是否有与 RecyclerView 等效的 addHeaderView?

新手上路,请多包涵

我正在寻找与 addHeaderView 等效的回收站视图。基本上我希望将带有 2 个按钮的图像作为标题添加到列表视图。是否有不同的方法可以将标题视图添加到回收站视图?一个指导的例子会很有帮助

编辑 2(添加片段布局):

添加日志语句后,似乎 getViewType 只收到位置 0。这导致 onCreateView 只加载一个布局:

 10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemCount: 5
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemViewType position: 0
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemViewType position: 0
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> getItemViewType position: 0
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> onCreateViewHolder, viewtype: 0
10-26 16:32:53.766    5449-5449/co.testapp I/logger info﹕ Adapter-> onBindViewHolder, viewType: 0

加载 CommentFragment 的片段转换:

 @Override
public void onPhotoFeedItemClick(View view, int position) {
    if (fragmentManager == null)
        fragmentManager = getSupportFragmentManager();

FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

    if (view.getId() == R.id.button_comment){
        CommentFragment commentFragment = CommentFragment.newInstance("","", position);
        fragmentTransaction.add(R.id.main_activity, commentFragment,"comment_fragment_tag");
        fragmentTransaction.addToBackStack(Constants.TAG_COMMENTS);
        fragmentTransaction.commit();
    }
}

片段的 onCreateView:

 @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    View view = inflater.inflate(R.layout.fragment_comment, container, false);
    mRecyclerView = (RecyclerView) view.findViewById(R.id.list_recylclerview);
    mRecyclerView.setLayoutManager(new LinearLayoutManager(_context));
    mRecyclerView.setItemAnimator(new DefaultItemAnimator());
    mAdapter = new CommentAdapter(R.layout.row_list_comments, R.layout.row_header_comments, _context, comments);
    mRecyclerView.setAdapter(mAdapter);
    return view;
}

包含回收视图的片段:

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    tools:context="co.testapp.fragments.CommentFragment"
    android:background="@color/white">
        <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:orientation="vertical">
            <android.support.v7.widget.RecyclerView
                xmlns:android="http://schemas.android.com/apk/res/android"
                android:id="@+id/list_recylclerview"
                android:layout_width="match_parent"
                android:layout_height="200dp" />
        </RelativeLayout>
</RelativeLayout>

评论行布局:

 <?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent" android:layout_margin="10dp"
    android:background="@color/white">
    <!--Profile Picture-->
    <ImageView
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:id="@+id/profile_picture"
        android:background="@color/blue_testapp"/>
    <!--Name-->
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:text="First Name Last Name"
        android:textSize="16dp"
        android:textColor="@color/blue_testapp"
        android:id="@+id/name_of_poster"
        android:layout_toRightOf="@id/profile_picture"
        />
    <!--Comment-->
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:layout_marginTop="-5dp"
        android:text="This is a test comment"
        android:textSize="14dp"
        android:textColor="@color/black"
        android:id="@+id/comment"
        android:layout_below="@id/name_of_poster"
        android:layout_toRightOf="@id/profile_picture"/>
</RelativeLayout>

标题

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="300dp"
        android:id="@+id/header_photo"
        android:layout_gravity="center_horizontal"/>
</LinearLayout>

适配器代码(感谢 hister 让我开始):

 public class CommentAdapter extends RecyclerView.Adapter<ViewHolder>{

    private final int rowCardLayout;
    public static Context mContext;
    private final int headerLayout;
    private final String [] comments;
    private static final int HEADER = 0;
    private static final int OTHER = 1;

    public CommentAdapter(int rowCardLayout, int headerLayout, Context context, String [] comments) {
        this.rowCardLayout = rowCardLayout;
        this.mContext = context;
        this.comments = comments;
        this.headerLayout = headerLayout;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        logger.i("onCreateViewHolder, viewtype: " + i); //viewtype always returns 0 so OTHER layout is never inflated
        if (i == HEADER) {
            View v = LayoutInflater.from(viewGroup.getContext()).inflate(headerLayout, viewGroup, false);
            return new ViewHolderHeader(v);
        }
        else if (i == OTHER){
            View v = LayoutInflater.from(viewGroup.getContext()).inflate(rowCardLayout, viewGroup, false);
            return new ViewHolderComments(v);
        }
        else
          throw new RuntimeException("Could not inflate layout");
    }

    @Override
    public void onBindViewHolder(ViewHolder viewHolder, int i) {
        logger.i("onBindViewHolder, viewType: " + i);

        if (viewHolder instanceof ViewHolderComments)
            ((ViewHolderComments) viewHolder).comment.setText(comments[i].toString());
        if (viewHolder instanceof ViewHolderHeader)
           ((ViewHolderHeader) viewHolder).header.setImageResource(R.drawable.image2);
        else {
            logger.e("no instance of viewholder found");
        }
    }

    @Override
    public int getItemCount() {
        int count = comments.length + 1;
        logger.i("getItemCount: " + count);
        return count;
    }

    @Override
    public int getItemViewType(int position) {
        logger.i("getItemViewType position: " + position);
        if (position == HEADER)
            return HEADER;
        else
            return OTHER;
    }

    public static class ViewHolderComments extends RecyclerView.ViewHolder {
        public TextView comment;
        public ImageView image;

        public ViewHolderComments(View itemView) {
            super(itemView);
            comment = (TextView) itemView.findViewById(R.id.comment);
            image = (ImageView) itemView.findViewById(R.id.image);
        }
    }

    public static class ViewHolderHeader extends RecyclerView.ViewHolder {
        public final ImageView header;

        public ViewHolderHeader(View itemView){
            super(itemView);
            header = (ImageView) itemView.findViewById(R.id.header_photo);
        }
    }
}

使用上面的代码,只显示标题布局,因为 viewType 始终为 0。看起来像 这样。如果我强制使用其他布局,它看起来像 这样

原文由 ViciDroid 发布,翻译遵循 CC BY-SA 4.0 许可协议

阅读 445
2 个回答

没有像 listview.addHeaderView() 这样的简单方法,但您可以通过向适配器添加类型来实现此目的。

这是一个例子

public class HeaderAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
    private static final int TYPE_HEADER = 0;
    private static final int TYPE_ITEM = 1;
    String[] data;

    public HeaderAdapter(String[] data) {
        this.data = data;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if (viewType == TYPE_ITEM) {
            //inflate your layout and pass it to view holder
            return new VHItem(null);
        } else if (viewType == TYPE_HEADER) {
            //inflate your layout and pass it to view holder
            return new VHHeader(null);
        }

        throw new RuntimeException("there is no type that matches the type " + viewType + " + make sure your using types correctly");
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        if (holder instanceof VHItem) {
            String dataItem = getItem(position);
            //cast holder to VHItem and set data
        } else if (holder instanceof VHHeader) {
            //cast holder to VHHeader and set data for header.
        }
    }

    @Override
    public int getItemCount() {
        return data.length + 1;
    }

    @Override
    public int getItemViewType(int position) {
        if (isPositionHeader(position))
            return TYPE_HEADER;

        return TYPE_ITEM;
    }

    private boolean isPositionHeader(int position) {
        return position == 0;
    }

    private String getItem(int position) {
        return data[position - 1];
    }

    class VHItem extends RecyclerView.ViewHolder {
        TextView title;

        public VHItem(View itemView) {
            super(itemView);
        }
    }

    class VHHeader extends RecyclerView.ViewHolder {
        Button button;

        public VHHeader(View itemView) {
            super(itemView);
        }
    }
}

链接到 gist -> 这里

原文由 EC84B4 发布,翻译遵循 CC BY-SA 3.0 许可协议

这是我的解决方案,它使用一个抽象类来扩展你的适配器

abstract class HeaderAdapter<T : RecyclerView.ViewHolder>(headerView: View)
    : RecyclerView.Adapter<RecyclerView.ViewHolder>() {

    var headerView: View = headerView
        set(value) {
            notifyItemChanged(HEADER_POSITION)
            field = value
        }

    companion object {
        const val TYPE_HEADER = -1
        const val HEADER_POSITION = 0
    }

    abstract val itemCountWithoutHeader: Int
    abstract fun getViewHolder(parent: ViewGroup, viewType: Int): T
    abstract fun onBindItemViewHolder(holder: T, position: Int)

    open fun getItemsItemViewType(position: Int): Int {
        return super.getItemViewType(position)
    }

    final override fun getItemCount(): Int = itemCountWithoutHeader + 1

    final override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        return if (viewType == TYPE_HEADER) HeaderHolder(headerView) else getViewHolder(parent, viewType)
    }

    final override fun getItemViewType(position: Int): Int {
        return if (position == HEADER_POSITION) TYPE_HEADER else getItemsItemViewType(position)
    }

    final override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        if (position != HEADER_POSITION) onBindItemViewHolder(holder as T, position-1)
    }

    class HeaderHolder(itemView: View) : RecyclerView.ViewHolder(itemView)
}

原文由 Крест Доминика Туретта 发布,翻译遵循 CC BY-SA 4.0 许可协议

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