RecyclerView 一次为所有项目调用 onCreateViewHolder 和 onBindViewHolder
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【中文标题】RecyclerView 一次为所有项目调用 onCreateViewHolder 和 onBindViewHolder【英文标题】：RecyclerView calling onCreateViewHolder and onBindViewHolder for all items at once 【发布时间】：2017-03-05 12:00:12 【问题描述】：我有一个 recyclerView 能够在屏幕上显示最多 3 个项目，但它同时为列表中的所有 45 个项目调用 onCreateViewHolder 和 onBindViewHolder（如下面的 LOG 中所示）。
难道不应该只在我将这些项目滚动到屏幕时才调用这些方法吗？
*我正在使用一个包含 0 和 1 的列表作为测试来定义它应该使用哪种布局。
我的适配器代码
public class MyRecyclerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>
int[] post_list;
private static final int TYPE_0 =0;
private static final int TYPE_1=1;
private LayoutInflater inflater;
private Context context;
Activity mActivity;
public MyRecyclerAdapter(Context context, int[] list, Activity mActivity)
this.context=context;
inflater=LayoutInflater.from(context);
this.list=list;
this.mActivity = mActivity;
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
Log.e("onCreateViewHolder", "CALLED");
if(viewType== TYPE_0)
View view=inflater.inflate(R.layout.layout_type0, parent,false);
Type0Holder holder=new Type0Holder(view);
return holder;
else
View view=inflater.inflate(R.layout.layout_type1, parent,false);
Type1Holder holder=new Type1Holder (view);
return holder;
@Override
public int getItemViewType(int position)
if(list[position]==0)
return TYPE_0;
else
return TYPE_1;
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position)
if(holder instanceof Type0Holder)
Type0Holder type0Holder = (Type0Holder) holder;
type0Holder .mTextView.setText("Layout type 0");
Glide.with(mActivity.getApplicationContext()).load(R.drawable.imageTest).into(type0Holder.mImageView);
else
Type1Holder type1Holder = (Type1Holder ) holder;
type1Holder .mTextView.setText("Layout type 1");
Glide.with(mActivity.getApplicationContext()).load(R.drawable.imageTest).into(type1Holder.mImageView);
Log.e("onBindViewHolder", String.valueOf(position));
@Override
public int getItemCount()
return post_list.length;
class Type0Holder extends RecyclerView.ViewHolder
TextView mTextView;
ImageView mImageView;
public Type0Holder (View view)
super(view);
mTextView= (TextView) itemView.findViewById(R.id.text_view0);
mImageView= (ImageView) itemView.findViewById(R.id.image_view0);
class Type1Holder extends RecyclerView.ViewHolder
TextView mTextView;
ImageView mImageView;
public ImagePostHolder(View itemView)
super(itemView);
mTextView= (TextView) itemView.findViewById(R.id.text_view1);
mImageView= (ImageView) itemView.findViewById(R.id.image_view1);
我的回收站 xml
<android.support.v4.widget.NestedScrollView
android:id="@+id/nested_scroll_view"
android:layout_
android:layout_
app:layout_behavior="@string/appbar_scrolling_view_behavior"
android:fillViewport="true"
android:paddingBottom="3dp"
>
<RelativeLayout
android:layout_
android:layout_
app:layout_behavior="@string/appbar_scrolling_view_behavior"
android:orientation="vertical"
android:clipToPadding="false">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler"
android:layout_
android:layout_
></android.support.v7.widget.RecyclerView>
</RelativeLayout>
</android.support.v4.widget.NestedScrollView>
我的 LOG 显示它正在一次调用所有项目，即使是那些不可见的项目。
10-23 15:15:46.093 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.113 28766-28766/com.example..E/HOLDER: 0
10-23 15:15:46.113 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.113 28766-28766/com.example..E/HOLDER: 1
10-23 15:15:46.113 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.123 28766-28766/com.example..E/HOLDER: 2
10-23 15:15:46.123 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.123 28766-28766/com.example..E/HOLDER: 3
10-23 15:15:46.123 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.133 28766-28766/com.example..E/HOLDER: 4
10-23 15:15:46.133 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.133 28766-28766/com.example..E/HOLDER: 5
10-23 15:15:46.143 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.143 28766-28766/com.example..E/HOLDER: 6
10-23 15:15:46.143 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.143 28766-28766/com.example..E/HOLDER: 7
10-23 15:15:46.153 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.153 28766-28766/com.example..E/HOLDER: 8
10-23 15:15:46.153 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.153 28766-28766/com.example..E/HOLDER: 9
10-23 15:15:46.163 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.163 28766-28766/com.example..E/HOLDER: 10
10-23 15:15:46.163 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.163 28766-28766/com.example..E/HOLDER: 11
10-23 15:15:46.173 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.173 28766-28766/com.example..E/HOLDER: 12
10-23 15:15:46.173 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.183 28766-28766/com.example..E/HOLDER: 13
10-23 15:15:46.183 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.183 28766-28766/com.example..E/HOLDER: 14
10-23 15:15:46.183 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.183 28766-28766/com.example..E/HOLDER: 15
10-23 15:15:46.193 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.193 28766-28766/com.example..E/HOLDER: 16
10-23 15:15:46.193 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.193 28766-28766/com.example..E/HOLDER: 17
10-23 15:15:46.203 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.203 28766-28766/com.example..E/HOLDER: 18
10-23 15:15:46.203 28766-28766/com.example..E/CREATE HOLDER: CALLED
10-23 15:15:46.213 28766-28766/com.example.. E/HOLDER: 19
10-23 15:15:46.213 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.213 28766-28766/com.example.. E/HOLDER: 20
10-23 15:15:46.213 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.213 28766-28766/com.example.. E/HOLDER: 21
10-23 15:15:46.223 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.223 28766-28766/com.example.. E/HOLDER: 22
10-23 15:15:46.223 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.233 28766-28766/com.example.. E/HOLDER: 23
10-23 15:15:46.233 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.233 28766-28766/com.example.. E/HOLDER: 24
10-23 15:15:46.233 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.233 28766-28766/com.example.. E/HOLDER: 25
10-23 15:15:46.243 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.243 28766-28766/com.example.. E/HOLDER: 26
10-23 15:15:46.243 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.243 28766-28766/com.example.. E/HOLDER: 27
10-23 15:15:46.253 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.253 28766-28766/com.example.. E/HOLDER: 28
10-23 15:15:46.253 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.253 28766-28766/com.example.. E/HOLDER: 29
10-23 15:15:46.263 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.263 28766-28766/com.example.. E/HOLDER: 30
10-23 15:15:46.263 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.263 28766-28766/com.example.. E/HOLDER: 31
10-23 15:15:46.273 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.283 28766-28766/com.example.. E/HOLDER: 32
10-23 15:15:46.283 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.283 28766-28766/com.example.. E/HOLDER: 33
10-23 15:15:46.293 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.313 28766-28766/com.example.. E/HOLDER: 34
10-23 15:15:46.313 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.323 28766-28766/com.example.. E/HOLDER: 35
10-23 15:15:46.323 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.323 28766-28766/com.example.. E/HOLDER: 36
10-23 15:15:46.333 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.333 28766-28766/com.example.. E/HOLDER: 37
10-23 15:15:46.333 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.343 28766-28766/com.example.. E/HOLDER: 38
10-23 15:15:46.343 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.343 28766-28766/com.example.. E/HOLDER: 39
10-23 15:15:46.343 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.353 28766-28766/com.example.. E/HOLDER: 40
10-23 15:15:46.353 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.353 28766-28766/com.example.. E/HOLDER: 41
10-23 15:15:46.353 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.363 28766-28766/com.example.. E/HOLDER: 42
10-23 15:15:46.363 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.363 28766-28766/com.example.. E/HOLDER: 43
10-23 15:15:46.373 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.373 28766-28766/com.example.. E/HOLDER: 44
10-23 15:15:46.373 28766-28766/com.example.. E/CREATE HOLDER: CALLED
10-23 15:15:46.383 28766-28766/com.example.. E/HOLDER: 45
更新 1 - 我发现我的 recyclerView 不回收的原因是因为它在 NestedScrowView 内，那么即使它在 NestedScrowView 内，我如何让它回收视图？
【问题讨论】：
您找到解决方案了吗？ @PedroMazarini 你找到解决方案了吗？ @Midhilaj 我实际上不记得我是如何解决这个问题的，已经有一段时间了。无论如何，我一直在使用 Android，如果有什么可以帮助您的，请告诉我。 【参考方案1】：我遇到了同样的问题。在我的情况下，NestedScrollView 是 Bottom Sheet 的根，我将其替换为 FrameLayout，并且它起作用了。
如果可以，您应该尝试使用FrameLayout
【讨论】：
在我的情况下，我需要使用 NestedScroll 。如何摆脱这种情况？【参考方案2】：当您将 recyclerview 的高度设置为 wrap-content 时，它会构建一次所有子视图，因为 NestedScrollView 内的 recyclerview 没有任何兄弟，您可以删除 NestedScrollVeiw 并进行如下布局：
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler"
android:layout_
android:layout_
app:layout_behavior="@string/appbar_scrolling_view_behavior"
/>
解决方案 #2： 您可以使 RecyclerView 和 RelativeLayout 的高度与父级匹配
【讨论】：
【参考方案3】：在 RecyclerView 上禁用嵌套滚动：
mRecyclerView.setNestedScrollingEnabled(false);
【讨论】：
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