这是我的第一个堆栈溢出问题。在过去的几个小时里，我一直试图找到解决堆栈溢出问题的方法，但我找不到任何东西。
我在这里创建的app（或特定活动）非常简单，基本上是一个包含TextView和RecyclerView的垂直回收器，类似于：
Vertical RecyclerView
--- TextView（标题）
---水平RecyclerView（卡片视图）
--- TextView（标题）
---水平RecyclerView（卡片视图）
......（更多内容）
--- TextView（标题）
---水平RecyclerView（卡片视图）
（垂直RecyclerView结束）
一切正常，除非我开始滚动垂直回收器（向上和向下），第一个和最后两个水平的RecyclerView的空间项目装饰（如下所示）不断增加。我猜我的问题可能在哪里，但我不知道如何解决它。
卧式循环器适配器（非常标准）
public class HorizontalRecyclerViewAdapter extends RecyclerView.Adapter<HorizontalRecyclerViewAdapter.ViewHolder> {
private ArrayList<String> mDataset;
private Context mContext;
// Provide a reference to the views for each data item
// Complex data items may need more than one view per item, and
// you provide access to all the views for a data item in a view holder
public class ViewHolder extends RecyclerView.ViewHolder {
// each data item is just a string in this case
public TextView txtViewTitle;
public ImageView imgViewIcon;
public ViewHolder(View itemLayoutView) {
super(itemLayoutView);
txtViewTitle = (TextView) itemLayoutView.findViewById(R.id.text_view);
imgViewIcon = (ImageView) itemLayoutView.findViewById(R.id.image_view);
}
}
// Provide a suitable constructor (depends on the kind of mDataset)
public HorizontalRecyclerViewAdapter(Context myContext, ArrayList myDataset) {
this.mContext = myContext;
this.mDataset = myDataset;
}
// Create new views (invoked by the layout manager)
@Override
public HorizontalRecyclerViewAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
// create a new view
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.view_image, parent, false);
// Goes here: set the view's size, margins, paddings and layout parameters
ViewHolder viewHolder = new ViewHolder(v);
return viewHolder;
}
// Replace the contents of a view (invoked by the layout manager)
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
// - get element from your mDataset at this position
// - replace the contents of the view with that element
String mDrawableName = mDataset.get(position);
int resID = mContext.getResources().getIdentifier(mDrawableName , "drawable", mContext.getPackageName());
holder.imgViewIcon.setImageResource(resID);
}
// Return the size of your mDataset (invoked by the layout manager)
@Override
public int getItemCount() {
return mDataset.size();
}
空间物品装饰
class HorizantalSpaceItemDecoration extends RecyclerView.ItemDecoration {
private final int mHorizantalSpaceWidth;
public HorizantalSpaceItemDecoration(int horizantalItemSpace) {
mHorizantalSpaceWidth = horizantalItemSpace;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
RecyclerView.State state) {
outRect.right = mHorizantalSpaceWidth;
}
Vertical Recycler Adapter：
public class VerticalRecyclerViewAdapter extends RecyclerView.Adapter<VerticalRecyclerViewAdapter.ViewHolder> {
private ArrayList<String> mHeaderList;
private ArrayList<String> mSportList;
private ArrayList<Boolean> mSpaceItemDecorationFlagList;
private Context context;
public static final int HORIZANTAL_ITEM_SPACE = 30;
// Provide a reference to the views for each data item
// Complex data items may need more than one view per item, and
// you provide access to all the views for a data item in a view holder
public class ViewHolder extends RecyclerView.ViewHolder {
// each data item is just a string in this case
public TextView textView;
public CardView cardView;
public RecyclerView recyclerView;
public ViewHolder(View itemLayoutView) {
super(itemLayoutView);
cardView = (CardView) itemLayoutView.findViewById(R.id.card_view);
textView = (TextView) itemLayoutView.findViewById(R.id.text_view);
recyclerView = (RecyclerView) itemLayoutView.findViewById(R.id.recycler_view);
}
}
// Provide a suitable constructor (depends on the kind of mHeaderList)
public VerticalRecyclerViewAdapter(Context context) {
Resources res = context.getResources();
String[] headers = res.getStringArray(R.array.header_home);
mHeaderList = new ArrayList<String>(Arrays.asList(headers));
String[] sports = res.getStringArray(R.array.sports);
mSportList = new ArrayList<String>(Arrays.asList(sports));
mSpaceItemDecorationFlagList = new ArrayList<Boolean>();
for(int i = 0; i < mHeaderList.size(); i++){
mSpaceItemDecorationFlagList.add(false);
}
this.context = context;
}
@Override
public int getItemViewType(int position) {
// Just as an example, return 0 or 2 depending on position
// Note that unlike in ListView adapters, types don't have to be contiguous
return position % 2 * 2;
}
// Create new views (invoked by the layout manager)
@Override
public VerticalRecyclerViewAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
// Create a new view depends on view type
// 0: Text View (Header)
// 1: Recycler View (Category Explorer)
View newView;
if(viewType == 0) {
newView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.view_text, parent, false);
}else{
newView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.view_recycler, parent, false);
}
// Goes here: set the view's size, margins, paddings and layout parameters
ViewHolder viewHolder = new ViewHolder(newView);
return viewHolder;
}
// Replace the contents of a view (invoked by the layout manager)
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
// - get element from your mHeaderList at this position
// - replace the contents of the view with that element
if(position % 2 == 0)
{
String header = mHeaderList.get(position);
holder.textView.setText(header);
}else{
// ??????????????
// Problem might be holder.recyclerView not reset properly?
RecyclerView.LayoutManager popularLayoutManager= new LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false);
RecyclerView.Adapter adapter = new HorizontalRecyclerViewAdapter(context, mSportList);
holder.recyclerView.setLayoutManager(popularLayoutManager);
holder.recyclerView.setAdapter(adapter);
//add Space ItemDecoration
holder.recyclerView.addItemDecoration(new HorizantalSpaceItemDecoration(HORIZANTAL_ITEM_SPACE));
holder.recyclerView.setHasFixedSize(true);
}
}
// Return the size of your mHeaderList (invoked by the layout manager)
@Override
public int getItemCount() {
return mHeaderList.size();
}
在每个水平回收器中，我试图在每个图像/项目之间添加30 dp空间，但在滚动期间，第一个水平和最后两个水平回收器视图不断增加。 （30，然后60，然后90我猜？）
我的猜测是在onBindViewHolder（）中，我的持有者的回收者视图未正确重置，并且其rect.right不断更新为新值（旧+30）。但这纯粹是我的猜测。还有其他人可以吗？
提前致谢。
答案 0 :(得分：2)
这里的问题是项目装饰器被添加每次数据被绑定到视图持有者。虽然之前添加的那些永远不会被删除。
可以进行检查以防止这种情况发生，或者我们可以删除现有的检查。但最好只声明和添加装饰器一次，即创建视图时。
所以要解决这个问题：
课程VerticalRecyclerViewAdapter：
目前，您正在onBindViewHolder方法中添加项目修饰。每次持有者被重新渲染时都会被调用（在滚动时发生），因此我们需要将其从此处删除。
然后转到onCreateViewHolder方法并将装饰添加到那里的视图。
请注意，您需要检查您的情况是否为viewType == 1，否则会导致NullPointer。
因此，您生成的onCreateViewHolder方法可能如下所示：
// Create new views (invoked by the layout manager)
@Override
public VerticalRecyclerViewAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
// Create a new view depends on view type
// 0: Text View (Header)
// 1: Recycler View (Category Explorer)
View newView;
if (viewType == 0) {
newView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.view_text, parent, false);
} else {
newView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.view_recycler, parent, false);
}
// Goes here: set the view's size, margins, paddings and layout parameters
ViewHolder viewHolder = new ViewHolder(newView);
if (viewType == 1) {
// Adding the itemDecorator here
viewHolder.recyclerView.addItemDecoration(new HorizantalSpaceItemDecoration(HORIZANTAL_ITEM_SPACE));
}
return viewHolder;
}
答案 1 :(得分：1)
对于那些正面临这个问题的人来说，这可能是因为每次数据更新时都会添加项目装饰视图（这很糟糕）。但是，作为快速解决方案，您可以检查“回收者”视图中是否添加了任何项目装饰器，如果没有，则可以添加您的装饰器。将此添加到您初始化适配器的活动或片段文件中
if (your_recycler_view.itemDecorationCount < 1) {
your_recycler_view.addItemDecoration(HorizantalSpaceItemDecoration())
}