Question

我使用RecyclerView选择所有选项。此选项仅选择屏幕可见项目。不是全部选择。但是我选择后从上到下滚动。有什么问题？

适配器类：

public class FilterBrandAdapter extends RecyclerView.Adapter<FilterBrandAdapter.MyViewHolder> {

    private ArrayList<FilterBrandDataModel> mBrandModelArraylist;
    private Context mContext;
    private TinyDB mPrefDb;
    private boolean isSelectedAll;
    public static final String PREF_SELECTED_ALL = "selectedAll";
    private CartTotalListener mCartListener;

    public void selectAll() {
        Log.e("onClickSelectAll", "yes");
        isSelectedAll = true;
        notifyDataSetChanged();
    }

    public void deselectAll() {
        Log.e("onClickSelectAll", "no");
        isSelectedAll = false;
        notifyDataSetChanged();
    }

    class MyViewHolder extends RecyclerView.ViewHolder {

        CheckBox cbItemTitle;


        MyViewHolder(View itemView) {
            super(itemView);

            cbItemTitle = (CheckBox) itemView.findViewById(R.id.checkBox_filter_brand_title);
            itemView.setClickable(true);

        }
    }

    public FilterBrandAdapter(BrandFilterActivity activity, ArrayList<FilterBrandDataModel> mArrayList) {

        this.mContext = activity;
        this.mBrandModelArraylist = mArrayList;
        LayoutInflater inflater = activity.getLayoutInflater();

        try {
            this.mCartListener = ((CartTotalListener) mContext);
        } catch (ClassCastException e) {
            throw new ClassCastException("Activity must implement AdapterCallback.");
        }
    }

    @Override
    public FilterBrandAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.item_recycler_brand_items, parent, false);

        mPrefDb = new TinyDB(mContext);
        return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, int position) {

        final FilterBrandDataModel brandsData = mBrandModelArraylist.get(position);

        holder.cbItemTitle.setText(mBrandModelArraylist.get(position).getCategoryName());

        //set adapter classcheckbox change listener for if clicked or not
        holder.cbItemTitle.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

                if (holder.cbItemTitle.isChecked()) {

                    //if check box checked selected checkbox saved in tinyDB
                    int getPosition = (int) buttonView.getTag();
                    mBrandModelArraylist.get(getPosition).setSelected(buttonView.isChecked());
                    mPrefDb.putBoolean(brandsData.getCategoryName(), true);
                    holder.cbItemTitle.setChecked(true);
                    Log.e("checked item-->", brandsData.getCategoryName());
                    mCartListener.onMethodCallback();


                } else {

                    //else check box un-checked selected checkbox save checkbox is un-checked in tinyDB
                    int getPosition = (int) buttonView.getTag();
                    mBrandModelArraylist.get(getPosition).setSelected(buttonView.isChecked());
                    mPrefDb.putBoolean(brandsData.getCategoryName(), false);
                    holder.cbItemTitle.setChecked(false);

                    Log.e("un-checked item-->", brandsData.getCategoryName());
                    mCartListener.onMethodCallback();

                }


            }
        });

        //select & deselect  all checkbox in recyclerview
        if (!isSelectedAll) {
            holder.cbItemTitle.setTag(position);
            holder.cbItemTitle.setChecked(mBrandModelArraylist.get(position).isSelected());
            holder.cbItemTitle.setChecked(false);

        } else {
            holder.cbItemTitle.setTag(position);
            holder.cbItemTitle.setChecked(mBrandModelArraylist.get(position).isSelected());
            holder.cbItemTitle.setChecked(true);

        }

        //save selected (or) deselect checkbox with position in tinyDB
        holder.cbItemTitle.setTag(position);
        holder.cbItemTitle.setChecked(mBrandModelArraylist.get(position).isSelected());

        boolean checked = mPrefDb.getBoolean(brandsData.getCategoryName(), true);
        holder.cbItemTitle.setChecked(checked);
    }

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

我使用interface（mCartListener.onMethodCallback（））来通知所选项目＆amp;在文本视图中显示项目计数。

我的界面：

@Override
public void onMethodCallback() {

    ArrayList<String> array = new ArrayList<>();

    //checking which items are selected in adapter class & save into array list
    for (FilterBrandDataModel brandDataModel : mArrayList) {
        if (brandDataModel.isSelected()) {
            array.add(brandDataModel.getCategoryName());
        }
    }

    int size = array.size();

    if (size == mArrayList.size()) {
        mPrefDb.putString(PREF_SELECTED_BRANDS_TOT, "true");
        String text = String.valueOf(size) + " " + getResources().getString(R.string.msg_selected);
        mBrandResults.setText(text);
    } else {
        mPrefDb.putString(PREF_SELECTED_BRANDS_TOT, "false");
        String text = String.valueOf(size) + " " + getResources().getString(R.string.msg_selected);
        mBrandResults.setText(text);
    }
}

Answer 1

RecyclerView在滚动时加载数据，但我需要其中的所有数据而不滚动。所以，我更改了RecyclerView中的ScrollView：

<ScrollView
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="0.85"
        android:overScrollMode="never"
        android:scrollbars="none">
    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:overScrollMode="never"
        />
    </ScrollView>

然后，在Activity，

RecyclerView.setNestedScrollEnabled(false);

我使用ScrollView滚动项目。那就是它。

Answer 2

问题是您只在selectAll()（ isSelectedAll = true; ）中切换标记。在您的适配器中将有例如3个可见项目（我不知道它们在您的屏幕上有多大）。一个项目由一个视图持有者表示。切换标记并调用notifyDataSetChanged()后，将为每个可见项调用函数onBindViewHolder() - ＆gt;在我的例子中3次。在此功能中，如果选中该复选框，则使用if (!isSelectedAll) {决定。因此永远不会要求所有项目。

<强>解决方案：

更改

public void selectAll() {
    Log.e("onClickSelectAll", "yes");
    isSelectedAll = true;
    notifyDataSetChanged();
}

要

public void selectAll() {
    Log.e("onClickSelectAll", "yes");
    for(FilterBrandDataModel brandsData : mBrandModelArraylist) {
         mPrefDb.putBoolean(brandsData.getCategoryName(), true);
    }
    notifyDataSetChanged();
}

同样适用于deselectAll()。

Recycler视图无法选择所有项

2 个答案: