convertDuration(songInfoModel.getDuration());
    holder.duration.setText(duration);
    Picasso.with(context).load(songInfoModel.getAlbumIDArtwork()).placeholder(R.drawable.ic_launcher).into(holder.iv_artwork);
    Picasso.with(context).load(R.mipmap.drag).into(holder.expandArrow);
    holder.bind(songInfoModel, listener);

    holder.expandArrow.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View view, MotionEvent motionEvent) {

            if (MotionEventCompat.getActionMasked(motionEvent) == MotionEvent.ACTION_DOWN) {
                mDragStartListener.onStartDrag(holder,songInfoModel);}
            return false;

        }

    });



}



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



@Override
public boolean onItemMove(int fromPosition, int toPosition) {


    ContentResolver cr = context.getContentResolver();


    if (fromPosition < SongList.size() && toPosition < SongList.size()) {
        if (fromPosition < toPosition) {
            for (int i = fromPosition; i < toPosition; i++) {
                Collections.swap(SongList, i, i + 1);


            }
        } else {
            for (int i = fromPosition; i > toPosition; i--) {
                Collections.swap(SongList, i, i - 1);


            }
        }
        notifyItemMoved(fromPosition, toPosition);

    }

    PlayListUser.trackMoved(fromPosition,toPosition, cr, SongList);




    return true;


}

@Override
public void onItemDismiss(int position) {

    SongList.remove(position);
    notifyItemRemoved(position);

}





    public class ViewHolder extends RecyclerView.ViewHolder implements ItemTouchHelperViewHolder {

    private TextView songName;
    private TextView artistName;
    private TextView duration;
    private ImageView iv_artwork;
    private ImageView expandArrow;
    private RelativeLayout expandableLayout;
    private CardView card_view;
    private LinearLayout PlaySongLayout;
    private LinearLayout AddPlayListLayout;
    private LinearLayout EditTag;
    private LinearLayout RingtoneLayout;
    private LinearLayout ShareLayout;
    private LinearLayout DeleteLayout;

    public ViewHolder(View itemView) {
        super(itemView);
        songName = (TextView)itemView.findViewById(R.id.SongName);
        artistName= (TextView)itemView.findViewById(R.id.ArtistName);
        duration = (TextView) itemView.findViewById(R.id.duration);
        iv_artwork = (ImageView) itemView.findViewById(R.id.iv_artwork);
        expandableLayout =  itemView.findViewById(R.id.expandableLayout);
        card_view = itemView.findViewById(R.id.card_view);
        expandArrow=itemView.findViewById(R.id.expandArrow);
        PlaySongLayout = itemView.findViewById(R.id.PlaySongLayout);
        AddPlayListLayout = itemView.findViewById(R.id.AddPlayListLayout);
        EditTag = itemView.findViewById(R.id.EditTag);
        RingtoneLayout = itemView.findViewById(R.id.RingtoneLayout);
        ShareLayout = itemView.findViewById(R.id.ShareLayout);
        DeleteLayout = itemView.findViewById(R.id.DeleteLayout);
    }

    public void bind(final SongInfoModel songInfoModel, final RecyclerItemClickListener listener) {
        itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                listener.onClickListener(songInfoModel, getLayoutPosition());

            }
        });

        itemView.setOnLongClickListener(new View.OnLongClickListener() {

            @Override
            public boolean onLongClick(View view) {

                listener.onLongClickListener(songInfoModel, getLayoutPosition(),view);

                onClickButton(expandableLayout,getLayoutPosition(),card_view);


                return true;
            }
        });

    }

    @Override
    public void onItemSelected() {
        itemView.setBackgroundColor(Color.LTGRAY);
    }

    @Override
    public void onItemClear() {

        itemView.setBackgroundColor(0);
    }

Answer 1

如教程所说

创建 OnStartDragListener 接口

import android.support.v7.widget.RecyclerView;

public interface OnStartDragListener {
    void onStartDrag(RecyclerView.ViewHolder viewHolder);
}

并在您从片段/活动创建一个时将其传递给您的适配器

myAdapteradapter = new myAdapteradapter (new OnStartDragListener() {

                    @Override
                    public void onStartDrag(RecyclerView.ViewHolder viewHolder) {
                        mItemTouchHelper.startDrag(viewHolder);
                    }
                });

在 onBindViewHolder 方法中，你应该设置 OnTouchListener 来查看你想成为句柄（你的 ImageView）并在你的持有人上调用 onStartDrag() 方法

holder.imageReorder.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if (event.getActionMasked() == MotionEvent.ACTION_DOWN) {
                    mDragStartListener.onStartDrag(holder);
                    return true;
                }
                return false;
            }
        });