本文介绍了RecyclerView onBindViewHolder仅在getItemViewType更改时调用的处理方法,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
我有一个具有多种视图类型的视图支架.
I have a viewholder with multiple viewtypes.
滚动onBindViewHolder
时,仅当getItemViewType
更改值时才调用.这会导致我的列表项无法正确更新.
When scrolling onBindViewHolder
is only called when getItemViewType
changes value. This causes my list items to not be updated properly.
这是一个错误吗?还是我在这里做错了.从新的recyclerView
类看来,这是非常奇怪的行为.
Is this a bug? Or I'm i doing something wrong here. This seems very strange behaviour from the new recyclerView
class.
这是我的适配器:
package se.davison.smartrecycleradapter;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.util.SparseIntArray;
import android.view.LayoutInflater;
import android.view.ViewGroup;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
/**
* Created by richard on 10/11/14.
*/
public class SectionAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static final String TAG = SectionAdapter.class.getSimpleName();
private final LayoutInflater inflater;
private final int sectionLayoutId;
private SparseIntArray positionSection;
private LinkedHashMap<AdapterItem, List<AdapterItem>> items = new LinkedHashMap<AdapterItem, List<AdapterItem>>();
private List<Class<? extends AdapterItem>> itemTypes = new ArrayList<Class<? extends AdapterItem>>(20);
public SectionAdapter(Context context, int sectionLayoutId, LinkedHashMap<AdapterItem, List<AdapterItem>> items) {
this.inflater = LayoutInflater.from(context);
this.sectionLayoutId = sectionLayoutId;
this.items = items;
initList(items);
}
public SectionAdapter(Context context, int sectionLayoutId) {
this.inflater = LayoutInflater.from(context);
this.sectionLayoutId = sectionLayoutId;
this.items = new LinkedHashMap<AdapterItem, List<AdapterItem>>();
initList(items);
}
@Override
public int getItemViewType(int position) {
AdapterItem item = getItem(position);
Log.d(TAG, position + ": class " + item.getClass());
return itemTypes.indexOf(item.getClass());
}
@Override
public int getItemCount() {
int count = 0;
if (items == null) {
return 0;
}
for (AdapterItem key : items.keySet()) {
count++;
List<AdapterItem> childItems = items.get(key);
if (childItems != null) {
count += childItems.size();
}
}
return count;
}
private void initList(HashMap<AdapterItem, List<AdapterItem>> items) {
positionSection = new SparseIntArray(items.size());
int count = 0;
int sectionIndex = -1;
for (AdapterItem key : items.keySet()) {
Class headerClass = key.getClass();
if (!itemTypes.contains(headerClass)) {
itemTypes.add(headerClass);
}
List<AdapterItem> childItems = items.get(key);
sectionIndex = count;
if (childItems != null) {
for (AdapterItem item : childItems) {
Class clazz = item.getClass();
if (!itemTypes.contains(clazz)) {
itemTypes.add(clazz);
}
positionSection.put(count, sectionIndex);
count++;
}
}
count++;
}
setHasStableIds(true);
}
private AdapterItem getItem(int position) {
int totalChildCount = 0;
int separatorCount = 0;
for (AdapterItem key : items.keySet()) {
if (position == 0 || position == totalChildCount + separatorCount) {
return key;
}
separatorCount++;
List<AdapterItem> list = items.get(key);
int couldCount = countList(list);
if (position < totalChildCount + separatorCount + couldCount) {
return list.get(position - (totalChildCount + separatorCount));
}
totalChildCount += couldCount;
}
return null;
}
public void setItems(LinkedHashMap<AdapterItem, List<AdapterItem>> items) {
this.items = items;
notifyDataSetChanged();
}
public void setItemsAtHeader(int id, List<AdapterItem> items) {
AdapterItem header = null;
for (AdapterItem key : this.items.keySet()) {
if (key.headerId() == id) {
header = key;
break;
}
}
if (header == null) {
throw new IllegalArgumentException(String.format("No header with id %s is found", id));
}
setItemsAtHeader(header, items);
}
private void setItemsAtHeader(AdapterItem header, List<AdapterItem> items) {
this.items.put(header, items);
}
private int countList(List<?> list) {
return list == null ? 0 : list.size();
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
AdapterItem firstItem = getFirstItemWithClass(itemTypes.get(viewType));
return firstItem.onCreateViewHolder(inflater, viewGroup);
}
private AdapterItem getFirstItemWithClass(Class<? extends AdapterItem> clazz) {
for (AdapterItem key : items.keySet()) {
if (key.getClass() == clazz) {
return key;
}
List<AdapterItem> childItems = items.get(key);
if (childItems != null) {
for (AdapterItem item : childItems) {
if (item.getClass() == clazz) {
return item;
}
}
}
}
throw new IllegalStateException("Something is wrong, you dont have any items with that class in your list");
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {
AdapterItem item = getItem(position);
Log.d(TAG, "ITEM = " + item.getClass().getSimpleName());
Log.d(TAG, "POS = " + position);
if (item instanceof OneLineAdapterItem) {
Log.d(TAG, "TEXT = " + ((OneLineAdapterItem) item).getText());
}
item.onBindViewHolder(viewHolder, position);
}
}
我也像这样抽象出了这些项目:
I've also abstracted out the items like so:
public abstract class AdapterItem<VH extends RecyclerView.ViewHolder> {
public boolean isHeader(){
return false;
}
public int headerId(){
return -1;
}
public abstract VH onCreateViewHolder(LayoutInflater inflater, ViewGroup parent);
public abstract void onBindViewHolder(VH viewHolder, int position);
}
还有部分
public class SectionAdapterItem extends AdapterItem<SectionAdapterItem.ViewHolder> {
private String text;
private boolean dividerVisible = false;
public static class ViewHolder extends RecyclerView.ViewHolder{
TextView titel;
ImageView divider;
public ViewHolder(View itemView) {
super(itemView);
titel = (TextView) itemView.findViewById(android.R.id.title);
divider = (ImageView) itemView.findViewById(android.R.id.icon);
}
}
public void setDividerVisible(boolean dividerVisible) {
this.dividerVisible = dividerVisible;
}
public boolean isDividerVisible() {
return dividerVisible;
}
@Override
public boolean isHeader() {
return true;
}
@Override
public int headerId() {
return super.headerId();
}
public SectionAdapterItem(String text) {
this.text = text;
}
@Override
public ViewHolder onCreateViewHolder(LayoutInflater inflater, ViewGroup parent) {
return new ViewHolder(inflater.inflate(R.layout.top_header, parent, false));
}
@Override
public void onBindViewHolder(ViewHolder viewHolder, int position) {
viewHolder.titel.setText(text);
viewHolder.divider.setVisibility(dividerVisible?View.VISIBLE:View.GONE);
}
}
对于第一个可见行它工作正常,但随后失败.
It works fine for the frist visible rows, but then it fails.
推荐答案
使用setHasStableIds(true);
实施即可解决问题!
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