我正在开发一个严重依赖 RecyclerView 使用的应用程序。
我真的需要知道如何为不同的项目布局使用相同的 RecyclerView。布局示例如下：
1) 带有名称和描述的列表项
2) 带有图像和名称的列表项
您可以看到它们相似，但布局略有不同。
提前致谢！
【问题讨论】：
标签： android android-recyclerview
由于 xml 中的 recyclerview 项目不依赖于您将在其中膨胀的项目类型，您可以继续为三个片段使用相同的 recycler view 布局文件。
至于适配器，您的列表似乎是同质的（即单一类型的视图项）。最好为每种情况使用 3 个不同的适配器。您可以自定义构造函数，根据您的方便为每种适配器添加自定义帮助方法。
现在，如果您有一个异构列表，则必须在适配器中覆盖 getItemViewType() 并在 onCreateViewHolder() 和 onBindViewHolder() 中适当地使用它
希望这会有所帮助！ :)
【讨论】：
我遇到过类似的情况，这是我遵循的模式。
首先，片段布局文件。
3个片段的片段布局文件都不会改变（基本上和列表片段类似），所以我为列表片段创建了一个模板文件。
list_fragment_template.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</FrameLayout>
现在片段代码：
在我的例子中，所有 3 个片段都做几乎相同的事情（获取回收器视图、获取适配器、回收器视图装饰和一些其他操作等）。
创建了一个扩展片段的 AbstrctFragment 并覆盖了 onCreate onAttach onDestroy 等。由于只有类型的数据 recyclerview 消耗和适配器将数据推送到 recycelrview 会改变每个片段，创建一个抽象函数来获取适配器和模板化数据。这三个片段中的每一个都将派生自这个 AbstractFragment。
public abstract class AbstractFragment<E> extends Fragment {
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.template_list_fragment, container, false);
mRecyclerView = (RecyclerView) view.findViewById(R.id.list);
// get adapter to show item list
// and fetch data.
mRecyclerAdapter = getAdapter();
mRecyclerView.setAdapter(mRecyclerAdapter);
// show it as vertical list
mRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
// add seperator between list items.
mRecyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL_LIST));
return view;
}
... onAttach onDetach 以及每个片段的任何常见成员函数和成员变量。
现在 RecyclerView 布局文件。由于它们的布局不同，显然它们一定是不同的。
RecyclerViewAdapters：同样，这里的通用代码是成员声明、CreateViewHolder（这里只有布局名称更改，所有代码都相同）和所有这些适配器共享的任何其他函数。 （类似于过滤列表项）。
与我们对片段所做的类似，您可以将其保留在 AbstractRecyclerViewAdapter 中，并将 bindViewholder 等作为抽象函数，并拥有 3 个不同的 recyclerAdapter 派生自此 AbstractRecyclerViewAdapter..
【讨论】：
为时已晚，但可能对有需要的开发人员有所帮助 您的适配器应如下所示，您也可以使用此示例添加页眉和页脚
public class SampleAdapter extends RecyclerView.Adapter<SampleAdapter.ViewHolder> {
// Declaring Variable to Understand which View is being worked on
// IF the view under inflation and population is header or Item
private static final int TYPE_HEADER = 0;
private static final int TYPE_ITEM = 1;
private static final int TYPE_FOOTER = 2;
private Activity mContext;
private ArrayList<DataModel> _mItems;
private int mLayout;
private String mProductHeadingTitle="Heading";
private String mProductHeadingSubTitle="SubHeading";
private String loadingText="LOADING";
private int visibility= View.VISIBLE;
public interface SampleAdapterInterface {
void itemClicked(int position);
}
SampleAdapterInterface mCallBack;
public SampleAdapter(Activity context, ArrayList<DataModel> items, int item_layout) {
if (_mItems != null) {
_mItems.clear();
}
this.mContext = context;
this._mItems = items;
this.mLayout = item_layout;
mCallBack = (SampleAdapterInterface) context;
}
@Override
public int getItemCount() {
return _mItems.size()+2; // +2 for header and footer
}
@Override
public int getItemViewType(int position) {
if (position==0)
return TYPE_HEADER;
else if(position==(_mItems.size()+1))
return TYPE_FOOTER;
return TYPE_ITEM;
}
public void setHeaderData(String title,String subTitle)
{
this.mProductHeadingTitle=title;
this.mProductHeadingSubTitle=subTitle;
Log.d("LOG", "ProductHeadingTitle: " + mProductHeadingTitle);
Log.d("LOG", "ProductHeadingSubTitle: " + mProductHeadingSubTitle);
notifyDataSetChanged();
}
public void setFooterData(String loadingText,int visibility)
{
this.loadingText=loadingText;
this.visibility=visibility;
Log.d("LOG", "LoadingText: " + loadingText);
Log.d("LOG", "Visibility: " + visibility);
notifyDataSetChanged();
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == TYPE_HEADER)
{
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.header_layout,parent,false);
ViewHolder vhHeader = new ViewHolder(view,viewType);
return vhHeader;
}
else if (viewType == TYPE_ITEM)
{
View view = LayoutInflater.from(parent.getContext()).inflate(mLayout,parent,false);
//Creating ViewHolder and passing the object of type view
ViewHolder vhItem = new ViewHolder(view,viewType);
return vhItem;
}
else if (viewType == TYPE_FOOTER)
{
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.footer_lyout,parent,false);
ViewHolder vhFooter = new ViewHolder(view,viewType);
return vhFooter;
}
return null;
}
@Override
public void onBindViewHolder(ViewHolder viewHolder, int pos) {
if(viewHolder.Holderid ==0)
{
// header view
Log.d("LOG", "in header binder");
viewHolder.mProductCatalogTitle.setText(mProductHeadingTitle);
viewHolder.mProductCatalogSubTitle.setText(mProductHeadingSubTitle);
}
else if(viewHolder.Holderid==1)
{
final int position=pos-1; // -1 to substract header number
// your code
}
else if(viewHolder.Holderid==2)
{
// footer
Log.d("LOG", "in footer binder");
viewHolder.mProgressBar.setVisibility(visibility);
viewHolder.mLoading.setText(loadingText);
}
}
class ViewHolder extends RecyclerView.ViewHolder {
int Holderid;
// header
TextView mProductCatalogTitle;
TextView mProductCatalogSubTitle;
//list
// item type variable declaration
// footer
ProgressBar mProgressBar;
TextView mLoading;
public ViewHolder(View itemView, int viewType) {
super(itemView);
// Here we set the appropriate view in accordance with the the view type as passed when the holder object is created
if(viewType == TYPE_HEADER)
{
Holderid = 0;
mProductCatalogTitle = (TextView) itemView.findViewById(R.id.tv_title);
mProductCatalogSubTitle = (TextView) itemView.findViewById(R.id.tv_subtitle);
}
else if(viewType == TYPE_ITEM)
{
Holderid = 1;
itemView.setClickable(true);
itemView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mCallBack.itemClicked(getAdapterPosition()-1);
}
});
// initialize the view holder
}
else if(viewType == TYPE_FOOTER)
{
Holderid = 2;
mLoading = (TextView) itemView.findViewById(R.id.tv_loading);
mProgressBar = (ProgressBar) itemView.findViewById(R.id.progress_bar);
}
}
}
在你的活动中
// Adding to adapter as gridview when grid button clicked
private void setProductGridAdapter() {
mListViewTab.setVisibility(View.VISIBLE);
mGridViewTab.setVisibility(View.INVISIBLE);
mSampleAdapter = new SampleAdapter(YourActicity.this,
yourlist,R.layout.item_product_grid);
mRecyclerView.setAdapter(mSampleAdapter);
mRecyclerView.setHasFixedSize(true);
final GridLayoutManager layoutManager = new GridLayoutManager(getActivity(),
2, //number of columns
LinearLayoutManager.VERTICAL, // orientation
false); //reverse layout
mRecyclerView.setLayoutManager(layoutManager);
layoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
// to show header and footer in full row
if(position==0 || position==(yourlist.size()+1))
return layoutManager.getSpanCount();
else
return 1;
}
});
mRecyclerView.scrollToPosition(AppController.currentPosition);
mSampleAdapter.notifyDataSetChanged();
// Scroll listener for RecyclerView to call load more products
mRecyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
int visibleItemCount = layoutManager.getChildCount();
int totalItemCount = layoutManager.getItemCount();
int firstVisibleItem = layoutManager.findFirstVisibleItemPosition();
int lastInScreen = firstVisibleItem + visibleItemCount;
if ((lastInScreen >= totalItemCount) && !isLoading) {
//last item
// do something after last item like load more code or
// show No more items string
mSampleAdapter.setFooterData("NO More Items",View.INVISIBLE);
}
AppController.currentPosition = firstVisibleItem;
}
});
}
// Adding to adapter as listview when list button clicked
private void setProductListAdapter() {
mListViewTab.setVisibility(View.INVISIBLE);
mGridViewTab.setVisibility(View.VISIBLE);
mSampleAdapter = new SampleAdapter(YourActicity.this, yourlist,R.layout.item_product_list);
mRecyclerView.setAdapter(mSampleAdapter);
mRecyclerView.setHasFixedSize(true);
final LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity(),
LinearLayoutManager.VERTICAL, // orientation
false); //reverse layout
mRecyclerView.setLayoutManager(layoutManager);
mRecyclerView.scrollToPosition(AppController.currentPosition);
mSampleAdapter.notifyDataSetChanged();
// Scroll listener for RecyclerView to call load more products
mRecyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
int visibleItemCount = layoutManager.getChildCount();
int totalItemCount = layoutManager.getItemCount();
int firstVisibleItem = layoutManager.findFirstVisibleItemPosition();
int lastInScreen = firstVisibleItem + visibleItemCount;
if ((lastInScreen >= totalItemCount) && !isLoading) {
//last item
// do something after last item like load more code or
// show No more items string
mSampleAdapter.setFooterData("NO MOre Items",View.INVISIBLE);
}
AppController.currentPosition = firstVisibleItem;
}
});
}
并且您的活动必须在活动中实现 SampleAdapterInterface 才能从适配器获取回调。 将按钮从网格切换到列表时调用这些方法，反之亦然
【讨论】：
//To setViewType maybe is a solution for you.Sample below:
private static final int TYPE_DESC = 0;
private static final int TYPE_IMAGE = TYPE_DESC + 1;
private static final int TYPE_THREE_TEXT = TYPE_IMAGE + 1;
public int getItemViewType(int position) {
int type = super.getItemViewType(position);
try
{
type = Integer.parseInt(data.get(position).get("type"));
} catch (Exception e)
{
e.printStackTrace();
}
return type;
}
public int getViewTypeCount() {
return 3;
}
public View getView(int position, View convertView, ViewGroup parent) {
int type = TYPE_DESC;
try
{
type = Integer.parseInt(data.get(position).get("type"));
} catch (Exception e)
{
e.printStackTrace();
}
ViewHolder holder = null;
if (convertView == null)
{
System.out.println("getView::convertView is null");
holder = new ViewHolder();
switch (type)
{
case TYPE_DESC:
convertView = View.inflate(getBaseContext(),
R.layout.listitem_1, null);
break;
case TYPE_IMAGE:
convertView = View.inflate(getBaseContext(),
R.layout.listitem_2, null);
break;
case TYPE_THREE_TEXT:
convertView = View.inflate(getBaseContext(),
R.layout.listitem_3, null);
break;
}
convertView.setTag(holder);
}
else
{
holder = (ViewHolder) convertView.getTag();
}
//TODO
return convertView;
}
【讨论】：