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问题:
I spent a moment trying to figure out a way to add a header to a RecyclerView, unsuccessfully. This is what I got so far:
@Override protected void onCreate(Bundle savedInstanceState) { ... layouManager = new LinearLayoutManager(getActivity()); recyclerView.setLayoutManager(layouManager); LayoutInflater inflater = (LayoutInflater) getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE); headerPlaceHolder = inflater.inflate(R.layout.view_header_holder_medium, null, false); layouManager.addView(headerPlaceHolder, 0); ... }
The LayoutManager seems to be the object handling the disposition of the RecyclerView items. As I couldn't find any addHeaderView(View view) method, I decided to go with the LayoutManager's addView(View view, int position) method and to add my header view in first position to act like a header.
Aaand this is where things get uglier:
java.lang.NullPointerException: Attempt to read from field 'android.support.v7.widget.RecyclerView$ViewHolder android.support.v7.widget.RecyclerView$LayoutParams.mViewHolder' on a null object reference at android.support.v7.widget.RecyclerView.getChildViewHolderInt(RecyclerView.java:2497) at android.support.v7.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:4807) at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:4803) at com.mathieumaree.showz.fragments.CategoryFragment.setRecyclerView(CategoryFragment.java:231) at com.mathieumaree.showz.fragments.CategoryFragment.access$200(CategoryFragment.java:47) at com.mathieumaree.showz.fragments.CategoryFragment$2.success(CategoryFragment.java:201) at com.mathieumaree.showz.fragments.CategoryFragment$2.success(CategoryFragment.java:196) at retrofit.CallbackRunnable$1.run(CallbackRunnable.java:41) at android.os.Handler.handleCallback(Handler.java:739) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5221) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
After getting several NullPointerExceptions trying to call the addView(View view) at different moments of the Activity creation (also tried adding the view once everything is set up, even the Adapter's data), I realized I have no idea if this is the right way to do it (and it doesn't look to be).
PS: Also, a solution that could handle the GridLayoutManager in addition to the LinearLayoutManager would be really appreciated!
回答1:
Found a very good article regarding this https://plus.google.com/+WillBlaschko/posts/3MFmgPbQuWx
I had to add a footer to my RecyclerView and here I'm sharing my code snippet as I thought it might be useful.
public class RecentCallsAdapter extends RecyclerView.Adapter { private static final int FOOTER_VIEW = 1; // Define a view holder for Footer view public class FooterViewHolder extends ViewHolder { public FooterViewHolder(View itemView) { super(itemView); itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // Do whatever you want on clicking the item } }); } } // Now define the viewholder for Normal list item public class NormalViewHolder extends ViewHolder { public NormalViewHolder(View itemView) { super(itemView); itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // Do whatever you want on clicking the normal items } }); } } // And now in onCreateViewHolder you have to pass the correct view // while populating the list item. @Override public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View v; if (viewType == FOOTER_VIEW) { v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_footer, parent, false); FooterViewHolder vh = new FooterViewHolder(v); return vh; } v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_normal, parent, false); NormalViewHolder vh = new NormalViewHolder(v); return vh; } // Now bind the viewholders in onBindViewHolder @Override public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { try { if (holder instanceof NormalViewHolder) { NormalViewHolder vh = (NormalViewHolder) holder; vh.bindView(position); } else if (holder instanceof FooterViewHolder) { FooterViewHolder vh = (FooterViewHolder) holder; } } catch (Exception e) { e.printStackTrace(); } } // Now the critical part. You have return the exact item count of your list // I've only one footer. So I returned data.size() + 1 // If you've multiple headers and footers, you've to return total count // like, headers.size() + data.size() + footers.size() @Override public int getItemCount() { if (data == null) { return 0; } if (data.size() == 0) { //Return 1 here to show nothing return 1; } // Add extra view to show the footer view return data.size() + 1; } // Now define getItemViewType of your own. @Override public int getItemViewType(int position) { if (position == data.size()) { // This is where we'll add footer. return FOOTER_VIEW; } return super.getItemViewType(position); } // So you're done with adding a footer and its action on onClick. // Now set the default ViewHolder for NormalViewHolder public class ViewHolder extends RecyclerView.ViewHolder { // Define elements of a row here public ViewHolder(View itemView) { super(itemView); // Find view by ID and initialize here } public void bindView(int position) { // bindView() method to implement actions } } }
回答2:
I had the same problem on Lollipop and created two approaches to wrap the Recyclerview adapter. One is pretty easy to use, but I'm not sure how it will behave with a changing dataset. Because it wraps your adapter and you need to make yourself sure to call methods like notifyDataSetChanged on the right adapter-object.
The other shouldn't have such problems. Just let your regular adapter extend the class, implement the abstract methods and you should be ready. And here they are:
gists
HeaderRecyclerViewAdapterV1
import android.support.v7.widget.RecyclerView; import android.view.ViewGroup; /** * Created by sebnapi on 08.11.14. * * This is a Plug-and-Play Approach for adding a Header or Footer to * a RecyclerView backed list * * Just wrap your regular adapter like this * * new HeaderRecyclerViewAdapterV1(new RegularAdapter()) * * Let RegularAdapter implement HeaderRecyclerView, FooterRecyclerView or both * and you are ready to go. * * I'm absolutely not sure how this will behave with changes in the dataset. * You can always wrap a fresh adapter and make sure to not change the old one or * use my other approach. * * With the other approach you need to let your Adapter extend HeaderRecyclerViewAdapterV2 * (and therefore change potentially more code) but possible omit these shortcomings. * * TOTALLY UNTESTED - USE WITH CARE - HAVE FUN :) */ public class HeaderRecyclerViewAdapterV1 extends RecyclerView.Adapter { private static final int TYPE_HEADER = Integer.MIN_VALUE; private static final int TYPE_FOOTER = Integer.MIN_VALUE + 1; private static final int TYPE_ADAPTEE_OFFSET = 2; private final RecyclerView.Adapter mAdaptee; public HeaderRecyclerViewAdapterV1(RecyclerView.Adapter adaptee) { mAdaptee = adaptee; } public RecyclerView.Adapter getAdaptee() { return mAdaptee; } @Override public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { if (viewType == TYPE_HEADER && mAdaptee instanceof HeaderRecyclerView) { return ((HeaderRecyclerView) mAdaptee).onCreateHeaderViewHolder(parent, viewType); } else if (viewType == TYPE_FOOTER && mAdaptee instanceof FooterRecyclerView) { return ((FooterRecyclerView) mAdaptee).onCreateFooterViewHolder(parent, viewType); } return mAdaptee.onCreateViewHolder(parent, viewType - TYPE_ADAPTEE_OFFSET); } @Override public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { if (position == 0 && holder.getItemViewType() == TYPE_HEADER && useHeader()) { ((HeaderRecyclerView) mAdaptee).onBindHeaderView(holder, position); } else if (position == mAdaptee.getItemCount() && holder.getItemViewType() == TYPE_FOOTER && useFooter()) { ((FooterRecyclerView) mAdaptee).onBindFooterView(holder, position); } else { mAdaptee.onBindViewHolder(holder, position - (useHeader() ? 1 : 0)); } } @Override public int getItemCount() { int itemCount = mAdaptee.getItemCount(); if (useHeader()) { itemCount += 1; } if (useFooter()) { itemCount += 1; } return itemCount; } private boolean useHeader() { if (mAdaptee instanceof HeaderRecyclerView) { return true; } return false; } private boolean useFooter() { if (mAdaptee instanceof FooterRecyclerView) { return true; } return false; } @Override public int getItemViewType(int position) { if (position == 0 && useHeader()) { return TYPE_HEADER; } if (position == mAdaptee.getItemCount() && useFooter()) { return TYPE_FOOTER; } if (mAdaptee.getItemCount() >= Integer.MAX_VALUE - TYPE_ADAPTEE_OFFSET) { new IllegalStateException("HeaderRecyclerViewAdapter offsets your BasicItemType by " + TYPE_ADAPTEE_OFFSET + "."); } return mAdaptee.getItemViewType(position) + TYPE_ADAPTEE_OFFSET; } public static interface HeaderRecyclerView { public RecyclerView.ViewHolder onCreateHeaderViewHolder(ViewGroup parent, int viewType); public void onBindHeaderView(RecyclerView.ViewHolder holder, int position); } public static interface FooterRecyclerView { public RecyclerView.ViewHolder onCreateFooterViewHolder(ViewGroup parent, int viewType); public void onBindFooterView(RecyclerView.ViewHolder holder, int position); } }
HeaderRecyclerViewAdapterV2
import android.support.v7.widget.RecyclerView; import android.view.ViewGroup; /** * Created by sebnapi on 08.11.14. * * If you extend this Adapter you are able to add a Header, a Footer or both * by a similar ViewHolder pattern as in RecyclerView. * * If you want to omit changes to your class hierarchy you can try the Plug-and-Play * approach HeaderRecyclerViewAdapterV1. * * Don't override (Be careful while overriding) * - onCreateViewHolder * - onBindViewHolder * - getItemCount * - getItemViewType * * You need to override the abstract methods introduced by this class. This class * is not using generics as RecyclerView.Adapter make yourself sure to cast right. * * TOTALLY UNTESTED - USE WITH CARE - HAVE FUN :) */ public abstract class HeaderRecyclerViewAdapterV2 extends RecyclerView.Adapter { private static final int TYPE_HEADER = Integer.MIN_VALUE; private static final int TYPE_FOOTER = Integer.MIN_VALUE + 1; private static final int TYPE_ADAPTEE_OFFSET = 2; @Override public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { if (viewType == TYPE_HEADER) { return onCreateHeaderViewHolder(parent, viewType); } else if (viewType == TYPE_FOOTER) { return onCreateFooterViewHolder(parent, viewType); } return onCreateBasicItemViewHolder(parent, viewType - TYPE_ADAPTEE_OFFSET); } @Override public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { if (position == 0 && holder.getItemViewType() == TYPE_HEADER) { onBindHeaderView(holder, position); } else if (position == getBasicItemCount() && holder.getItemViewType() == TYPE_FOOTER) { onBindFooterView(holder, position); } else { onBindBasicItemView(holder, position - (useHeader() ? 1 : 0)); } } @Override public int getItemCount() { int itemCount = getBasicItemCount(); if (useHeader()) { itemCount += 1; } if (useFooter()) { itemCount += 1; } return itemCount; } @Override public int getItemViewType(int position) { if (position == 0 && useHeader()) { return TYPE_HEADER; } if (position == getBasicItemCount() && useFooter()) { return TYPE_FOOTER; } if (getBasicItemType(position) >= Integer.MAX_VALUE - TYPE_ADAPTEE_OFFSET) { new IllegalStateException("HeaderRecyclerViewAdapter offsets your BasicItemType by " + TYPE_ADAPTEE_OFFSET + "."); } return getBasicItemType(position) + TYPE_ADAPTEE_OFFSET; } public abstract boolean useHeader(); public abstract RecyclerView.ViewHolder onCreateHeaderViewHolder(ViewGroup parent, int viewType); public abstract void onBindHeaderView(RecyclerView.ViewHolder holder, int position); public abstract boolean useFooter(); public abstract RecyclerView.ViewHolder onCreateFooterViewHolder(ViewGroup parent, int viewType); public abstract void onBindFooterView(RecyclerView.ViewHolder holder, int position); public abstract RecyclerView.ViewHolder onCreateBasicItemViewHolder(ViewGroup parent, int viewType); public abstract void onBindBasicItemView(RecyclerView.ViewHolder holder, int position); public abstract int getBasicItemCount(); /** * make sure you don't use [Integer.MAX_VALUE-1, Integer.MAX_VALUE] as BasicItemViewType * * @param position * @return */ public abstract int getBasicItemType(int position); }
Feedback and forks appreciated. I will use HeaderRecyclerViewAdapterV2 by my self and evolve, test and post the changes in the future.
EDIT: @OvidiuLatcu Yes I had some problems. Actually I stopped offsetting the Header implicitly by position - (useHeader() ? 1 : 0) and instead created a public method int offsetPosition(int position) for it. Because if you set an OnItemTouchListener on Recyclerview, you can intercept the touch, get the x,y coordinates of the touch, find the according child view and then call recyclerView.getChildPosition(...)and you will always get the non-offsetted position in the adapter! This is a shortcomming in the RecyclerView Code, I don't see an easy method to overcome this. This is why I now offset the positions explicit when I need to by my own code.
回答3:
Very simple to solve!!
I don't like an idea of having logic inside adapter as a different view type because every time it checks for the view type before returning the view. Below solution avoids extra checks.
Just add LinearLayout (vertical) header view + recyclerview + footer view inside android.support.v4.widget.NestedScrollView.
Check this out:
Add this line of code for smooth scrolling
RecyclerView v = (RecyclerView) findViewById(...); v.setNestedScrollingEnabled(false);
P.S To retain recycling advantage of recycleview, keep its height wrap_content . See my twitter thread!
回答4:
I haven't tried this, but I would simply add 1 (or 2, if you want both a header and footer) to the integer returned by getItemCount in your adapter. You can then override getItemViewType in your adapter to return a different integer when i==0: https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter.html#getItemViewType(int)
createViewHolder is then passed the integer you returned from getItemViewType, allowing you to create or configure the view holder differently for the header view: https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter.html#createViewHolder(android.view.ViewGroup, int)
Don't forget to subtract one from the position integer passed to bindViewHolder.
回答5:
You can used this GitHub library allowing to add Header and/or Footer in your RecyclerView in the simplest way possible.
You need to add HFRecyclerView library in your project or you can also grab it from Gradle:
compile 'com.mikhaellopez:hfrecyclerview:1.0.0'
This is a result in image:
EDIT:
If you just want to add a margin at the top and/or bottom with this library: SimpleItemDecoration:
int offsetPx = 10; recyclerView.addItemDecoration(new StartOffsetItemDecoration(offsetPx)); recyclerView.addItemDecoration(new EndOffsetItemDecoration(offsetPx));
回答6:
I ended up implementing my own adapter to wrap any other adapter and provide methods to add header and footer views.
Created a gist here: HeaderViewRecyclerAdapter.java
The main feature I wanted was a similar interface to a ListView, so I wanted to be able to inflate the views in my Fragment and add them to the RecyclerView in onCreateView. This is done by creating a HeaderViewRecyclerAdapter passing the adapter to be wrapped, and calling addHeaderView and addFooterView passing your inflated views. Then set the HeaderViewRecyclerAdapter instance as the adapter on the RecyclerView.
An extra requirement was that I needed to be able to easily swap out adapters while keeping the headers and footers, I didn't want to have multiple adapters with multiple instances of these headers and footers. So you can call setAdapter to change the wrapped adapter leaving the headers and footers intact, with the RecyclerView being notified of the change.
回答7:
Based on @seb's solution, I created a subclass of RecyclerView.Adapter that supports an arbitrary number of headers and footers.
https://gist.github.com/mheras/0908873267def75dc746
Although it seems to be a solution, I also think this thing should be managed by the LayoutManager. Unfortunately, I need it now and I don't have time to implement a StaggeredGridLayoutManager from scratch (nor even extend from it).
I'm still testing it, but you can try it out if you want. Please let me know if you find any issues with it.
回答8:
You can use viewtype to solve this problem, here is my demo: https://github.com/yefengfreedom/RecyclerViewWithHeaderFooterLoadingEmptyViewErrorView
you can define some recycler view display mode:
public static final int MODE_DATA = 0, MODE_LOADING = 1, MODE_ERROR = 2, MODE_EMPTY = 3, MODE_HEADER_VIEW = 4, MODE_FOOTER_VIEW = 5;
2.override the getItemViewType mothod
@Override public int getItemViewType(int position) { if (mMode == RecyclerViewMode.MODE_LOADING) { return RecyclerViewMode.MODE_LOADING; } if (mMode == RecyclerViewMode.MODE_ERROR) { return RecyclerViewMode.MODE_ERROR; } if (mMode == RecyclerViewMode.MODE_EMPTY) { return RecyclerViewMode.MODE_EMPTY; } //check what type our position is, based on the assumption that the order is headers > items > footers if (position = mHeaders.size() + mData.size()) { return RecyclerViewMode.MODE_FOOTER_VIEW; } return RecyclerViewMode.MODE_DATA; }
3.override the getItemCount method
@Override public int getItemCount() { if (mMode == RecyclerViewMode.MODE_DATA) { return mData.size() + mHeaders.size() + mFooters.size(); } else { return 1; } }
4.override the onCreateViewHolder method. create view holder by viewType
@Override public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { if (viewType == RecyclerViewMode.MODE_LOADING) { RecyclerView.ViewHolder loadingViewHolder = onCreateLoadingViewHolder(parent); loadingViewHolder.itemView.setLayoutParams( new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, parent.getHeight() - mToolBarHeight) ); return loadingViewHolder; } if (viewType == RecyclerViewMode.MODE_ERROR) { RecyclerView.ViewHolder errorViewHolder = onCreateErrorViewHolder(parent); errorViewHolder.itemView.setLayoutParams( new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, parent.getHeight() - mToolBarHeight) ); errorViewHolder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(final View v) { if (null != mOnErrorViewClickListener) { new Handler().postDelayed(new Runnable() { @Override public void run() { mOnErrorViewClickListener.onErrorViewClick(v); } }, 200); } } }); return errorViewHolder; } if (viewType == RecyclerViewMode.MODE_EMPTY) { RecyclerView.ViewHolder emptyViewHolder = onCreateEmptyViewHolder(parent); emptyViewHolder.itemView.setLayoutParams( new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, parent.getHeight() - mToolBarHeight) ); emptyViewHolder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(final View v) { if (null != mOnEmptyViewClickListener) { new Handler().postDelayed(new Runnable() { @Override public void run() { mOnEmptyViewClickListener.onEmptyViewClick(v); } }, 200); } } }); return emptyViewHolder; } if (viewType == RecyclerViewMode.MODE_HEADER_VIEW) { RecyclerView.ViewHolder headerViewHolder = onCreateHeaderViewHolder(parent); headerViewHolder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(final View v) { if (null != mOnHeaderViewClickListener) { new Handler().postDelayed(new Runnable() { @Override public void run() { mOnHeaderViewClickListener.onHeaderViewClick(v, v.getTag()); } }, 200); } } }); return headerViewHolder; } if (viewType == RecyclerViewMode.MODE_FOOTER_VIEW) { RecyclerView.ViewHolder footerViewHolder = onCreateFooterViewHolder(parent); footerViewHolder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(final View v) { if (null != mOnFooterViewClickListener) { new Handler().postDelayed(new Runnable() { @Override public void run() { mOnFooterViewClickListener.onFooterViewClick(v, v.getTag()); } }, 200); } } }); return footerViewHolder; } RecyclerView.ViewHolder dataViewHolder = onCreateDataViewHolder(parent); dataViewHolder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(final View v) { if (null != mOnItemClickListener) { new Handler().postDelayed(new Runnable() { @Override public void run() { mOnItemClickListener.onItemClick(v, v.getTag()); } }, 200); } } }); dataViewHolder.itemView.setOnLongClickListener(new View.OnLongClickListener() { @Override public boolean onLongClick(final View v) { if (null != mOnItemLongClickListener) { new Handler().postDelayed(new Runnable() { @Override public void run() { mOnItemLongClickListener.onItemLongClick(v, v.getTag()); } }, 200); return true; } return false; } }); return dataViewHolder; }
5.Override the onBindViewHolder method. bind data by viewType
@Override public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { if (mMode == RecyclerViewMode.MODE_LOADING) { onBindLoadingViewHolder(holder, position); } else if (mMode == RecyclerViewMode.MODE_ERROR) { onBindErrorViewHolder(holder, position); } else if (mMode == RecyclerViewMode.MODE_EMPTY) { onBindEmptyViewHolder(holder, position); } else { if (position 0) { onBindHeaderViewHolder(holder, position); } } else if (position >= mHeaders.size() + mData.size()) { if (mFooters.size() > 0) { onBindFooterViewHolder(holder, position - mHeaders.size() - mData.size()); } } else { onBindDataViewHolder(holder, position - mHeaders.size()); } } }
回答9:
I know I come late, but only recently I was able to implement such "addHeader" to the Adapter. In my FlexibleAdapter project you can call setHeader on a Sectionable item, then you call showAllHeaders. If you need only 1 header then the first item should have the header. If you delete this item, then the header is automatically linked to the next one.
Unfortunately footers are not covered (yet).
The FlexibleAdapter allows you to do much more than create headers/sections. You really should have a look: https://github.com/davideas/FlexibleAdapter.
回答10:
You can use the library SectionedRecyclerViewAdapter to group your items in sections and add a header to each section, like on the image below:
First you create your section class:
class MySection extends StatelessSection { String title; List list; public MySection(String title, List list) { // call constructor with layout resources for this Section header, footer and items super(R.layout.section_header, R.layout.section_item); this.title = title; this.list = list; } @Override public int getContentItemsTotal() { return list.size(); // number of items of this section } @Override public RecyclerView.ViewHolder getItemViewHolder(View view) { // return a custom instance of ViewHolder for the items of this section return new MyItemViewHolder(view); } @Override public void onBindItemViewHolder(RecyclerView.ViewHolder holder, int position) { MyItemViewHolder itemHolder = (MyItemViewHolder) holder; // bind your view here itemHolder.tvItem.setText(list.get(position)); } @Override public RecyclerView.ViewHolder getHeaderViewHolder(View view) { return new SimpleHeaderViewHolder(view); } @Override public void onBindHeaderViewHolder(RecyclerView.ViewHolder holder) { MyHeaderViewHolder headerHolder = (MyHeaderViewHolder) holder; // bind your header view here headerHolder.tvItem.setText(title); } }
Then you set up the RecyclerView with your sections and change the SpanSize of the headers with a GridLayoutManager:
// Create an instance of SectionedRecyclerViewAdapter SectionedRecyclerViewAdapter sectionAdapter = new SectionedRecyclerViewAdapter(); // Create your sections with the list of data MySection section1 = new MySection("My Section 1 title", dataList1); MySection section2 = new MySection("My Section 2 title", dataList2); // Add your Sections to the adapter sectionAdapter.addSection(section1); sectionAdapter.addSection(section2); // Set up a GridLayoutManager to change the SpanSize of the header GridLayoutManager glm = new GridLayoutManager(getContext(), 2); glm.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() { @Override public int getSpanSize(int position) { switch(sectionAdapter.getSectionItemViewType(position)) { case SectionedRecyclerViewAdapter.VIEW_TYPE_HEADER: return 2; default: return 1; } } }); // Set up your RecyclerView with the SectionedRecyclerViewAdapter RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview); recyclerView.setLayoutManager(glm); recyclerView.setAdapter(sectionAdapter);
回答11:
I would just add an alternative to all those HeaderRecyclerViewAdapter implementation. CompoundAdapter:
https://github.com/negusoft/CompoundAdapter-android
It is a more flexible approach, since you can create a AdapterGroup out of Adapters. For the header example, use your adapter as it is, along with an adapter containing one item for the header:
AdapterGroup adapterGroup = new AdapterGroup(); adapterGroup.addAdapter(SingleAdapter.create(R.layout.header)); adapterGroup.addAdapter(new MyAdapter(...)); recyclerView.setAdapter(adapterGroup);
It is fairly simple and readable. You can implement more complex adapter easily using the same principle.
