在 RecyclerView 中保存复选框状态

Question

我在RecyclerView 中有一个带有CheckBoxes 的选项列表。当我点击复选框时，状态会发生变化，但在上下滚动后，复选框的状态会丢失。

如何保存复选框的状态？我正在尝试更改适配器中的状态：

private void setAdapter() {
    if (mAdapter == null) {
        mAdapter = new FacetChildAdapter(mValues, getActivity(), query.getSpecValueAsString(mParentValue.getSlug())) {
            @Override
            protected void onCheckBoxRowClicked(CheckboxRow box, Value value, int adapterPosition) {
                if (type == FacetChildType.Brands) {
                    if (box.isChecked()) {
                        query.removeBrand(value);
                    } else {
                        query.addBrand(value);
                    }
                }

                else if (type == FacetChildType.Categories) {
                    if (box.isChecked()) {
                        query.removeCategory(value);
                    } else {
                        query.addCategory(value);
                    }
                }

                else if (type == FacetChildType.Deals) {
                    if (box.isChecked()) {
                        query.removeDealType(value);
                    } else {
                        query.addDealType(value);
                    }
                }

                else if (type == FacetChildType.Specifications) {
                    if (box.isChecked()) {
                        query.removeSpecification(mParentValue.getSlug(), value);
                    } else {
                        query.addSpecification(mParentValue.getSlug(), value);
                    }
                }

                box.setChecked(!box.isChecked());
                mHeading.setBackText(getResources().getString(R.string.apply));
            }

        };
        mRecyclerView.setAdapter(mAdapter);

    } else {
        mAdapter.setSource(query.getSpecValueAsString(mParentValue.getSlug()));
        mAdapter.refresh(mValues);
    }

}

FacetChildAdapter：

public class FacetChildAdapter extends GenericRecycleAdapter<Value, Holders.TextImageHolder> {
private String source;


public FacetChildAdapter(List<Value> list, Context context, String source) {
    super(list, context);
    this.source = source;
}

public void setSource(String source) {
    this.source = source;
}

@Override
protected void onItem(Value s) {

}

public Holders.TextImageHolder getCustomHolder(View v) {
    return new Holders.TextImageHolder(v) {
        @Override
        public void onCheckBoxRowClicked(CheckboxRow v) {
            FacetChildAdapter.this.onCheckBoxRowClicked(v, mList.get(getAdapterPosition()), getAdapterPosition());

        }
    };
}

protected void onCheckBoxRowClicked(CheckboxRow box, Value value, int adapterPosition) {

}

@Override
public int getLayout() {
    return R.layout.facet_child_row;
}

@Override
public void onSet(final Value item,final Holders.TextImageHolder holder) {
    holder.checkboxRow.setTitle(Html.fromHtml(item.getFullName()));
    holder.checkboxRow.setSubText("(" + String.valueOf(item.getCount()) + ")");
    holder.checkboxRow.setChecked(ShowProductsWithId.containsValueInValueStringLine(source, item.getSlug()));
    holder.checkboxRow.setDisabled(!item.isEnabled());

}

}

Answer 1

它可以通过两种方式维护：

1) 使用Hashmap来存储复选框视图的位置。 您可以存储位置并存储特定视图的唯一 id，然后在适配器使用后可以轻松获取其中的复选框位置。

2) 当您可以使用 Getter setter 类时，您可以在其中创建一个整数变量，然后您可以轻松地在该变量中设置位置，例如

• 当您可以选中复选框时，变量值为 1
• 如果您可以取消选中该复选框，则变量值为 0

通过以下方式保持您的复选框位置选中或取消选中。

Answer 2

class TeamNamesAdapter extends RecyclerView.Adapter<TeamNamesAdapter.ViewHolder>
        implements ItemTouchHelperAdapter, View.OnClickListener {

    private ArrayList<Person> people;

    public TeamNamesAdapter(TinyDB db) {
        people = new ArrayList<>();
        try {
            ArrayList<Object> peopleAsObjects = db.getListObject(PEOPLE, Person.class);
            for (Object obj : peopleAsObjects) {
                people.add((Person) obj);
            }

            if (db.getListObject(PEOPLE_ORDER, Person.class) == null) {
                db.putListObject(PEOPLE_ORDER, peopleAsObjects);
            }
        }
        catch (NullPointerException e) {
            return;
        }
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.team_names_list_item, null);

        ViewHolder viewHolder = new ViewHolder(view);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        Person curr = people.get(position);
        holder.name.setText(curr.name);
        holder.name.setChecked(curr.available);
    }

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

    public void addName(String name) {
        if(people.contains(name) || name.isEmpty())
            return;

        people.add(new Person(name, true));
        notifyDataSetChanged();
        update(true);
    }

    @Override
    public void onItemDismiss(int position) {
        people.remove(position);
        notifyItemRemoved(position);
        update(true);
    }

    @Override
    public void onItemMove(int fromPosition, int toPosition) {
        if (fromPosition < toPosition) {
            for (int i = fromPosition; i < toPosition; i++) {
                Collections.swap(people, i, i + 1);
            }
        }
        else {
            for (int i = fromPosition; i > toPosition; i--) {
                Collections.swap(people, i, i - 1);
            }
        }
        notifyItemMoved(fromPosition, toPosition);
        update(true);
        undoRandomizeButton.setEnabled(false);
    }

    @Override
    public void onClick(View v) {
        if (!(v instanceof CheckedTextView))
            return;

        CheckedTextView ctv = (CheckedTextView) v;
        ctv.toggle();

        String name = ctv.getText().toString();
        for (Person p : people) {
            if (p.name.equals(name)) {
                p.available = ctv.isChecked();
                update(true);
                return;
            }
        }
    }

    class ViewHolder extends RecyclerView.ViewHolder {
        CheckedTextView name;
        public ViewHolder(View itemView) {
            super(itemView);

            name = (CheckedTextView)itemView.findViewById(R.id.name_in_list);
            name.setOnClickListener(TeamNamesAdapter.this);
        }
    }
}

这是一个用于保存 CheckedTextView 的列表的 recyclerview 适配器。我保存了一个名为Person 的类，它包含一个字符串和一个布尔值。您的情况类似，因为您只能在 ArrayList 中保存布尔值（而不是 Person），并且在 onBindViewHolder 上，将 checkbox.isChecked 设置为该位置的布尔值。您可以在 RecyclerView 适配器上设置View.OnClickerListener，并将ViewHolder onClickListener 设置为YourAdapterName.this。并像我一样实施该方法，只需忽略Person 的东西，只需更新您的boolean 您可以在适配器onBindViewHolder 方法上看到，