如何使用动画删除 RecyclerView 适配器中的所有项目

Question

如果用户滑动，我想删除一个项目，如果用户单击 deleteAll 按钮，我想删除 RecyclerView 中的所有项目，我尝试访问每个视图并添加一个动画，但我现在不知道如何，我在创建中添加动画因为适配器给了我onBindViewHolder 中的每个视图持有者，这是我的适配器

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
Context context;
List<String> stringList;
public MyAdapter(Context context, List<String> stringList) {
    this.context = context;
    this.stringList = stringList;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(context)
            .inflate(R.layout.item,parent,false);

    MyViewHolder viewHolder = new MyViewHolder(view);
    return viewHolder;
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
    Animation animation = AnimationUtils.loadAnimation(context, android.R.anim.slide_in_left);
    holder.itemView.startAnimation(animation);
    holder.bind(stringList.get(position));
}


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



public void dismiss(int adapterPosition) {
            stringList.remove(adapterPosition);
            this.notifyItemRemoved(adapterPosition);
    }

public void removeItem(int position) {
    this.stringList.remove(position);
    notifyItemRemoved(position);
    notifyItemRangeChanged(position, getItemCount() - position);
}




class MyViewHolder extends RecyclerView.ViewHolder
        implements View.OnClickListener {
    TextView textView;
    String data;
    public MyViewHolder(View itemView) {
        super(itemView);
        textView = itemView.findViewById(R.id.text);
        itemView.setOnClickListener(this);
    }
    public void bind(String data) {
        this.data = data;
        textView.setText(data);
    }

    @Override
    public void onClick(View view) {
        stringList.remove(data);
        notifyDataSetChanged();
    }

}}

我的RecyclerView 和主要活动中的适配器以及我如何处理全部删除，但问题是我如何添加动画

  adapter = new MyAdapter(this,myList);
    ItemTouchHelper.Callback callback = new SwipeHelper(adapter);
    ItemTouchHelper helper = new ItemTouchHelper(callback);
    recyclerView.setAdapter(adapter);
    helper.attachToRecyclerView(recyclerView);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            for (int i = myList.size()-1 ; i >= 0 ; i--){
                adapter.removeItem(i);
            }
            //recyclerView.removeItemDecoration();
        }
    });

Answer 1

我通过在该项目上模拟滑动动画来一次删除一个项目，并在删除下一个项目之前发布延迟，依此类推直到RecyclerView的最后一个项目

第一步：

在您的包含全部清除按钮和RecyclerView 实例的活动中：创建单项删除方法

private void deleteItem(View rowView, final int position) {

    Animation anim = AnimationUtils.loadAnimation(requireContext(),
            android.R.anim.slide_out_right);
    anim.setDuration(300);
    rowView.startAnimation(anim);

    new Handler().postDelayed(new Runnable() {
        public void run() {
            if (myDataSource.size() == 0) {
                addEmptyView(); // adding empty view instead of the RecyclerView
                return;
            }
            myDataSource.remove(position); //Remove the current content from the array
            myRVAdapter.notifyDataSetChanged(); //Refresh list
        }

    }, anim.getDuration());
}

第 2 步：

创建将删除所有RecyclerView 列表项的方法>> 在您的按钮单击回调中调用它。

boolean mStopHandler = false;

private void deleteAllItems() {

    final Handler handler = new Handler();
    Runnable runnable = new Runnable() {
        @Override
        public void run() {
            
            if (myDataSource.size() == 0) {
                mStopHandler = true;
            }
            
            if (!mStopHandler) {
                View v = myRecyclerView.findViewHolderForAdapterPosition(0).itemView;
                deleteItem(v, 0);
            } else {
                handler.removeCallbacksAndMessages(null);
            }
            
            handler.postDelayed(this, 250);
        }
    };
    requireActivity().runOnUiThread(runnable);
}

同样重要的是要处理清单、活动部分中的配置更改，就像在清除回收站视图列表时配置更改一样，会引发异常

<activity
    android:name=".activities.MainActivity"
    android:configChanges="orientation|screenSize|keyboard"
    android:label="@string/app_name"
    ...
</activity>

Answer 2

使用RecyclerView.ItemAnimator。

https://developer.android.com/reference/android/support/v7/widget/RecyclerView.ItemAnimator.html

该类将在项目上发生的动画定义为更改 被制成适配器。 ItemAnimator 的子类可用于 为 ViewHolder 项上的操作实现自定义动画。

您可以参考任何有关编写自定义ItemAnimator的教程：1，2

Answer 3

您可以在每个循环中使用线程和延迟来逐一删除/恢复项目。以下是我的实现方式：

MainActivity.java

clearItemsView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            final List<LineItem> lineItemsCopy = new ArrayList<>(lineItems);
            new Thread(new Runnable() {
                @Override
                public void run() {
                    for (int i=0; i<lineItemsCopy.size(); i++) {
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                salesOrderItemListAdapter.removeItem(0);
                            }
                        });
                        try {
                            Thread.sleep(500);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }).start();
            Snackbar snackbar = Snackbar.make(coordinatorLayout, getString(R.string.items_cleared_message), Snackbar.LENGTH_LONG)
                    .setAction(getString(R.string.label_undo), new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            new Thread(new Runnable() {
                                @Override
                                public void run() {
                                    for (int i=0; i<lineItemsCopy.size(); i++) {
                                        final int finalI = i;
                                        runOnUiThread(new Runnable() {
                                            @Override
                                            public void run() {
                                                salesOrderItemListAdapter.restoreItem(lineItemsCopy.get(finalI), 0);
                                            }
                                        });
                                        try {
                                            Thread.sleep(500);
                                        } catch (InterruptedException e) {
                                            e.printStackTrace();
                                        }
                                    }
                                }
                            }).start();
                        }
                    }).setActionTextColor(Color.YELLOW);
            snackbar.show();
        }
    });

RecyclerViewAdapter.java

    //Only remove & restore functions are shown    
    public void removeItem(int position) {
        lineItems.remove(position);
        notifyItemRemoved(position);
    }

    public void restoreItem(LineItem item, int position) {
        lineItems.add(position, item);
        notifyItemInserted(position);
    }