RecyclerView 是否有等效的 addHeaderView?

编程入门行业动态更新时间:2024-10-07 04:24:07

本文介绍了RecyclerView 是否有等效的 addHeaderView?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！问题描述

我正在寻找与 addHeaderView 等效的回收器视图.基本上我想将带有 2 个按钮的图像作为标题添加到列表视图中.是否有不同的方法将标题视图添加到回收站视图?指导示例会有所帮助

I'm looking for an equivalent to addHeaderView for a recycler view. Basically I want to have an image with 2 buttons be added as a header to the listview. Is there a different way to add a header view to a recycler view? An example for guidance would be helpful

EDIT 2(添加片段布局):

EDIT 2 (added fragment layouts):

添加日志语句后，似乎 getViewType 只接收到 0 的位置.这导致 onCreateView 只加载一个布局:

After adding log statements, it seems as though getViewType only ever receives a position of 0. This leads to onCreateView only loading the one layout:

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:

The fragment transition to load the CommentFragment:

@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); fragmentTransactionmit(); } }

Fragment 的 onCreateView:

The Fragment's 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:

评论行布局:

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="schemas.android/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_margin="10dp" android:background="@color/white">  <ImageView android:layout_width="80dp" android:layout_height="80dp" android:id="@+id/profile_picture" android:background="@color/blue_testapp"/>  <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" />  <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

适配器代码(感谢 hister 让我入门):

The Adapter code (thanks to hister for getting me started):

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; thisments = 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)ment.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.idment); 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，只有头部布局显示为viewType始终为0.看起来像this.如果我强制使用其他布局，它看起来像 this:

Using the above code, only the header layout is displayed as viewType is always 0. It looks like this. If I force the other layout it looks like this:

推荐答案

没有像 listview.addHeaderView() 这样简单的方法，但您可以通过向适配器添加类型来实现这一点标题.

There isn't an easy way like listview.addHeaderView() but you can achieve this by adding a type to your adapter for header.

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); } } }