header 中带有嵌套可扩展列表的 Recyclerview
Recycleview with nested expandable lists in header
我正在设计一个比较复杂的UI，我搜索了Whosebug并没有找到类似的设计。可能有很多方法可以解决这个问题，但我想就如何实现这一点征求专家意见，我想分享我的方法并确保我以正确的方式进行。我的方法是，我使用 header 创建了一个回收视图，在 header 回收视图中，我正在使用由 h6ah4i (taken from github) 开发的可扩展回收视图库。如果有更好的方法，请告诉我。
下面的图片预览是我想要得到的最终结果的实时模型。这不是实际的屏幕。我的问题是实现此目标的最佳方法是什么，我应该在 recycleview header 中使用可扩展的 recycleview 还是可扩展的列表视图。我感谢任何答案，因为它不必与我的代码相似。欢迎任何建议。我希望这个 post 也能帮助像我一样的其他人寻找类似的解决方案。
RecycleView 适配器
public class RecycleAdapterPlantSearch extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static final int TYPE_HEADER = 0;
private static final int TYPE_ITEM = 1;
private List<Plants> plantsList;
private Context context;
private OnItemClickListener onItemClickListener;
public RecycleAdapterPlantSearch(Context context, List<Plants> plantsList, OnItemClickListener onClickListener) {
this.context = context;
this.plantsList = plantsList;
onItemClickListener = onClickListener;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == TYPE_ITEM) {
// Here Inflating your recyclerview item layout
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_view_plant_search_plant_item, parent, false);
return new ItemViewHolder(itemView, onItemClickListener);
} else if (viewType == TYPE_HEADER) {
// Here Inflating your header view
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_view_plant_search_header, parent, false);
return new HeaderViewHolder(itemView, onItemClickListener);
} else return null;
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
/*
position 0 is for header
*/
if (holder instanceof HeaderViewHolder) {
// setheadersdata_flag = true;
HeaderViewHolder headerViewHolder = (HeaderViewHolder) holder;
// You have to set your header items values with the help of model class and you can modify as per your needs
// Setup expandable feature and RecyclerView
RecyclerViewExpandableItemManager expMgr = new RecyclerViewExpandableItemManager(null);
SimpleDemoExpandableItemAdapter.OnListItemClickMessageListener clickListener = message -> {
Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
};
List<BadgesVM> badgesVMList = null;
badgesVMList = new ArrayList() {{
add(new BadgesVM("447", "Bienenfreundlich", "bienenfreundlich", false));
add(new BadgesVM("320,322", "Vogelfreundlich", "vogelfreundlich", false));
add(new BadgesVM("321", "Insektenfreundlich", "insektenfreundlich", false));
add(new BadgesVM("445", "Ökologisch wertvoll", "oekologisch", false));
add(new BadgesVM("531", "Schmetterlings freundlich", "schmetterlings", false));
add(new BadgesVM("530", "Heimische Pflanze'", "heimische Pflanze'", false));
}};
// Create wrapped adapter: MyItemAdapter -> expMgr.createWrappedAdapter -> MyHeaderFooterAdapter
RecyclerView.Adapter adapter;
adapter = new SimpleDemoExpandableItemAdapter(context, expMgr,badgesVMList, clickListener);
adapter = expMgr.createWrappedAdapter(adapter);
//adapter = new DemoHeaderFooterAdapter(adapter, null);
headerViewHolder.recyclerViewExpandable.setAdapter(adapter);
headerViewHolder.recyclerViewExpandable.setLayoutManager(new LinearLayoutManager(context));
// NOTE: need to disable change animations to ripple effect work properly
((SimpleItemAnimator) headerViewHolder.recyclerViewExpandable.getItemAnimator()).setSupportsChangeAnimations(false);
expMgr.attachRecyclerView(headerViewHolder.recyclerViewExpandable);
} else if (holder instanceof ItemViewHolder) {
final ItemViewHolder itemViewHolder = (ItemViewHolder) holder;
itemViewHolder.plantDescText.setText(plantsList.get(position - 1).getDescription());
RequestOptions options = new RequestOptions()
.centerCrop()
.placeholder(R.drawable.background_small);
String imageUrl = APP_URL.BASE_ROUTE_INTERN + plantsList.get(position - 1).getImages().get(0).getSrcAttr();
Glide.with(context).load(imageUrl).apply(options).into(itemViewHolder.plantImg);
}
}
@Override
public int getItemViewType(int position) {
if (position == 0) {
return TYPE_HEADER;
}
return TYPE_ITEM;
}
@Override
public long getItemId(int position) {
return position;
}
// getItemCount increasing the position to 1. This will be the row of header
@Override
public int getItemCount() {
return plantsList.size() + 1;
}
public interface OnItemClickListener {
void OnItemClickListener(View view, int position);
void RecycleViewExtraDetails(ChipGroup chipGroup);
void nestedRecycleViewsSpecialOdd(RecyclerView nestedRecycleView);
}
private class HeaderViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private TextView searchNameTxt, searchFamilyTxt, plantGroupTxt, plantFamilySearchTxt, ecologyFilterTxt,
frostSearchTxt;
private ChipGroup chipGroup;
private Button filterSearchBtn;
private CardView ecologyCv;
private CardView detailSearchCv;
private RecyclerView recyclerViewExpandable;
public HeaderViewHolder(View headerView, OnItemClickListener onItemClickListener) {
super(headerView);
searchNameTxt = headerView.findViewById(R.id.textView_plant_search_header_plant_search);
searchFamilyTxt = headerView.findViewById(R.id.textView_plant_search_header_plant_search);
ecologyCv = headerView.findViewById(R.id.cardView_plant_search_header_ecology);
detailSearchCv = headerView.findViewById(R.id.cardView_plant_search_header_detail_search);
plantGroupTxt = headerView.findViewById(R.id.textView_plant_search_header_plant_group);
plantFamilySearchTxt = headerView.findViewById(R.id.textView_plant_search_header_plant_family);
ecologyFilterTxt = headerView.findViewById(R.id.textView_plant_search_header_ecology_filter);
frostSearchTxt = headerView.findViewById(R.id.textView_plant_search_header_frost_filter);
chipGroup = headerView.findViewById(R.id.chip_group_plant_search_header);
filterSearchBtn = headerView.findViewById(R.id.button_plant_search_header_filter_search);
recyclerViewExpandable = headerView.findViewById(R.id.expandable_list_view_plant_search);
searchNameTxt.setOnClickListener(this);
searchFamilyTxt.setOnClickListener(this);
ecologyCv.setOnClickListener(this);
detailSearchCv.setOnClickListener(this);
plantGroupTxt.setOnClickListener(this);
plantFamilySearchTxt.setOnClickListener(this);
ecologyFilterTxt.setOnClickListener(this);
filterSearchBtn.setOnClickListener(this);
frostSearchTxt.setOnClickListener(this);
}
@Override
public void onClick(View view) {
onItemClickListener.OnItemClickListener(view, getAdapterPosition());
onItemClickListener.RecycleViewExtraDetails(chipGroup);
}
}
public class ItemViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private Button readMoreBtn;
private TextView plantDescText;
private ImageView plantImg;
public ItemViewHolder(View itemView, OnItemClickListener onItemClickListener) {
super(itemView);
plantDescText = itemView.findViewById(R.id.textView_plant_search_plants_item_description_text);
readMoreBtn = itemView.findViewById(R.id.button_plant_search_plant_item_read_more);
plantImg = itemView.findViewById(R.id.imageView_plant_search_plants_item_plant_image);
readMoreBtn.setOnClickListener(this);
}
@Override
public void onClick(View view) {
onItemClickListener.OnItemClickListener(view, getAdapterPosition() - 1);
}
}
}
嵌套header回收视图
public class SimpleDemoExpandableItemAdapter extends AbstractExpandableItemAdapter<SimpleDemoExpandableItemAdapter.MyGroupViewHolder,
SimpleDemoExpandableItemAdapter.MyChildViewHolder> implements View.OnClickListener {
RecyclerViewExpandableItemManager mExpandableItemManager;
List<MyBaseItem> mItems;
OnListItemClickMessageListener mOnItemClickListener;
List<BadgesVM> badgesVMList;
Context context;
static class MyBaseItem {
public final int id;
public final String text;
public MyBaseItem(int id, String text) {
this.id = id;
this.text = text;
}
}
static abstract class MyBaseViewHolder extends AbstractExpandableItemViewHolder {
TextView textView;
Slider frostSlider;
RecyclerView detailRecycleView;
public MyBaseViewHolder(View itemView) {
super(itemView);
textView = itemView.findViewById(android.R.id.text1);
frostSlider = itemView.findViewById(R.id.slider_plant_search_expandable);
detailRecycleView = itemView.findViewById(R.id.recycle_view_plant_search_detail_search);
}
}
static class MyGroupViewHolder extends MyBaseViewHolder {
public MyGroupViewHolder(View itemView) {
super(itemView);
}
}
static class MyChildViewHolder extends MyBaseViewHolder {
public MyChildViewHolder(View itemView) {
super(itemView);
}
}
public SimpleDemoExpandableItemAdapter(Context context, RecyclerViewExpandableItemManager expMgr, List<BadgesVM> badgesVMList, OnListItemClickMessageListener clickListener) {
mExpandableItemManager = expMgr;
mOnItemClickListener = clickListener;
this.badgesVMList = badgesVMList;
this.context = context;
setHasStableIds(true); // this is required for expandable feature.
mItems = new ArrayList<>();
mItems.add(new MyBaseItem(0, "Filter nach ökologischen Kriterien"));
mItems.add(new MyBaseItem(1, "Frosthärte"));
mItems.add(new MyBaseItem(2, "Detailsuche"));
}
@Override
public int getGroupCount() {
return mItems.size();
}
@Override
public int getChildCount(int groupPosition) {
int childCount = 0;
int groupId = mItems.get(groupPosition).id;
if (groupId == 0) {
childCount = badgesVMList.size();
} else if (groupId == 1) {
childCount = 1; //contains only one item
} else if (groupId == 2) {
childCount = 1; //contains only one item
}
return childCount;
}
@Override
public long getGroupId(int groupPosition) {
// This method need to return unique value within all group items.
return mItems.get(groupPosition).id;
}
@Override
public long getChildId(int groupPosition, int childPosition) {
// This method need to return unique value within the group.
int groupId = mItems.get(groupPosition).id;
int childId = 0;
if (groupId == 0) {
badgesVMList.get(childPosition).getId();
} else if (groupId == 1) {
childId = 0;
} else if (groupId == 2) {
childId = 0;
}
return childId;
}
@Override
@NonNull
public MyGroupViewHolder onCreateGroupViewHolder(@NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_group_item_for_expandable_minimal, parent, false);
MyGroupViewHolder vh = new MyGroupViewHolder(v);
vh.itemView.setOnClickListener(this);
return vh;
}
@Override
@NonNull
public MyChildViewHolder onCreateChildViewHolder(@NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_child_item_for_expandable_minimal, parent, false);
MyChildViewHolder vh = new MyChildViewHolder(v);
vh.itemView.setOnClickListener(this);
return vh;
}
@Override
public void onBindGroupViewHolder(@NonNull MyGroupViewHolder holder, int groupPosition, int viewType) {
MyBaseItem group = mItems.get(groupPosition);
holder.textView.setText(group.text);
}
@Override
public void onBindChildViewHolder(@NonNull MyChildViewHolder holder, int groupPosition, int childPosition, int viewType) {
int groupId = mItems.get(groupPosition).id;
if (groupId == 0) {
BadgesVM badgesVM = badgesVMList.get(childPosition);
holder.textView.setVisibility(View.VISIBLE);
holder.frostSlider.setVisibility(View.GONE);
holder.detailRecycleView.setVisibility(View.GONE);
holder.textView.setText(badgesVM.getName());
} else if (groupId == 1) {
holder.textView.setVisibility(View.GONE);
holder.frostSlider.setVisibility(View.VISIBLE);
holder.detailRecycleView.setVisibility(View.GONE);
} else if (groupId == 2) {
holder.textView.setVisibility(View.GONE);
holder.frostSlider.setVisibility(View.GONE);
holder.detailRecycleView.setVisibility(View.VISIBLE);
// Setup expandable feature and RecyclerView
RecyclerViewExpandableItemManager expMgr = new RecyclerViewExpandableItemManager(null);
DetailSearchExpandableItemAdapter.OnListItemClickMessageListener clickListener = message -> {
Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
};
List<BadgesVM> badgesVMList = null;
badgesVMList = new ArrayList() {{
add(new BadgesVM("447", "Bienenfreundlich", "bienenfreundlich", false));
add(new BadgesVM("320,322", "Vogelfreundlich", "vogelfreundlich", false));
add(new BadgesVM("321", "Insektenfreundlich", "insektenfreundlich", false));
add(new BadgesVM("445", "Ökologisch wertvoll", "oekologisch", false));
add(new BadgesVM("531", "Schmetterlings freundlich", "schmetterlings", false));
add(new BadgesVM("530", "Heimische Pflanze'", "heimische Pflanze'", false));
}};
// Create wrapped adapter: MyItemAdapter -> expMgr.createWrappedAdapter -> MyHeaderFooterAdapter
RecyclerView.Adapter adapter2;
adapter2 = new DetailSearchExpandableItemAdapter(context, expMgr, badgesVMList, clickListener);
adapter2 = expMgr.createWrappedAdapter(adapter2);
//adapter = new DemoHeaderFooterAdapter(adapter, null);
holder.detailRecycleView.setAdapter(adapter2);
holder.detailRecycleView.setLayoutManager(new LinearLayoutManager(context));
// NOTE: need to disable change animations to ripple effect work properly
((SimpleItemAnimator) holder.detailRecycleView.getItemAnimator()).setSupportsChangeAnimations(false);
expMgr.attachRecyclerView(holder.detailRecycleView);
}
}
@Override
public boolean onCheckCanExpandOrCollapseGroup(@NonNull MyGroupViewHolder holder, int groupPosition, int x, int y, boolean expand) {
// handles click event manually (to show Snackbar message)
return false;
}
@Override
public void onClick(View v) {
RecyclerView rv = RecyclerViewAdapterUtils.getParentRecyclerView(v);
RecyclerView.ViewHolder vh = rv.findContainingViewHolder(v);
int rootPosition = vh.getAdapterPosition();
if (rootPosition == RecyclerView.NO_POSITION) {
return;
}
// need to determine adapter local flat position like this:
RecyclerView.Adapter rootAdapter = rv.getAdapter();
int localFlatPosition = WrapperAdapterUtils.unwrapPosition(rootAdapter, this, rootPosition);
long expandablePosition = mExpandableItemManager.getExpandablePosition(localFlatPosition);
int groupPosition = RecyclerViewExpandableItemManager.getPackedPositionGroup(expandablePosition);
int childPosition = RecyclerViewExpandableItemManager.getPackedPositionChild(expandablePosition);
String message;
if (childPosition == RecyclerView.NO_POSITION) {
// Clicked item is a group!
// toggle expand/collapse
if (mExpandableItemManager.isGroupExpanded(groupPosition)) {
mExpandableItemManager.collapseGroup(groupPosition);
message = "COLLAPSE: Group " + groupPosition;
} else {
mExpandableItemManager.expandGroup(groupPosition);
message = "EXPAND: Group " + groupPosition;
}
} else {
// Clicked item is a child!
message = "CLICKED: Child " + groupPosition + "-" + childPosition;
}
mOnItemClickListener.onItemClicked(message);
}
public interface OnListItemClickMessageListener {
void onItemClicked(String message);
}
}
您搜索为您完成大部分工作的图书馆是正确的，但我不喜欢您选择的图书馆。它看起来不是很灵活和简洁。我建议查看 Groupie, its API is pretty clean. Also check Reddit 以了解有关库的一些讨论。
如果你想自己写，我想你可以不用嵌套 Adapter 来解决它。只需创建一个 'expandable group' 项目类型。然后在 getItemCount() 中计算所有项目及其嵌套项目（展开时）。看一下 Groupie 源代码。
对您的代码的一些额外反馈：
- 我会明确地将 header 添加到您提供给适配器的项目列表中。因此，您宁愿提供
List<Item> 而不是 List<Plants> 并具有 HeaderItem 和 PlantsItem。通过这种方式，您可以在适配器中明确区分领域模型 (Plants) 和视图模型（项目）。
- 您的
onBindViewHolder() 方法做得太多了。让你的 ViewHolder 子类来处理。使用抽象 bindTo(Item item) 方法创建抽象 ViewHolder。然后在您的 HeaderViewHolder 中对其进行子类化并执行实际工作（在 instanceof 检查之后）。
- 看看 view binding, it can make your code more concise. (So does Kotlin。）
您可以使用 ConcatAdapter to have multiple adapters with ViewHolders that hold different type of layouts even with the ones that contain RecyclerViews, i used in my last project and it works fine, you can check it out here，仪表板模块使用多个适配器来实现不同类型的布局。
你也可以使用他们在Google iosched app to have one adapter with multiple layouts in better way where you move logic from adapter to ViewHolders and their wrapper class ViewBinders. ViewBinder负责的方法
调用 onViewHolder、onCreateViewHolder 并将数据类型绑定到 ViewBinder 并将 ViewBinder 绑定到布局。有一篇关于如何在 medium 中使用它的文章，如果我能找到它，我会 post link。您还可以查看我为动画创建但使用 ViewBinders 以简单形式创建不同类型布局的示例。
以下是我希望在 GridLayout 中显示的数据类型和布局以及顺序
val data = mutableListOf<Any>().apply {
// Add Vector Drawables
add(HeaderModel("Animated Vector Drawable"))
add(AVDModel(R.drawable.avd_likes))
add(AVDModel(R.drawable.avd_settings))
add(HeaderModel("Seekable Vector Drawable"))
add(SeekableVDModel(R.drawable.avd_compass_rotation))
add(SeekableVDModel(R.drawable.avd_views))
add(SeekableVDModel(R.drawable.avd_hourglass))
add(HeaderModel("Clocks"))
add(AVDModel(R.drawable.avd_clock_alarm))
add(AVDModel(R.drawable.avd_clock_clock))
add(AVDModel(R.drawable.avd_clock_stopwatch))
}
这些是我想在我的 RecyclerView 中使用的对应数据类型，它是这些 类.
中与 ViewHolder 和布局的类型和绑定
private fun createViewBinders(): HashMap<ItemClazz, MappableItemBinder> {
val avdViewBinder = AVDViewBinder()
val seekableVDViewBinder = SeekableVDViewBinder()
val headViewBinder = HeaderViewBinder()
return HashMap<ItemClazz, MappableItemBinder>()
.apply {
put(
avdViewBinder.modelClazz,
avdViewBinder as MappableItemBinder
)
put(
seekableVDViewBinder.modelClazz,
seekableVDViewBinder as MappableItemBinder
)
put(
headViewBinder.modelClazz,
headViewBinder as MappableItemBinder
)
}
}
并将数据List设置为adapter，让adapter调用对应的绑定数据的layout
val dataList:List<Any> = getVectorDrawableItemList()
val recyclerView = findViewById<RecyclerView>(R.id.recyclerView)
val adapter = MultipleViewBinderListAdapter(
createViewBinders(),
RecyclerView.Adapter.StateRestorationPolicy.ALLOW
).apply {
submitList(dataList)
}
对于可扩展列表，iosched app 是一个很好的方法，在 RecyclerView here 中有关于如何为可扩展项目设置动画的视频。您可以在 ViewHolder 中设置状态，甚至可以使用 MotionLayout 设置从折叠状态到可展开状态的动画。所有这些都可以在没有任何第三方库和非常干净的方式下完成。
我正在设计一个比较复杂的UI，我搜索了Whosebug并没有找到类似的设计。可能有很多方法可以解决这个问题，但我想就如何实现这一点征求专家意见，我想分享我的方法并确保我以正确的方式进行。我的方法是，我使用 header 创建了一个回收视图，在 header 回收视图中，我正在使用由 h6ah4i (taken from github) 开发的可扩展回收视图库。如果有更好的方法，请告诉我。
下面的图片预览是我想要得到的最终结果的实时模型。这不是实际的屏幕。我的问题是实现此目标的最佳方法是什么，我应该在 recycleview header 中使用可扩展的 recycleview 还是可扩展的列表视图。我感谢任何答案，因为它不必与我的代码相似。欢迎任何建议。我希望这个 post 也能帮助像我一样的其他人寻找类似的解决方案。
RecycleView 适配器
public class RecycleAdapterPlantSearch extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static final int TYPE_HEADER = 0;
private static final int TYPE_ITEM = 1;
private List<Plants> plantsList;
private Context context;
private OnItemClickListener onItemClickListener;
public RecycleAdapterPlantSearch(Context context, List<Plants> plantsList, OnItemClickListener onClickListener) {
this.context = context;
this.plantsList = plantsList;
onItemClickListener = onClickListener;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == TYPE_ITEM) {
// Here Inflating your recyclerview item layout
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_view_plant_search_plant_item, parent, false);
return new ItemViewHolder(itemView, onItemClickListener);
} else if (viewType == TYPE_HEADER) {
// Here Inflating your header view
View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_view_plant_search_header, parent, false);
return new HeaderViewHolder(itemView, onItemClickListener);
} else return null;
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
/*
position 0 is for header
*/
if (holder instanceof HeaderViewHolder) {
// setheadersdata_flag = true;
HeaderViewHolder headerViewHolder = (HeaderViewHolder) holder;
// You have to set your header items values with the help of model class and you can modify as per your needs
// Setup expandable feature and RecyclerView
RecyclerViewExpandableItemManager expMgr = new RecyclerViewExpandableItemManager(null);
SimpleDemoExpandableItemAdapter.OnListItemClickMessageListener clickListener = message -> {
Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
};
List<BadgesVM> badgesVMList = null;
badgesVMList = new ArrayList() {{
add(new BadgesVM("447", "Bienenfreundlich", "bienenfreundlich", false));
add(new BadgesVM("320,322", "Vogelfreundlich", "vogelfreundlich", false));
add(new BadgesVM("321", "Insektenfreundlich", "insektenfreundlich", false));
add(new BadgesVM("445", "Ökologisch wertvoll", "oekologisch", false));
add(new BadgesVM("531", "Schmetterlings freundlich", "schmetterlings", false));
add(new BadgesVM("530", "Heimische Pflanze'", "heimische Pflanze'", false));
}};
// Create wrapped adapter: MyItemAdapter -> expMgr.createWrappedAdapter -> MyHeaderFooterAdapter
RecyclerView.Adapter adapter;
adapter = new SimpleDemoExpandableItemAdapter(context, expMgr,badgesVMList, clickListener);
adapter = expMgr.createWrappedAdapter(adapter);
//adapter = new DemoHeaderFooterAdapter(adapter, null);
headerViewHolder.recyclerViewExpandable.setAdapter(adapter);
headerViewHolder.recyclerViewExpandable.setLayoutManager(new LinearLayoutManager(context));
// NOTE: need to disable change animations to ripple effect work properly
((SimpleItemAnimator) headerViewHolder.recyclerViewExpandable.getItemAnimator()).setSupportsChangeAnimations(false);
expMgr.attachRecyclerView(headerViewHolder.recyclerViewExpandable);
} else if (holder instanceof ItemViewHolder) {
final ItemViewHolder itemViewHolder = (ItemViewHolder) holder;
itemViewHolder.plantDescText.setText(plantsList.get(position - 1).getDescription());
RequestOptions options = new RequestOptions()
.centerCrop()
.placeholder(R.drawable.background_small);
String imageUrl = APP_URL.BASE_ROUTE_INTERN + plantsList.get(position - 1).getImages().get(0).getSrcAttr();
Glide.with(context).load(imageUrl).apply(options).into(itemViewHolder.plantImg);
}
}
@Override
public int getItemViewType(int position) {
if (position == 0) {
return TYPE_HEADER;
}
return TYPE_ITEM;
}
@Override
public long getItemId(int position) {
return position;
}
// getItemCount increasing the position to 1. This will be the row of header
@Override
public int getItemCount() {
return plantsList.size() + 1;
}
public interface OnItemClickListener {
void OnItemClickListener(View view, int position);
void RecycleViewExtraDetails(ChipGroup chipGroup);
void nestedRecycleViewsSpecialOdd(RecyclerView nestedRecycleView);
}
private class HeaderViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private TextView searchNameTxt, searchFamilyTxt, plantGroupTxt, plantFamilySearchTxt, ecologyFilterTxt,
frostSearchTxt;
private ChipGroup chipGroup;
private Button filterSearchBtn;
private CardView ecologyCv;
private CardView detailSearchCv;
private RecyclerView recyclerViewExpandable;
public HeaderViewHolder(View headerView, OnItemClickListener onItemClickListener) {
super(headerView);
searchNameTxt = headerView.findViewById(R.id.textView_plant_search_header_plant_search);
searchFamilyTxt = headerView.findViewById(R.id.textView_plant_search_header_plant_search);
ecologyCv = headerView.findViewById(R.id.cardView_plant_search_header_ecology);
detailSearchCv = headerView.findViewById(R.id.cardView_plant_search_header_detail_search);
plantGroupTxt = headerView.findViewById(R.id.textView_plant_search_header_plant_group);
plantFamilySearchTxt = headerView.findViewById(R.id.textView_plant_search_header_plant_family);
ecologyFilterTxt = headerView.findViewById(R.id.textView_plant_search_header_ecology_filter);
frostSearchTxt = headerView.findViewById(R.id.textView_plant_search_header_frost_filter);
chipGroup = headerView.findViewById(R.id.chip_group_plant_search_header);
filterSearchBtn = headerView.findViewById(R.id.button_plant_search_header_filter_search);
recyclerViewExpandable = headerView.findViewById(R.id.expandable_list_view_plant_search);
searchNameTxt.setOnClickListener(this);
searchFamilyTxt.setOnClickListener(this);
ecologyCv.setOnClickListener(this);
detailSearchCv.setOnClickListener(this);
plantGroupTxt.setOnClickListener(this);
plantFamilySearchTxt.setOnClickListener(this);
ecologyFilterTxt.setOnClickListener(this);
filterSearchBtn.setOnClickListener(this);
frostSearchTxt.setOnClickListener(this);
}
@Override
public void onClick(View view) {
onItemClickListener.OnItemClickListener(view, getAdapterPosition());
onItemClickListener.RecycleViewExtraDetails(chipGroup);
}
}
public class ItemViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private Button readMoreBtn;
private TextView plantDescText;
private ImageView plantImg;
public ItemViewHolder(View itemView, OnItemClickListener onItemClickListener) {
super(itemView);
plantDescText = itemView.findViewById(R.id.textView_plant_search_plants_item_description_text);
readMoreBtn = itemView.findViewById(R.id.button_plant_search_plant_item_read_more);
plantImg = itemView.findViewById(R.id.imageView_plant_search_plants_item_plant_image);
readMoreBtn.setOnClickListener(this);
}
@Override
public void onClick(View view) {
onItemClickListener.OnItemClickListener(view, getAdapterPosition() - 1);
}
}
}
嵌套header回收视图
public class SimpleDemoExpandableItemAdapter extends AbstractExpandableItemAdapter<SimpleDemoExpandableItemAdapter.MyGroupViewHolder,
SimpleDemoExpandableItemAdapter.MyChildViewHolder> implements View.OnClickListener {
RecyclerViewExpandableItemManager mExpandableItemManager;
List<MyBaseItem> mItems;
OnListItemClickMessageListener mOnItemClickListener;
List<BadgesVM> badgesVMList;
Context context;
static class MyBaseItem {
public final int id;
public final String text;
public MyBaseItem(int id, String text) {
this.id = id;
this.text = text;
}
}
static abstract class MyBaseViewHolder extends AbstractExpandableItemViewHolder {
TextView textView;
Slider frostSlider;
RecyclerView detailRecycleView;
public MyBaseViewHolder(View itemView) {
super(itemView);
textView = itemView.findViewById(android.R.id.text1);
frostSlider = itemView.findViewById(R.id.slider_plant_search_expandable);
detailRecycleView = itemView.findViewById(R.id.recycle_view_plant_search_detail_search);
}
}
static class MyGroupViewHolder extends MyBaseViewHolder {
public MyGroupViewHolder(View itemView) {
super(itemView);
}
}
static class MyChildViewHolder extends MyBaseViewHolder {
public MyChildViewHolder(View itemView) {
super(itemView);
}
}
public SimpleDemoExpandableItemAdapter(Context context, RecyclerViewExpandableItemManager expMgr, List<BadgesVM> badgesVMList, OnListItemClickMessageListener clickListener) {
mExpandableItemManager = expMgr;
mOnItemClickListener = clickListener;
this.badgesVMList = badgesVMList;
this.context = context;
setHasStableIds(true); // this is required for expandable feature.
mItems = new ArrayList<>();
mItems.add(new MyBaseItem(0, "Filter nach ökologischen Kriterien"));
mItems.add(new MyBaseItem(1, "Frosthärte"));
mItems.add(new MyBaseItem(2, "Detailsuche"));
}
@Override
public int getGroupCount() {
return mItems.size();
}
@Override
public int getChildCount(int groupPosition) {
int childCount = 0;
int groupId = mItems.get(groupPosition).id;
if (groupId == 0) {
childCount = badgesVMList.size();
} else if (groupId == 1) {
childCount = 1; //contains only one item
} else if (groupId == 2) {
childCount = 1; //contains only one item
}
return childCount;
}
@Override
public long getGroupId(int groupPosition) {
// This method need to return unique value within all group items.
return mItems.get(groupPosition).id;
}
@Override
public long getChildId(int groupPosition, int childPosition) {
// This method need to return unique value within the group.
int groupId = mItems.get(groupPosition).id;
int childId = 0;
if (groupId == 0) {
badgesVMList.get(childPosition).getId();
} else if (groupId == 1) {
childId = 0;
} else if (groupId == 2) {
childId = 0;
}
return childId;
}
@Override
@NonNull
public MyGroupViewHolder onCreateGroupViewHolder(@NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_group_item_for_expandable_minimal, parent, false);
MyGroupViewHolder vh = new MyGroupViewHolder(v);
vh.itemView.setOnClickListener(this);
return vh;
}
@Override
@NonNull
public MyChildViewHolder onCreateChildViewHolder(@NonNull ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_child_item_for_expandable_minimal, parent, false);
MyChildViewHolder vh = new MyChildViewHolder(v);
vh.itemView.setOnClickListener(this);
return vh;
}
@Override
public void onBindGroupViewHolder(@NonNull MyGroupViewHolder holder, int groupPosition, int viewType) {
MyBaseItem group = mItems.get(groupPosition);
holder.textView.setText(group.text);
}
@Override
public void onBindChildViewHolder(@NonNull MyChildViewHolder holder, int groupPosition, int childPosition, int viewType) {
int groupId = mItems.get(groupPosition).id;
if (groupId == 0) {
BadgesVM badgesVM = badgesVMList.get(childPosition);
holder.textView.setVisibility(View.VISIBLE);
holder.frostSlider.setVisibility(View.GONE);
holder.detailRecycleView.setVisibility(View.GONE);
holder.textView.setText(badgesVM.getName());
} else if (groupId == 1) {
holder.textView.setVisibility(View.GONE);
holder.frostSlider.setVisibility(View.VISIBLE);
holder.detailRecycleView.setVisibility(View.GONE);
} else if (groupId == 2) {
holder.textView.setVisibility(View.GONE);
holder.frostSlider.setVisibility(View.GONE);
holder.detailRecycleView.setVisibility(View.VISIBLE);
// Setup expandable feature and RecyclerView
RecyclerViewExpandableItemManager expMgr = new RecyclerViewExpandableItemManager(null);
DetailSearchExpandableItemAdapter.OnListItemClickMessageListener clickListener = message -> {
Toast.makeText(context, message, Toast.LENGTH_SHORT).show();
};
List<BadgesVM> badgesVMList = null;
badgesVMList = new ArrayList() {{
add(new BadgesVM("447", "Bienenfreundlich", "bienenfreundlich", false));
add(new BadgesVM("320,322", "Vogelfreundlich", "vogelfreundlich", false));
add(new BadgesVM("321", "Insektenfreundlich", "insektenfreundlich", false));
add(new BadgesVM("445", "Ökologisch wertvoll", "oekologisch", false));
add(new BadgesVM("531", "Schmetterlings freundlich", "schmetterlings", false));
add(new BadgesVM("530", "Heimische Pflanze'", "heimische Pflanze'", false));
}};
// Create wrapped adapter: MyItemAdapter -> expMgr.createWrappedAdapter -> MyHeaderFooterAdapter
RecyclerView.Adapter adapter2;
adapter2 = new DetailSearchExpandableItemAdapter(context, expMgr, badgesVMList, clickListener);
adapter2 = expMgr.createWrappedAdapter(adapter2);
//adapter = new DemoHeaderFooterAdapter(adapter, null);
holder.detailRecycleView.setAdapter(adapter2);
holder.detailRecycleView.setLayoutManager(new LinearLayoutManager(context));
// NOTE: need to disable change animations to ripple effect work properly
((SimpleItemAnimator) holder.detailRecycleView.getItemAnimator()).setSupportsChangeAnimations(false);
expMgr.attachRecyclerView(holder.detailRecycleView);
}
}
@Override
public boolean onCheckCanExpandOrCollapseGroup(@NonNull MyGroupViewHolder holder, int groupPosition, int x, int y, boolean expand) {
// handles click event manually (to show Snackbar message)
return false;
}
@Override
public void onClick(View v) {
RecyclerView rv = RecyclerViewAdapterUtils.getParentRecyclerView(v);
RecyclerView.ViewHolder vh = rv.findContainingViewHolder(v);
int rootPosition = vh.getAdapterPosition();
if (rootPosition == RecyclerView.NO_POSITION) {
return;
}
// need to determine adapter local flat position like this:
RecyclerView.Adapter rootAdapter = rv.getAdapter();
int localFlatPosition = WrapperAdapterUtils.unwrapPosition(rootAdapter, this, rootPosition);
long expandablePosition = mExpandableItemManager.getExpandablePosition(localFlatPosition);
int groupPosition = RecyclerViewExpandableItemManager.getPackedPositionGroup(expandablePosition);
int childPosition = RecyclerViewExpandableItemManager.getPackedPositionChild(expandablePosition);
String message;
if (childPosition == RecyclerView.NO_POSITION) {
// Clicked item is a group!
// toggle expand/collapse
if (mExpandableItemManager.isGroupExpanded(groupPosition)) {
mExpandableItemManager.collapseGroup(groupPosition);
message = "COLLAPSE: Group " + groupPosition;
} else {
mExpandableItemManager.expandGroup(groupPosition);
message = "EXPAND: Group " + groupPosition;
}
} else {
// Clicked item is a child!
message = "CLICKED: Child " + groupPosition + "-" + childPosition;
}
mOnItemClickListener.onItemClicked(message);
}
public interface OnListItemClickMessageListener {
void onItemClicked(String message);
}
}
您搜索为您完成大部分工作的图书馆是正确的，但我不喜欢您选择的图书馆。它看起来不是很灵活和简洁。我建议查看 Groupie, its API is pretty clean. Also check Reddit 以了解有关库的一些讨论。
如果你想自己写，我想你可以不用嵌套 Adapter 来解决它。只需创建一个 'expandable group' 项目类型。然后在 getItemCount() 中计算所有项目及其嵌套项目（展开时）。看一下 Groupie 源代码。
对您的代码的一些额外反馈：
- 我会明确地将 header 添加到您提供给适配器的项目列表中。因此，您宁愿提供
List<Item>而不是List<Plants>并具有HeaderItem和PlantsItem。通过这种方式，您可以在适配器中明确区分领域模型 (Plants) 和视图模型（项目）。 - 您的
onBindViewHolder()方法做得太多了。让你的ViewHolder子类来处理。使用抽象bindTo(Item item)方法创建抽象ViewHolder。然后在您的HeaderViewHolder中对其进行子类化并执行实际工作（在 instanceof 检查之后）。 - 看看 view binding, it can make your code more concise. (So does Kotlin。）
您可以使用 ConcatAdapter to have multiple adapters with ViewHolders that hold different type of layouts even with the ones that contain RecyclerViews, i used in my last project and it works fine, you can check it out here，仪表板模块使用多个适配器来实现不同类型的布局。
你也可以使用他们在Google iosched app to have one adapter with multiple layouts in better way where you move logic from adapter to ViewHolders and their wrapper class ViewBinders. ViewBinder负责的方法 调用 onViewHolder、onCreateViewHolder 并将数据类型绑定到 ViewBinder 并将 ViewBinder 绑定到布局。有一篇关于如何在 medium 中使用它的文章，如果我能找到它，我会 post link。您还可以查看我为动画创建但使用 ViewBinders 以简单形式创建不同类型布局的示例。
以下是我希望在 GridLayout 中显示的数据类型和布局以及顺序
val data = mutableListOf<Any>().apply {
// Add Vector Drawables
add(HeaderModel("Animated Vector Drawable"))
add(AVDModel(R.drawable.avd_likes))
add(AVDModel(R.drawable.avd_settings))
add(HeaderModel("Seekable Vector Drawable"))
add(SeekableVDModel(R.drawable.avd_compass_rotation))
add(SeekableVDModel(R.drawable.avd_views))
add(SeekableVDModel(R.drawable.avd_hourglass))
add(HeaderModel("Clocks"))
add(AVDModel(R.drawable.avd_clock_alarm))
add(AVDModel(R.drawable.avd_clock_clock))
add(AVDModel(R.drawable.avd_clock_stopwatch))
}
这些是我想在我的 RecyclerView 中使用的对应数据类型，它是这些 类.
中与 ViewHolder 和布局的类型和绑定private fun createViewBinders(): HashMap<ItemClazz, MappableItemBinder> {
val avdViewBinder = AVDViewBinder()
val seekableVDViewBinder = SeekableVDViewBinder()
val headViewBinder = HeaderViewBinder()
return HashMap<ItemClazz, MappableItemBinder>()
.apply {
put(
avdViewBinder.modelClazz,
avdViewBinder as MappableItemBinder
)
put(
seekableVDViewBinder.modelClazz,
seekableVDViewBinder as MappableItemBinder
)
put(
headViewBinder.modelClazz,
headViewBinder as MappableItemBinder
)
}
}
并将数据List设置为adapter，让adapter调用对应的绑定数据的layout
val dataList:List<Any> = getVectorDrawableItemList()
val recyclerView = findViewById<RecyclerView>(R.id.recyclerView)
val adapter = MultipleViewBinderListAdapter(
createViewBinders(),
RecyclerView.Adapter.StateRestorationPolicy.ALLOW
).apply {
submitList(dataList)
}
对于可扩展列表，iosched app 是一个很好的方法，在 RecyclerView here 中有关于如何为可扩展项目设置动画的视频。您可以在 ViewHolder 中设置状态，甚至可以使用 MotionLayout 设置从折叠状态到可展开状态的动画。所有这些都可以在没有任何第三方库和非常干净的方式下完成。