如何在设备旋转时恢复Android RecyclerView列表项中的复选框状态

我当前的Android应用程序包含一个RecyclerView，列表中的每个项目都有一个复选框

我的问题是，在屏幕旋转时，复选框总是返回到未选中状态

我将更新后的列表项存储在我的activities ViewModel中，并将此保存的列表传递回onCreate中的适配器

从调试日志中，我可以看到列表状态正确地保存了每个列表项的选中/未选中状态

我还注销了适配器构造函数中的列表，该列表还显示选中状态仍然有效

但是，当调用

onBindViewHolder

时，列表项都未选中

以下是我的代码片段：-

  @Override
    protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.my_layout);

        manageViewModel();
        recyclerView = findViewById(R.id.my_rv);

        final LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL));
        adapter = new MedicationAdapter(viewModel.getList(), this);
        recyclerView.setAdapter(adapter);

   }



protected void onSaveInstanceState(Bundle state) {
    super.onSaveInstanceState(state);
    viewModel.saveList(adapter.getList());
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
}

<android.support.v7.widget.AppCompatCheckBox
            android:id="@+id/my_checkbox_header"
            android:layout_width="wrap_content"
            android:saveEnabled="false"
            android:layout_height="wrap_content"
            android:layout_gravity="top"
            android:text="" />

    public class MusicalAdapter extends RecyclerView.Adapter<MusicalAdapter.ViewHolder> {

        private static final String TAG = "MusicalAdapter";
        private int previousExpandedPosition = -1;
        private int mExpandedPosition = -1;

        private final List<MusicalUI> musicals = new ArrayList<>();
        private final ItemClickListener clickListener;

        MusicalAdapter(final List<MusicalUI> musicals, final ItemClickListener clickListener) {
            this.musicals.clear();
            this.musicals.addAll(musicals);
//AT THIS POINT THE CHECKED VALUES ARE AS EXPECTED

            this.clickListener = clickListener;
        }

        @NonNull
        @Override
        public MusicalAdapter.ViewHolder onCreateViewHolder(@NonNull final ViewGroup parent, final int viewType) {
            final View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.all_disco_item_x, parent, false);
            return new ViewHolder(view);
        }

        @Override
        public void onBindViewHolder(@NonNull final MusicalAdapter.ViewHolder holder, final int position) {
            final MusicalUI musical = musicals.get(position);

            Log.d(TAG, "onBindViewHolder() called with: musical = [" + musical.getChecked());

// AT THI SPOINT THE CHECKED VALUES ARE ALWAYS FALSE!!!!!!!!
            final boolean isExpanded = position == mExpandedPosition;


            for (final MusicalUI musicalx : musicals) {
                Log.d(TAG, "onBindViewHolder(): " + musicalx.getChecked());
            }

            // Header
            holder.discoDetailsHeaderLayout.setVisibility(View.VISIBLE);
            holder.musicalNameHeader.setText(musical.getDiscoName());

            holder.discoSelectedHeader.setOnCheckedChangeListener(null);
            holder.discoSelectedHeader.setChecked(musical.getChecked());
            holder.discoSelectedHeader.setOnCheckedChangeListener((buttonView, isChecked) -> musical.setChecked(isChecked));


            if (isExpanded)
                previousExpandedPosition = position;

            holder.itemView.setOnClickListener(v -> {
                mExpandedPosition = isExpanded ? -1 : position;
                notifyItemChanged(previousExpandedPosition);
                notifyItemChanged(position);
            });

        }

        @Override
        public int getItemCount() {
            return musicals.size();
        }


        MusicalUI getItem(final int position) {
            return musicals.get(position);
        }

        void updateList(final List<MusicalUI> newMusicals) {
            final DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(new GenericDiffUtilCallback<>(this.musicals, newMusicals));
            diffResult.dispatchUpdatesTo(this);

            this.musicals.clear();
            this.musicals.addAll(newMusicals);
        }

        List<MusicalUI> getList() {
            return musicals;
        }

        /**
         *
         */
        public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, CompoundButton.OnCheckedChangeListener {
    ...
            }


        }
    }

我的列表项复选框在xml中定义如下：-

  @Override
    protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.my_layout);

        manageViewModel();
        recyclerView = findViewById(R.id.my_rv);

        final LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL));
        adapter = new MedicationAdapter(viewModel.getList(), this);
        recyclerView.setAdapter(adapter);

   }



protected void onSaveInstanceState(Bundle state) {
    super.onSaveInstanceState(state);
    viewModel.saveList(adapter.getList());
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
}

<android.support.v7.widget.AppCompatCheckBox
            android:id="@+id/my_checkbox_header"
            android:layout_width="wrap_content"
            android:saveEnabled="false"
            android:layout_height="wrap_content"
            android:layout_gravity="top"
            android:text="" />

    public class MusicalAdapter extends RecyclerView.Adapter<MusicalAdapter.ViewHolder> {

        private static final String TAG = "MusicalAdapter";
        private int previousExpandedPosition = -1;
        private int mExpandedPosition = -1;

        private final List<MusicalUI> musicals = new ArrayList<>();
        private final ItemClickListener clickListener;

        MusicalAdapter(final List<MusicalUI> musicals, final ItemClickListener clickListener) {
            this.musicals.clear();
            this.musicals.addAll(musicals);
//AT THIS POINT THE CHECKED VALUES ARE AS EXPECTED

            this.clickListener = clickListener;
        }

        @NonNull
        @Override
        public MusicalAdapter.ViewHolder onCreateViewHolder(@NonNull final ViewGroup parent, final int viewType) {
            final View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.all_disco_item_x, parent, false);
            return new ViewHolder(view);
        }

        @Override
        public void onBindViewHolder(@NonNull final MusicalAdapter.ViewHolder holder, final int position) {
            final MusicalUI musical = musicals.get(position);

            Log.d(TAG, "onBindViewHolder() called with: musical = [" + musical.getChecked());

// AT THI SPOINT THE CHECKED VALUES ARE ALWAYS FALSE!!!!!!!!
            final boolean isExpanded = position == mExpandedPosition;


            for (final MusicalUI musicalx : musicals) {
                Log.d(TAG, "onBindViewHolder(): " + musicalx.getChecked());
            }

            // Header
            holder.discoDetailsHeaderLayout.setVisibility(View.VISIBLE);
            holder.musicalNameHeader.setText(musical.getDiscoName());

            holder.discoSelectedHeader.setOnCheckedChangeListener(null);
            holder.discoSelectedHeader.setChecked(musical.getChecked());
            holder.discoSelectedHeader.setOnCheckedChangeListener((buttonView, isChecked) -> musical.setChecked(isChecked));


            if (isExpanded)
                previousExpandedPosition = position;

            holder.itemView.setOnClickListener(v -> {
                mExpandedPosition = isExpanded ? -1 : position;
                notifyItemChanged(previousExpandedPosition);
                notifyItemChanged(position);
            });

        }

        @Override
        public int getItemCount() {
            return musicals.size();
        }


        MusicalUI getItem(final int position) {
            return musicals.get(position);
        }

        void updateList(final List<MusicalUI> newMusicals) {
            final DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(new GenericDiffUtilCallback<>(this.musicals, newMusicals));
            diffResult.dispatchUpdatesTo(this);

            this.musicals.clear();
            this.musicals.addAll(newMusicals);
        }

        List<MusicalUI> getList() {
            return musicals;
        }

        /**
         *
         */
        public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, CompoundButton.OnCheckedChangeListener {
    ...
            }


        }
    }

在设备旋转时，将复选框状态保留在RecyclerView项中的正确方法是什么

我的适配器代码：-

  @Override
    protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.my_layout);

        manageViewModel();
        recyclerView = findViewById(R.id.my_rv);

        final LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL));
        adapter = new MedicationAdapter(viewModel.getList(), this);
        recyclerView.setAdapter(adapter);

   }



protected void onSaveInstanceState(Bundle state) {
    super.onSaveInstanceState(state);
    viewModel.saveList(adapter.getList());
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
}

<android.support.v7.widget.AppCompatCheckBox
            android:id="@+id/my_checkbox_header"
            android:layout_width="wrap_content"
            android:saveEnabled="false"
            android:layout_height="wrap_content"
            android:layout_gravity="top"
            android:text="" />

    public class MusicalAdapter extends RecyclerView.Adapter<MusicalAdapter.ViewHolder> {

        private static final String TAG = "MusicalAdapter";
        private int previousExpandedPosition = -1;
        private int mExpandedPosition = -1;

        private final List<MusicalUI> musicals = new ArrayList<>();
        private final ItemClickListener clickListener;

        MusicalAdapter(final List<MusicalUI> musicals, final ItemClickListener clickListener) {
            this.musicals.clear();
            this.musicals.addAll(musicals);
//AT THIS POINT THE CHECKED VALUES ARE AS EXPECTED

            this.clickListener = clickListener;
        }

        @NonNull
        @Override
        public MusicalAdapter.ViewHolder onCreateViewHolder(@NonNull final ViewGroup parent, final int viewType) {
            final View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.all_disco_item_x, parent, false);
            return new ViewHolder(view);
        }

        @Override
        public void onBindViewHolder(@NonNull final MusicalAdapter.ViewHolder holder, final int position) {
            final MusicalUI musical = musicals.get(position);

            Log.d(TAG, "onBindViewHolder() called with: musical = [" + musical.getChecked());

// AT THI SPOINT THE CHECKED VALUES ARE ALWAYS FALSE!!!!!!!!
            final boolean isExpanded = position == mExpandedPosition;


            for (final MusicalUI musicalx : musicals) {
                Log.d(TAG, "onBindViewHolder(): " + musicalx.getChecked());
            }

            // Header
            holder.discoDetailsHeaderLayout.setVisibility(View.VISIBLE);
            holder.musicalNameHeader.setText(musical.getDiscoName());

            holder.discoSelectedHeader.setOnCheckedChangeListener(null);
            holder.discoSelectedHeader.setChecked(musical.getChecked());
            holder.discoSelectedHeader.setOnCheckedChangeListener((buttonView, isChecked) -> musical.setChecked(isChecked));


            if (isExpanded)
                previousExpandedPosition = position;

            holder.itemView.setOnClickListener(v -> {
                mExpandedPosition = isExpanded ? -1 : position;
                notifyItemChanged(previousExpandedPosition);
                notifyItemChanged(position);
            });

        }

        @Override
        public int getItemCount() {
            return musicals.size();
        }


        MusicalUI getItem(final int position) {
            return musicals.get(position);
        }

        void updateList(final List<MusicalUI> newMusicals) {
            final DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(new GenericDiffUtilCallback<>(this.musicals, newMusicals));
            diffResult.dispatchUpdatesTo(this);

            this.musicals.clear();
            this.musicals.addAll(newMusicals);
        }

        List<MusicalUI> getList() {
            return musicals;
        }

        /**
         *
         */
        public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, CompoundButton.OnCheckedChangeListener {
    ...
            }


        }
    }

公共类MusicalAdapter扩展了RecyclerView.Adapter{
私有静态最终字符串标记=“MusicalAdapter”；
private int previousExpandedPosition=-1；
私有int-mExpandedPosition=-1；
私人最终列表音乐剧=新ArrayList（）；
私有最终项clickListener clickListener；
MusicalAdapter（最终列表音乐剧、最终项目clickListener clickListener）{
这个。音乐剧。清晰（）；
这个。音乐剧。阿达尔（音乐剧）；
//此时，检查值与预期值相同
this.clickListener=clickListener；
}
@非空
@凌驾
public MusicalAdapter.ViewHolder onCreateViewHolder（@NonNull final ViewGroup父级，final int viewType）{
最终视图=LayoutInflater.from（parent.getContext（））.flate（R.layout.all\u disco\u item\u x，parent，false）；
返回新的ViewHolder（视图）；
}
@凌驾
public void onBindViewHolder（@NonNull final MusicalAdapter.ViewHolder，final int position）{
最终音乐剧ui music=音乐剧。获取（位置）；
d（标记“onBindViewHolder（）”，调用时使用：music=[“+music.getChecked（））；
//在该点，检查值始终为假！！！！！！！！
最终布尔值isExpanded=position==MeExpandedPosition；
为（最终音乐剧UI音乐剧：音乐剧）{
Log.d（标记“onBindViewHolder（）：”+musicalx.getChecked（））；
}
//标题
holder.discoDetailsHeaderLayout.setVisibility（View.VISIBLE）；
holder.musicalNameHeader.setText（musical.getdiscome（））；
holder.discoSelectedHeader.setOnCheckedChangeListener（空）；
holder.discoSelectedHeader.setChecked（music.getChecked（））；
holder.discoSelectedHeader.setOnCheckedChangeListener（（按钮视图，已检查）->music.setChecked（已检查））；
如果（扩展）
先前扩展的位置=位置；
holder.itemView.setOnClickListener（v->{
mExpandedPosition=isExpanded？-1：位置；
notifyItemChanged（先前的ExpandedPosition）；
（职位）变更；
});
}
@凌驾
public int getItemCount（）{
返回音乐剧。大小（）；
}
MusicalUI getItem（最终整数位置）{
返回音乐剧。获取（位置）；
}
void updateList（新音乐剧最终列表）{
final DiffUtil.diffiesult diffiesult=DiffUtil.calculateDiff（新通用diffutilcallback（this.musicals，newMusicals））；
diffResult.dispatchUpdatesTo（本）；
这个。音乐剧。清晰（）；
这部.音乐剧.addAll（新音乐剧）；
}
List getList（）{
回归音乐剧；
}
/**
*
*/
公共类ViewHolder扩展了RecyclerView.ViewHolder实现了View.OnClickListener、CompoundButton.OnCheckedChangeListener{
...
}
}
}

它之所以改变，是因为当轮换发生变化时，您的活动会重新启动。您可以编写大量代码来恢复您的状态，也可以避免重新启动。这是正确的方法

使您的活动不会在轮换更改中重新启动

在AndroidManifest中找到您的活动并添加

android:configChanges=“orientation”

Android还建议在大多数情况下避免使用它

它说让android自己处理配置更改

注意：自行处理配置更改可能会使更改更加复杂 更难使用替代资源，因为系统确实如此 不会自动为您应用它们。此技术应 当您必须避免由于故障而重新启动时，被认为是最后的选择 大多数应用程序都不建议更改配置和配置

要声明您的活动处理配置更改，请编辑 在清单文件中包含 android:configChanges属性的值表示 要处理的配置。中列出了可能的值 android:configChanges属性的文档 常用值为“方向”、“屏幕大小”和 “键盘隐藏”。“方向”值防止在 屏幕方向改变

---

检查我的答案，它会给你一个答案hint@NileshRathod，我的PoJo已经有一个布尔字段，该字段设置正确，直到我尝试在onBindViewHolder中使用它，然后它始终为false。即使我使用有效的“选中”列表创建了我的recyclerView适配器。请与我共享适配器代码