Question

每当单击特定按钮时，我都试图显示或隐藏RecyclerView项，但由于某种原因什么也没发生。我什至尝试使用adapter.notifyDataSetChanged();。要解决什么问题，以便在单击必要的按钮（全部展开或全部折叠）时可以看到或消失此RecyclerView中的所有项目？

public class MyFragment extends android.support.v4.app.Fragment {
    private static final String TAG = MyActivity.class.getSimpleName();

    public Boolean isSupposedToBeCollapsed;
    private static final int ITEM_TYPE = 100;
    private static final int HEADER_TYPE = 101;
    private static final int HEADER_TYPE_2 = 102;
    private static final int INTRO_TYPE = 103;

    public MyFragment() {}

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        return inflater.inflate(R.layout.fragment_rv, container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        View v = getView();
        assert v != null;

        recyclerView = v.findViewById(R.id.my_recyclerview);
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false));

        // SpannableStrings
        int[] attrS = {R.attr.spannablestringtextColor};
        TypedArray ta = getActivity().getTheme().obtainStyledAttributes(attrS);
        int colorSS = ta.getColor(0, Color.BLACK); //Color.BLACK - default value (colour will change automatically depending on chosen theme)
        Log.d(TAG, "clickMethod 1) " + Integer.toHexString(colorSS));
        ta.recycle();


        // SpannableString (start)
        SpannableStringBuilder ssb1 = new SpannableStringBuilder();

        SpannableString str1a = new SpannableString(getString(R.string.placeholder1_placeholder2_placeholder3,
                " ", getString(R.string.title_1a), " "));
        str1a.setSpan(new BackgroundColorSpan(Color.BLACK), 0, str1a.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        str1a.setSpan(new ForegroundColorSpan(ContextCompat.getColor(getContext(), R.color.yellow)), 0, str1a.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        ssb1.append(str1a);

        SpannableString str1b = new SpannableString(" " + getString(R.string.title_1b));
        str1b.setSpan(new ForegroundColorSpan(colorSS), 0, str1b.length(), 0);
        ssb1.append(str1b);
        // SpannableString (end)


        // SpannableString (start)
        SpannableStringBuilder ssb2 = new SpannableStringBuilder();

        SpannableString str2a = new SpannableString(getString(R.string.title_2a));
        str2a.setSpan(new BackgroundColorSpan(Color.BLACK), 0, str2a.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        str2a.setSpan(new ForegroundColorSpan(ContextCompat.getColor(getContext(), R.color.yellow)), 0, str2a.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
        ssb2.append(str2a);

        SpannableString str2b = new SpannableString(", " + getString(R.string.title_2b));
        str2b.setSpan(new ForegroundColorSpan(colorSS), 0, str2b.length(), 0);
        ssb2.append(str2b);
        // SpannableString (end)


        // init data
        dataTitle = new ArrayList<>();
        dataTitle.add(ssb1);
        dataTitle.add(ssb2);
        dataTitle.add(getString(R.string.title_c));
        dataTitle.add(getString(R.string.title_d));

        dataSubtitle = new ArrayList<>();
        dataSubtitle.add(getString(R.string.subtitle_a));
        dataSubtitle.add(getString(R.string.subtitle_b));
        dataSubtitle.add(getString(R.string.subtitle_c));
        dataSubtitle.add(getString(R.string.subtitle_d));

        dataDescription = new ArrayList<>();
        dataDescription.add(getString(R.string.description_a));
        dataDescription.add(getString(R.string.description_b));
        dataDescription.add(getString(R.string.description_c));
        dataDescription.add(getString(R.string.description_d));

        adapter = createAdapter();

        recyclerView.setAdapter(adapter);

        super.onActivityCreated(savedInstanceState);
    }

    RecyclerView recyclerView;
    ArrayList<CharSequence> dataTitle;
    ArrayList<String> dataSubtitle;
    ArrayList<String> dataDescription;
    RecyclerView.Adapter<MyFragment.ViewHolder> adapter;


    // creates the adapter
    private RecyclerView.Adapter<MyFragment.ViewHolder> createAdapter() {
        return new RecyclerView.Adapter<TabFragmentWATTerminus.ViewHolder>() {
            public Boolean expandedAll;
            public Boolean collapsedAll;

            @NonNull
            @Override
            public MyFragment.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int type) {
                switch (type) {
                    case HEADER_TYPE:
                        return new MyFragment.ViewHolder(inflateHelper(R.layout.recyclerview_header, parent));

                    case HEADER_TYPE_2:
                        return new MyFragment.ViewHolder(inflateHelper(R.layout.recyclerview_header, parent));

                    case ITEM_TYPE:
                        return new MyFragment.ViewHolder(inflateHelper(R.layout.recyclerview_item_tv_itemtype, parent));

                    case INTRO_TYPE:
                        return new MyFragment.ViewHolder(inflateHelper(R.layout.recyclerview_item_tv_intro, parent));

                    default:
                        return new TabFragmentWATTerminus.ViewHolder(inflateHelper(R.layout.recyclerview_item_tv_itemtype, parent));
                }
            }


            @Override
            public void onBindViewHolder(@NonNull final MyFragment.ViewHolder viewHolder, int position) {
                final Typeface iconFont = FontManager.getTypeface(getContext(), FontManager.FONTAWESOME);

                final RelativeLayout rlInformation = viewHolder.itemView.findViewById(R.id.rl_information);


                switch (getItemViewType(position)) {
                    case HEADER_TYPE:
                        Button expandButton = viewHolder.itemView.findViewById(R.id.button);
                        expandButton.setText(R.string.expand_all);

                    expandButton.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            if(expandedAll){
                                expandedAll = true;
                                expandRL(rlInformation, txtArrowTV);
                                adapter.notifyDataSetChanged();
                            } else if(collapsedAll){
                                collapsedAll = true;
                                collapseRL(rlInformation, txtArrowTV);
                                adapter.notifyDataSetChanged();
                            }
                        }
                    });

                        break;
                    case HEADER_TYPE_2:
                        Button collapseButton = viewHolder.itemView.findViewById(R.id.button);
                        collapseButton.setText(R.string.collapse_all);

                        collapseButton.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                            if(rlInformation.getVisibility() == View.VISIBLE){                                                                                 collapseRL(rlInformation, txtArrowTV);
                                    adapter.notifyDataSetChanged();
                            }
                        });
                        break;
                    case INTRO_TYPE:
                        TextView tvIntroA = viewHolder.itemView.findViewById(R.id.tv_placeholder;
                        tvIntroA.setVisibility(View.GONE);
                        break;
                    case ITEM_TYPE:
                        // get the current item
                        CharSequence itemA = dataTitle.get(position - 3);
                        String itemB = dataSubtitle.get(position - 3);
                        String itemC = dataDescription.get(position - 3);

                        //
                        final TextView txtTitle = viewHolder.itemView.findViewById(R.id.tv_title);
                        txtTitle.setText(itemA);

                        final TextView txtSubtitle = viewHolder.itemView.findViewById(R.id.tv_subtitle);
                        txtSubtitle.setText(itemB);

                        final TextView txtDescription = viewHolder.itemView.findViewById(R.id.tv_description);
                        txtDescription.setText(itemC);

                        final TextView txtArrowTV = viewHolder.itemView.findViewById(R.id.tv_expandcollapsearrow);
                        txtArrowTV.setText(R.string.fa_icon_chevron_down);
                        txtArrowTV.setTypeface(iconFont);

//                        final RelativeLayout rlInformation = viewHolder.itemView.findViewById(R.id.rl_information);
                        rlInformation.setVisibility(View.GONE);

                        //
                        CardView cardView = viewHolder.itemView.findViewById(R.id.cardview_item);
                        LinearLayout mLinearLayoutTV = viewHolder.itemView.findViewById(R.id.cardview_titlerow);

                        //
                        cardView.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                if(rlInformation.getVisibility() == View.GONE){
                                    expandRL(rlInformation, txtArrowTV);
                                } else {
                                    collapseRL(rlInformation, txtArrowTV);
                                }
                            }
                        });

                        mLinearLayoutTV.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                if(rlInformation.getVisibility() == View.GONE){
                                    expandRL(rlInformation, txtArrowTV);
                                } else {
                                    collapseRL(rlInformation, txtArrowTV);
                                }
                            }
                        });

                        txtArrowTV.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View v) {
                                if(rlInformation.getVisibility() == View.GONE){
                                    expandRL(rlInformation, txtArrowTV);
                                } else {
                                    collapseRL(rlInformation, txtArrowTV);
                                }
                            }
                        });
                        break;
                }
            }

            @Override
            public int getItemCount() {
                return dataTitle.size() + 3;
            }

            @Override
            public int getItemViewType(int position) {
                switch (position) {
                    case 0:
                        return HEADER_TYPE;
                    case 1:
                        return HEADER_TYPE_2;
                    case 2:
                        return INTRO_TYPE;
                    default: return ITEM_TYPE;
                }
            }
        };
    }

    private View inflateHelper(int resId, ViewGroup parent) {
        return LayoutInflater.from(getActivity()).inflate(resId, parent, false);
    }

    // inner class for viewholder to use,
    class ViewHolder extends RecyclerView.ViewHolder {
        ViewHolder(@NonNull View itemView) {
            super(itemView);
        }
    }

    public void expandRL(final RelativeLayout rlInformation, final TextView txtArrowTV) {
        rlInformation.setVisibility(View.VISIBLE);
        txtArrowTV.setText(R.string.fa_icon_chevron_up);
    }

    public void collapseRL(final RelativeLayout rlInformation, final TextView txtArrowTV) {
        rlInformation.setVisibility(View.GONE);
        txtArrowTV.setText(R.string.fa_icon_chevron_down);
    }
}

Answer 1

编辑括号中的代码有点困难，因为花括号不是一对。无论如何，您应该在适配器类中定义两个boolean字段（例如expandedAll和collapsedAll）。在collapseButton和expandButton的点击侦听器中，为expandedAll和collapsedAll设置正确的值，然后调用notifyDataSetChanged()。之后，在onBindViewHolder中，当视图类型为ITEM_TYPE时，检查expandedAll和collapsedAll的值：

在MyFragment中：

private RecyclerView.Adapter<MyFragment.ViewHolder> createAdapter() {
    return new MyAdapter(dataTitle, dataSubtitle, dataDescription);
}

MyAdapter.java：

public class MyAdapter extends RecyclerView.Adapter<MyFragment.ViewHolder> {

    public static final int ITEM_TYPE = 100;
    public static final int HEADER_TYPE = 101;
    public static final int HEADER_TYPE_2 = 102;
    public static final int INTRO_TYPE = 103;

    private ArrayList<CharSequence> dataTitle;
    private ArrayList<String> dataSubtitle;
    private ArrayList<String> dataDescription;

    private Boolean expandedAll;
    private Boolean collapsedAll;

    public MyAdapter(ArrayList<CharSequence> dataTitle, ArrayList<String> dataSubtitle, ArrayList<String> dataDescription) {
        this.dataTitle = dataTitle;
        this.dataSubtitle = dataSubtitle;
        this.dataDescription = dataDescription;
    }

    @NonNull
    @Override
    public MyFragment.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int type) {
        switch (type) {
            case HEADER_TYPE:
                return new MyFragment.ViewHolder(inflateHelper(parent.getContext(), R.layout.recyclerview_header, parent));

            case HEADER_TYPE_2:
                return new MyFragment.ViewHolder(inflateHelper(parent.getContext(), R.layout.recyclerview_header, parent));

            case ITEM_TYPE:
                return new MyFragment.ViewHolder(inflateHelper(parent.getContext(), R.layout.recyclerview_item_tv_itemtype, parent));

            case INTRO_TYPE:
                return new MyFragment.ViewHolder(inflateHelper(parent.getContext(), R.layout.recyclerview_item_tv_intro, parent));

            default:
                return new TabFragmentWATTerminus.ViewHolder(inflateHelper(parent.getContext(), R.layout.recyclerview_item_tv_itemtype, parent));
        }
    }

    @Override
    public void onBindViewHolder(@NonNull MyFragment.ViewHolder viewHolder, int position) {
        final Typeface iconFont = FontManager.getTypeface(getContext(), FontManager.FONTAWESOME);
        final RelativeLayout rlInformation = viewHolder.itemView.findViewById(R.id.rl_information);

        switch (getItemViewType(position)) {
            case HEADER_TYPE:
                Button expandButton = viewHolder.itemView.findViewById(R.id.button);
                expandButton.setText(R.string.expand_all);

                expandButton.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        expandedAll = true;
                        collapsedAll = false;
                        notifyDataSetChanged();
                    }
                });

                break;
            case HEADER_TYPE_2:
                Button collapseButton = viewHolder.itemView.findViewById(R.id.button);
                collapseButton.setText(R.string.collapse_all);

                collapseButton.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        expandedAll = false;
                        collapsedAll = true;
                        notifyDataSetChanged();
                    }
                });
                break;
            case INTRO_TYPE:
                TextView tvIntroA = viewHolder.itemView.findViewById(R.id.tv_placeholder;
                tvIntroA.setVisibility(View.GONE);
                break;
            case ITEM_TYPE:
                // get the current item
                CharSequence itemA = dataTitle.get(position - 3);
                String itemB = dataSubtitle.get(position - 3);
                String itemC = dataDescription.get(position - 3);

                //
                final TextView txtTitle = viewHolder.itemView.findViewById(R.id.tv_title);
                txtTitle.setText(itemA);

                final TextView txtSubtitle = viewHolder.itemView.findViewById(R.id.tv_subtitle);
                txtSubtitle.setText(itemB);

                final TextView txtDescription = viewHolder.itemView.findViewById(R.id.tv_description);
                txtDescription.setText(itemC);

                final TextView txtArrowTV = viewHolder.itemView.findViewById(R.id.tv_expandcollapsearrow);
                txtArrowTV.setText(R.string.fa_icon_chevron_down);
                txtArrowTV.setTypeface(iconFont);

//                        final RelativeLayout rlInformation = viewHolder.itemView.findViewById(R.id.rl_information);
                rlInformation.setVisibility(View.GONE);

                //
                CardView cardView = viewHolder.itemView.findViewById(R.id.cardview_item);
                LinearLayout mLinearLayoutTV = viewHolder.itemView.findViewById(R.id.cardview_titlerow);

                //
                cardView.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        if (rlInformation.getVisibility() == View.GONE) {
                            expandRL(rlInformation, txtArrowTV);
                        } else {
                            collapseRL(rlInformation, txtArrowTV);
                        }
                    }
                });

                mLinearLayoutTV.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        if (rlInformation.getVisibility() == View.GONE) {
                            expandRL(rlInformation, txtArrowTV);
                        } else {
                            collapseRL(rlInformation, txtArrowTV);
                        }
                    }
                });

                txtArrowTV.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        if (rlInformation.getVisibility() == View.GONE) {
                            expandRL(rlInformation, txtArrowTV);
                        } else {
                            collapseRL(rlInformation, txtArrowTV);
                        }
                    }
                });

                if (expandedAll) {
                    expandRL(rlInformation, txtArrowTV);
                } else if (collapsedAll) {
                    collapseRL(rlInformation, txtArrowTV);
                }

                break;
        }
    }

    @Override
    public int getItemCount() {
        return dataTitle.size() + 3;
    }

    @Override
    public int getItemViewType(int position) {
        switch (position) {
            case 0:
                return HEADER_TYPE;
            case 1:
                return HEADER_TYPE_2;
            case 2:
                return INTRO_TYPE;
            default:
                return ITEM_TYPE;
        }
    }

    private View inflateHelper(Context context, int resId, ViewGroup parent) {
        return LayoutInflater.from(context).inflate(resId, parent, false);
    }

}

以上解决方案解决了所有问题的扩展和折叠，但另一个问题仍然存在。您应该为显示该项目已折叠或展开的每个项目维护一个boolean。我已经在名为PrimeAdapter的开源库中处理了RecyclerView项的扩展。（它具有android java示例应用程序）如果您愿意，我建议您使用它。它使您的代码更简单。

RecyclerView项目不会一次全部更改可见性

1 个答案: