是否有任何简单的实现或教程可以在 android 中实现回收器视图



我正在尝试将我现有的项目移植到材料设计中,但无法理解RecyclerView的实现。我的旧代码使用列表视图,但我想要像列表一样的 GMail 应用程序。

我已经阅读了大量的教程,但其中大多数要么跳过ItemDecoration部分,要么跳过ClickListener部分。 不同的教程具有完全不同的实现,代码各不相同,以至于我无法理解在哪里放置什么。

我在下面苦苦挣扎,我通过阅读各种教程编译:

    适配器:
  1. 我的适配器代码如下:

    public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {
    private final Context mContext;
    private List<String> mData1, mData2;
    public MyAdapter(Context mContext, String[] data1,String[] data2) {
    this.mContext = mContext;
    if (data1 != null)
        mData1 = new ArrayList<String>(Arrays.asList(data1));
    else mData1 = new ArrayList<String>();
    if (data2 != null)
        mData2 = new ArrayList<String>(Arrays.asList(data2));
    else mData2 = new ArrayList<String>();
    }
    public void add(String s,int position) {
    position = position == -1 ? getItemCount()  : position;
    mData1.add(position,s);
    notifyItemInserted(position);
    }
    public void remove(int position){
    if (position < getItemCount()  ) {
        mData1.remove(position);
        notifyItemRemoved(position);
    }
    }
    
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
    LayoutInflater inflater = LayoutInflater.from(viewGroup.getContext());
    View itemView = inflater.inflate(R.layout.list_item,viewGroup,false);
    return new MyViewHolder(itemView);
    }
    @Override
    public void onBindViewHolder(MyViewHolder myViewHolder, int position) {
    myViewHolder.tv1.setText(mData1.get(position));
    myViewHolder.tv2.setText(mData2.get(position));
    myViewHolder.setClickListener(new MyViewHolder.ClickListener()
    {
         @Override
         public void onClick(View v, int pos) {
             Toast.makeText(mContext,"The selected position is: "+ pos,Toast.LENGTH_SHORT).show();
         }
      });
    
    
      }
      @Override
      public int getItemCount() {
      return mData1.size();
      }
      public static class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener
    {
    protected TextView tv1;
    protected TextView tv2;
    ClickListener clickListener;
    
    public MyViewHolder(View itemView) {
        super(itemView);
        tv1 = (TextView) itemView.findViewById(R.id.txt1);
        tv2 = (TextView) itemView.findViewById(R.id.txt2);
    
    }
    @Override
    public void onClick(View v) {
    }
    public void onClick(View v, int pos)
    {
        clickListener.onClick(v,getPosition());
    }
    public void setClickListener(ClickListener clickListener)
    {
        this.clickListener = clickListener;
    }
    
    public interface ClickListener
    {
        public void onClick(View v,int pos);
    }
    }
    }
    
  2. ItemDecoration从这里复制:https://gist.github.com/alexfu/0f464fc3742f134ccd1e。但是我真的需要这么大的类来在列表项之间放置简单的分隔符吗?如果我想自己实现代码怎么办?

  3. 我仍然无法弄清楚OnClickListener.首先,我想要一个简单的OnClickListener就像ListView.OnClickListener一样。当前OnClickListener是从教程编译的,但不起作用。

完整代码在这里:https://github.com/pauldmps/MaterialDesign/

回收器查看适配器示例:

  1. 适配器问题可以使用以下代码解决:

    public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder>         
    {
    private final Context mContext;
    private List<String> mData1, mData2;
    public MyAdapter(Context mContext, String[] data1, String[] data2) {
    this.mContext = mContext;
    if (data1 != null)
        mData1 = new ArrayList<String>(Arrays.asList(data1));
    else
        mData1 = new ArrayList<String>();
    if (data2 != null)
        mData2 = new ArrayList<String>(Arrays.asList(data2));
    else
        mData2 = new ArrayList<String>();
    }
    public void add(String s, int position) {
    position = position == -1 ? getItemCount() : position;
    mData1.add(position, s);
    notifyItemInserted(position);
    }
    public void remove(int position) {
    if (position < getItemCount()) {
        mData1.remove(position);
        notifyItemRemoved(position);
    }
    }
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
    LayoutInflater inflater = LayoutInflater.from(viewGroup.getContext());
    View itemView = inflater.inflate(R.layout.list_item, viewGroup, false);
    return new MyViewHolder(itemView);
    }
    @Override
    public void onBindViewHolder(MyViewHolder myViewHolder, final int position) {
        myViewHolder.tv1.setText(mData1.get(position));
    myViewHolder.tv2.setText(mData2.get(position));
    myViewHolder.itemView.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            clickListener.onClick(v, position);
        }
    });
    }
    @Override
    public int getItemCount() {
    return mData1.size();
    }
    ClickListener clickListener;
    public void setClickListener(ClickListener clickListener) {
    this.clickListener = clickListener;
    }
    public interface ClickListener {
    public void onClick(View v, int pos);
    }
    public static class MyViewHolder extends RecyclerView.ViewHolder {
    protected TextView tv1;
    protected TextView tv2;
    public MyViewHolder(View itemView) {
        super(itemView);
        tv1 = (TextView) itemView.findViewById(R.id.txt1);
        tv2 = (TextView) itemView.findViewById(R.id.txt2);
    }
    }
    }
    

用法如下:

MyAdapter adapter=....;
adapter.setClickListener(new ClickListener() {
        @Override
        public void onClick(View v, int pos) {
            // do whatever you want
        }
    });
  1. 没有任何简单的方法可以做到这一点。但我建议您一种解决方法。将下面的视图添加为list_item.xml底部的分隔线。

     <View
    android:layout_width="wrap_content"
    android:layout_height="0.5dip" 
    android:background="@color/light_gray"/>
    
  2. 项目单击侦听器也在上面的第 1 点中得到解决。

我希望这对你有所帮助。

下面是使用简单库实现回收器视图的示例

build.gradle中添加此行

implementation 'com.hereshem.lib:awesomelib:2.0.1'

在活动中创建回收器视图布局

<com.hereshem.lib.recycler.MyRecyclerView
        android:id="@+id/recycler"
        app:layoutManager="LinearLayoutManager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

通过传递视图持有人支持的类来创建视图持有人

public static class EVHolder extends MyViewHolder<Events> {
    TextView date, title, summary;
    public EVHolder(View v) {
        super(v);
        date = v.findViewById(R.id.date);
        title = v.findViewById(R.id.title);
        summary = v.findViewById(R.id.summary);
    }
    @Override
    public void bindView(Events c) {
        date.setText(c.date);
        title.setText(c.title);
        summary.setText(c.summary);
    }
}

创建行很少的项列表变量和适配器

List<Events> items = new ArrayList<>();
MyRecyclerView recycler = findViewById(R.id.recycler);
RecyclerViewAdapter adapter = new RecyclerViewAdapter(this, items, EVHolder.class, R.layout.row_event);
recycler.setAdapter(adapter);

点击监听器可以添加以下行

recycler.setOnItemClickListener(new MyRecyclerView.OnItemClickListener() {
    @Override
    public void onItemClick(int position) {
        Toast.makeText(MainActivity.this, "Recycler Item Clicked " + position, Toast.LENGTH_SHORT).show();
    }
});

更多示例可以在这里找到

希望这对:)有所帮助

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