如何更新 RecyclerView 适配器数据 [英] How to update RecyclerView Adapter Data

问题描述

我想弄清楚更新 RecyclerView 的适配器有什么问题.

在获得新的产品列表后，我尝试:

1. 从创建recyclerView的片段更新ArrayList，设置新数据到adapter，然后调用adapter.notifyDataSetChanged()代码>;它没有用.

2. 像其他人一样创建一个新的适配器，它对他们有用，但对我来说没有任何变化:recyclerView.setAdapter(new RecyclerViewAdapter(newArrayList))>

3. 在Adapter中创建一个方法，更新数据如下:

    public void updateData(ArrayList viewModels) {items.clear();items.addAll(viewModels);notifyDataSetChanged();}

   然后每当我想更新数据列表时我都会调用这个方法；它没有用.

4. 为了检查我是否可以以任何方式修改 recyclerView，我尝试删除至少一个项目:

    public void removeItem(int position) {items.remove(位置);notifyItemRemoved(位置)；}

一切照旧.

这是我的适配器:

public class RecyclerViewAdapter extends RecyclerView.Adapter实现 View.OnClickListener {私有 ArrayList项目;私有 OnItemClickListener onItemClickListener;公共 RecyclerViewAdapter(ArrayList 项){this.items = 物品；}public void setOnItemClickListener(OnItemClickListener onItemClickListener) {this.onItemClickListener = onItemClickListener;}@覆盖公共 ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {查看 v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_recycler, parent, false);v.setOnClickListener(this);返回新的 ViewHolder(v);}public void updateData(ArrayListviewModels){items.clear();items.addAll(viewModels);notifyDataSetChanged();}public void addItem(int position, ViewModel viewModel) {items.add(position, viewModel);通知项目插入(位置)；}public void removeItem(int position) {items.remove(位置);notifyItemRemoved(位置)；}@覆盖公共无效 onBindViewHolder(ViewHolder 持有人，int 位置){ViewModel item = items.get(position);holder.title.setText(item.getTitle());Picasso.with(holder.image.getContext()).load(item.getImage()).into(holder.image);holder.price.setText(item.getPrice());holder.credit.setText(item.getCredit());holder.description.setText(item.getDescription());holder.itemView.setTag(item);}@覆盖公共 int getItemCount() {返回 items.size();}@覆盖public void onClick(final View v) {//给涟漪一些时间来完成效果如果(onItemClickListener ！= null){new Handler().postDelayed(new Runnable() {@覆盖公共无效运行(){onItemClickListener.onItemClick(v, (ViewModel) v.getTag());}}, 0);}}受保护的静态类 ViewHolder 扩展 RecyclerView.ViewHolder {公共 ImageView 图像；公共 TextView 价格、信用、标题、描述；公共 ViewHolder(查看 itemView){超级(项目视图)；image = (ImageView) itemView.findViewById(R.id.image);price = (TextView) itemView.findViewById(R.id.price);credit = (TextView) itemView.findViewById(R.id.credit);title = (TextView) itemView.findViewById(R.id.title);description = (TextView) itemView.findViewById(R.id.description);}}公共接口 OnItemClickListener {void onItemClick(View view, ViewModel viewModel);}}

然后我启动 RecyclerView 如下:

recyclerView = (RecyclerView) view.findViewById(R.id.recycler);recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 5));适配器 = 新 RecyclerViewAdapter(items);adapter.setOnItemClickListener(this);recyclerView.setAdapter(适配器)；

那么，我如何实际更新适配器数据以显示新收到的项目?

---

问题是 gridView 的布局如下:

<线性布局xmlns:android=http://schemas.android.com/apk/res/android"机器人:方向=垂直"android:layout_width=match_parent"android:tag="catalog_fragment";android:layout_height=match_parent"><框架布局机器人:方向=垂直"；android:layout_width=match_parent"android:layout_height=match_parent"><android.support.v7.widget.RecyclerViewandroid:id="@+id/recycler";android:layout_width=match_parent"android:layout_height=match_parent"android:clipToPadding="false"/><图像按钮android:id="@+id/fab";android:layout_gravity="顶部|结束";style=@style/FabStyle"/></FrameLayout></LinearLayout>

然后我删除了 LinearLayout 并将 FrameLayout 作为父布局.

解决方案

我正在使用 RecyclerView，移除和更新都运行良好.

1. 删除:

   从 RecyclerView 中删除项目有四个步骤

    list.remove(position);recycler.removeViewAt(position);mAdapter.notifyItemRemoved(position);mAdapter.notifyItemRangeChanged(position, list.size());

   这些代码行对我有用.

2. 更新数据:

   我唯一要做的就是:

    mAdapter.notifyDataSetChanged();

您必须在 Activity/Fragment 代码中完成所有这些操作，而不是在 RecyclerView Adapter 代码中.

I am trying to figure out what is the issue with updating RecyclerView's Adapter.

After I get a new List of products, I tried to:

1. Update the ArrayList from the fragment where recyclerView is created, set new data to adapter, and then call adapter.notifyDataSetChanged(); it did not work.

2. Create a new adapter, as others did, and it worked for them, but there wasn't any change for me: recyclerView.setAdapter(new RecyclerViewAdapter(newArrayList))

3. Create a method in Adapter which updates the data as follows:

    public void updateData(ArrayList<ViewModel> viewModels) {
       items.clear();
       items.addAll(viewModels);
       notifyDataSetChanged();
    }
   

   Then I call this method whenever I want to update the data list; it did not work.

4. To check if I can modify the recyclerView in any way, and I tried to remove at least an item:

     public void removeItem(int position) {
        items.remove(position);
        notifyItemRemoved(position);
    }
   

Everything remained as it was.

Here is my Adapter:

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> implements View.OnClickListener {

    private ArrayList<ViewModel> items;
    private OnItemClickListener onItemClickListener;

    public RecyclerViewAdapter(ArrayList<ViewModel> items) {
        this.items = items;
    }


    public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
        this.onItemClickListener = onItemClickListener;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_recycler, parent, false);
        v.setOnClickListener(this);
        return new ViewHolder(v);
    }

    public void updateData(ArrayList<ViewModel> viewModels) {
        items.clear();
        items.addAll(viewModels);
        notifyDataSetChanged();
    }
    public void addItem(int position, ViewModel viewModel) {
        items.add(position, viewModel);
        notifyItemInserted(position);
    }

    public void removeItem(int position) {
        items.remove(position);
        notifyItemRemoved(position);
    }


    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        ViewModel item = items.get(position);
        holder.title.setText(item.getTitle());
        Picasso.with(holder.image.getContext()).load(item.getImage()).into(holder.image);
        holder.price.setText(item.getPrice());
        holder.credit.setText(item.getCredit());
        holder.description.setText(item.getDescription());

        holder.itemView.setTag(item);
    }


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


    @Override
    public void onClick(final View v) {
        // Give some time to the ripple to finish the effect
        if (onItemClickListener != null) {
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    onItemClickListener.onItemClick(v, (ViewModel) v.getTag());
                }
            }, 0);
        }
    }

    protected static class ViewHolder extends RecyclerView.ViewHolder {
        public ImageView image;
        public TextView price, credit, title, description;

        public ViewHolder(View itemView) {
            super(itemView);
            image = (ImageView) itemView.findViewById(R.id.image);
            price = (TextView) itemView.findViewById(R.id.price);
            credit = (TextView) itemView.findViewById(R.id.credit);
            title = (TextView) itemView.findViewById(R.id.title);
            description = (TextView) itemView.findViewById(R.id.description);
        }
    }

    public interface OnItemClickListener {

        void onItemClick(View view, ViewModel viewModel);

    }
}

And I initiate RecyclerView as follows:

recyclerView = (RecyclerView) view.findViewById(R.id.recycler);
recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 5));
adapter = new RecyclerViewAdapter(items);
adapter.setOnItemClickListener(this);
recyclerView.setAdapter(adapter);

So, how do I actually update adapter data in order to display newly received items?

---

The issue was that the layout where gridView was looked as follows:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:tag="catalog_fragment"
    android:layout_height="match_parent">

    <FrameLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recycler"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:clipToPadding="false"/>

        <ImageButton
            android:id="@+id/fab"
            android:layout_gravity="top|end"
            style="@style/FabStyle"/>

    </FrameLayout>
</LinearLayout>

Then I just removed LinearLayout and made FrameLayout as the parent layout.

解决方案

I'm working with RecyclerView and both the remove and the update work well.

1. Remove:

   There are four steps to remove an item from a RecyclerView

    list.remove(position);
    recycler.removeViewAt(position);
    mAdapter.notifyItemRemoved(position);
    mAdapter.notifyItemRangeChanged(position, list.size());
   

   These lines of code work for me.

2. Update the data:

   The only things I had to do was:

    mAdapter.notifyDataSetChanged();
   

You had to do all of this in the Actvity/Fragment code, not in the RecyclerView Adapter code.

这篇关于如何更新 RecyclerView 适配器数据的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！