在RecyclerView上删除项目时没有动画

Question

我是RecyclerView第一次使用.一切都工作正常,除了项目删除没有动画,即使项目添加动画工作正常.

我没有设置任何自定义项动画师,但根据文档:

默认情况下,启用添加和删除项目的动画RecyclerView.

所以关于删除的动画应该有效.

我希望删除默认动画,但无法使其工作.

这就是我设置RecyclerView的方法:

private void setupRecyclerView() {
  mRecyclerView = (RecyclerView) mRootView.findViewById(R.id.recycler_view);
  mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
  View emptyView = mRootView.findViewById(R.id.empty_view);
  mAdapter = new RoutineAdapter(getActivity(), mRoutineItems, emptyView);
  mRecyclerView.setAdapter(mAdapter);
}

这是我的适配器:

private class RoutineAdapter
      extends RecyclerView.Adapter<RoutineAdapter.ViewHolder> {

private final Context mContext;
private List<RoutineItem> mData;
private View mEmptyView;

    public RoutineAdapter(Context context, List<RoutineItem> data, View emptyView) {
      mContext = context;
      mData = data;
      mEmptyView = emptyView;
      setEmptyViewVisibility();
    }

    public void add(RoutineItem routineItem, int position) {
      mData.add(position, routineItem);
      setEmptyViewVisibility();
      notifyItemInserted(position);
    }

    public void remove(int position){
      mData.remove(position);
      setEmptyViewVisibility();
      notifyItemRemoved(position);
    }

    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
      final View view = LayoutInflater.from(mContext).inflate(
          R.layout.fragment_routines_list_item, parent, false);
      return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, final int position) {
      final RoutineItem routineItem = getItem(position);
      holder.circle.setBackgroundResource(
          colorNumberToDrawableResource(routineItem.colorNumber));
      holder.initial.setText(routineItem.routineName.substring(0, 1));
      holder.routineName.setText(routineItem.routineName);
      holder.lastTimeDone.setText(routineItem.lastTimeDoneText);
      if (routineItem.isSelected) {
        holder.itemView.setBackgroundColor(
            getResources().getColor(R.color.background_item_selected));
      } else {
        holder.itemView.setBackgroundResource(
            R.drawable.darker_background_on_pressed);
      }
      holder.itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
          mPresenter.onRoutineClicked(routineItem.routineName);
        }
      });
      holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
        @Override
        public boolean onLongClick(View v) {
          mPresenter.onRoutineLongClicked(routineItem.routineName);
          return true;
        }
      });
    }

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

    public RoutineItem getItem(int position) {
      return mData.get(position);
    }

    private void setEmptyViewVisibility() {
      if (getItemCount() == 0) {
        mEmptyView.setVisibility(View.VISIBLE);
      } else {
        mEmptyView.setVisibility(View.GONE);
      }
    }

    class ViewHolder extends RecyclerView.ViewHolder {
      public final View circle;
      public final TextView initial;
      public final TextView routineName;
      public final TextView lastTimeDone;

      public ViewHolder(View view) {
        super(view);
        circle = view.findViewById(R.id.circle);
        initial = (TextView) view.findViewById(R.id.initial);
        routineName = (TextView) view.findViewById(R.id.routine_name);
        lastTimeDone = (TextView) view.findViewById(R.id.last_time_done);
      }
    }
}

Fragment_routines_list_item.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:minHeight="@dimen/standard_list_item_height"
  android:paddingBottom="8dp"
  android:background="@drawable/darker_background_on_pressed"
  android:clickable="true">
    ......
</RelativeLayout>

我做错了什么导致默认删除动画不起作用？

Answer 1

从回收站视图中删除项目的正确方法是从数据集中删除该项目,然后告诉适配器该项目已被删除

myDataset.remove(position); // myDataset is List<MyObject>
mAdapter.notifyItemRemoved(position);

Answer 2

解决了它.

问题是,在调用之后mAdapter.remove(position),我的代码的另一部分是调用mAdapter.notifyDataSetChanged(),我假设停止删除动画.

总而言之,如果您mAdapter.notifyDataSetChanged在正在进行动画时进行调用,则动画将停止.

Answer 3

使用notifyItemRemoved(position)而不是 notifyDataSetChanged()像下面那样

myDataset.remove(position);
notifyItemRemoved(position);

因为notifyDataSetChanged()只是在没有任何动画的情况下通知更新的数据.

Answer 4

我能够使用动画和更新的索引删除视图,如下所示:

在适配器内,

public boolean removeItem(int position) {
    if (data.size() >= position + 1) {
        data.remove(position);
        return true;
    }
    return false;
}

删除视图时,请致电

if (adapter.removeItem(position)) {
    adapter.notifyItemRemoved(position);
    adapter.notifyItemRangeChanged(position, adapter.getItemCount());
}

我使用了一个布尔方法来确保双击等.不要导致崩溃.

Answer 5

经过长时间的调试，我意识到我必须添加setHasStableIds(true)到我的适配器并实现

@Override
public long getItemId(int position) {
    return position;
}

在那之后删除动画开始工作

Answer 6

没有正确工作删除动画的另一个原因可能是RecyclerViews高度.验证高度match_parent和NOT wrap_content!