android - 具有多 View 类型的 ItemTouchHelper

Question

public class ItemCallBack extends ItemTouchHelper.Callback {
private BaseDragAdapter adapter;
private List list;

public ItemCallBack(BaseDragAdapter adapter, List list) {
    this.adapter = adapter;
    this.list = list;
}

@Override
public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
    int dragFlags = 0; 
    int swipeFlags = 0;  
    int startPosition = viewHolder.getAdapterPosition();
    if (startPosition != 0) {
        if (recyclerView.getLayoutManager() instanceof GridLayoutManager) {
            dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
        } else if (recyclerView.getLayoutManager() instanceof LinearLayoutManager) {
            dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
        } else if (recyclerView.getLayoutManager() instanceof StaggeredGridLayoutManager) {
            dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
        }
    }
    return makeMovementFlags(dragFlags, swipeFlags);
}

@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) { 
    int startPosition = viewHolder.getAdapterPosition();
    int targetPosition = target.getAdapterPosition();
    adapter.onMoved(startPosition, targetPosition);
    return true;
}

@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {  //左右拖动删除
    int position = viewHolder.getAdapterPosition();
    adapter.onSwiped(position);
}

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

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


@Override
public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
    if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
        viewHolder.itemView.setScaleX(1.2f);
        viewHolder.itemView.setScaleY(1.2f);
    }
    super.onSelectedChanged(viewHolder, actionState);
}

@Override
public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
    super.clearView(recyclerView, viewHolder);
    viewHolder.itemView.setScaleX(1.0f);
    viewHolder.itemView.setScaleY(1.0f);
    onOrderListener.order();
}


@Override
public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
    super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
}

private OnOrderListener onOrderListener;

public void setOnPictureClickListener(OnOrderListener onOrderListener) {
    if (onOrderListener != null) {
        this.onOrderListener = onOrderListener;
    }
}

public interface OnOrderListener {
    void order();
}

}

@Override
public int getItemViewType(int position) {
    if (position == 0) {
        return TYPE_ADD;
    } else if (position == 1) {
        return TYPE_COVER;
    }
    return TYPE_NORMAL;
}

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    if (viewType == TYPE_ADD) {
        View view = LayoutInflater.from(context).inflate(R.layout.item_upload_pic_add, null);
        return new AddHolder(view);
    } else if (viewType == TYPE_COVER) {
        View view = LayoutInflater.from(context).inflate(R.layout.item_upload_pic_cover, null);
        return new CoverHolder(view);
    }  else {
        View view = LayoutInflater.from(context).inflate(R.layout.item_upload_pic_normal, null);
        return new NormalHolder(view);
    }
}

我想与 ItemTouchHelper 交换项目。

问题是:

When i drag and swap item that viewtype is TYPE_NORNAL,animation work well;
But When i try to switch between different types(ex:TYPE_NORMAL and TYPE_COVER),animation does not execute correctly.

如何让动画正确执行？

Answer 1

我也遇到了同样的问题。通过设置解决了它

setHasStableIds(true);

在适配器上，并重写 getItemId() ，以便它为适配器中的每个项目返回唯一的 id。如果您没有项目的唯一 id，则可以在获得适配器的新项目时生成 Map 并生成这些 id。然后使用 item 作为键在 getItemId() 中查找这些 id。