Question

是否可以同时展开和折叠CardView中的多个RecyclerView？我用两个按钮创建了一个标题（用于RecyclerView），但是我不确定单击事件中需要做什么。

RecyclerView适配器类

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

    private static final int TYPE_HEADER = 0;
    private static final int TYPE_ITEM = 1;

    public boolean isSupposedToBeCollapsed;

    private Context mContext;

    RecyclerViewHeader header;
    List<RecyclerViewItem> listItems;
    ValueAnimator mAnimator;



    public MyRecyclerAdapter(Context context, RecyclerViewHeader header, List<RecyclerViewItem> listItems)
    {
        this.mContext = context;
        this.header = header;
        this.listItems = listItems;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        if(viewType == TYPE_HEADER)
        {
            View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_header, parent, false);
            return new MyRecyclerAdapter.VHHeader(v);
        }
        else if(viewType == TYPE_ITEM)
        {
            View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_item, parent, false);
            return new MyRecyclerAdapter.VHItem(v);
        }
        throw new RuntimeException("there is no type that matches the type " + viewType + " + make sure your using types correctly");
    }

    private RecyclerViewItem getItem(int position)
    {
        return listItems.get(position);
    }


    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        final Typeface iconFont = FontManager.getTypeface(mContext, FontManager.FONTAWESOME);

        if (holder instanceof VHHeader)
        {
            final VHHeader vhHeader = (VHHeader)holder;

            vhHeader.btnExpandAll.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(isSupposedToBeCollapsed){
                    // change visibility to 'VISIBLE'
                    txtB.setVisibility(View.VISIBLE);

                    // change direction of chevron to 'up'
                    txtExpandCollapse.setText(R.string.fa_icon_chevron_up);

                    // apply animation to the height of 'txtB'
                    mAnimator = slideAnimator(0, textBHeight);

                    // start the animation
                    mAnimator.start();
                    }
                    else{

                    }
                }
            });

            vhHeader.btnCollapseAll.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(isSupposedToBeCollapsed){
                        // change visibility to 'VISIBLE'
                        txtB.setVisibility(View.VISIBLE);

                        // change direction of chevron to 'up'
                        txtExpandCollapse.setText(R.string.fa_icon_chevron_up);

                        // apply animation to the height of 'txtB'
                        mAnimator = slideAnimator(0, textBHeight);

                        // start the animation
                        mAnimator.start();
                    }
                    else{

                    }
                }
            });
        }
        else if (holder instanceof VHItem)
        {

            RecyclerViewItem currentItem = getItem(position-1);
            final VHItem vhItem = (VHItem)holder;

            vhItem.txtA.setText(currentItem.getTitle());
            vhItem.txtB.setText(currentItem.getDescription());

            vhItem.txtB.setVisibility(View.GONE);

            vhItem.txtExpandCollapse.setText(R.string.fa_icon_chevron_down);
            vhItem.txtExpandCollapse.setTypeface(iconFont);

            //Add onPreDrawListener
            vhItem.txtB.getViewTreeObserver().addOnPreDrawListener(
            new ViewTreeObserver.OnPreDrawListener() {

                @Override
                public boolean onPreDraw() {
                    vhItem.txtB.getViewTreeObserver().removeOnPreDrawListener(this);
                    vhItem.txtB.setVisibility(View.GONE);

                    final int widthSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
                    final int heightSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
                    vhItem.txtB.measure(widthSpec, heightSpec);

                    vhItem.textBHeight = vhItem.txtB.getMeasuredHeight();

                    return true;
                }
            });

            vhItem.cardView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(vhItem.txtB.getVisibility() == View.GONE){
                        vhItem.expand();
                    } else {
                        vhItem.collapse();
                    }
                }
            });

            vhItem.mLinearLayout.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(vhItem.txtB.getVisibility() == View.GONE){
                        vhItem.expand();
                    } else {
                        vhItem.collapse();
                    }
                }
            });

            vhItem.txtExpandCollapse.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(vhItem.txtB.getVisibility() == View.GONE){
                        vhItem.expand();
                    } else {
                        vhItem.collapse();
                    }
                }
            });
        }
    }

    // need to override this method
    @Override
    public int getItemViewType(int position) {
        if(isPositionHeader(position))
            return TYPE_HEADER;
            return TYPE_ITEM;
    }

    private boolean isPositionHeader(int position)
    {
        return position == 0;
    }

    // increasing getItemcount to 1. This will be the row of header.
    @Override
    public int getItemCount() {
        return listItems.size()+1;
    }

    class VHHeader extends RecyclerView.ViewHolder{
        Button btnCollapseAll, btnExpandAll;

        public VHHeader(View headerView) {
            super(headerView);

            this.btnCollapseAll = headerView.findViewById(R.id.btn_collapseall);
            this.btnExpandAll = headerView.findViewById(R.id.btn_expandall);
        }
    }

    public class VHItem extends RecyclerView.ViewHolder{
        CardView cardView;
        LinearLayout mLinearLayout;
        RecyclerView mRecyclerView;
        RelativeLayout mRelativeLayout;
        TextView txtExpandCollapse, txtA, txtB;
        public int textBHeight;

        public VHItem(View itemView) {
            super(itemView);

            this.cardView = itemView.findViewById(R.id.cv);
            this.mLinearLayout = itemView.findViewById(R.id.cardview_tconnections_titlerow);
            this.mRelativeLayout = itemView.findViewById(R.id.my_relativelayout);
            this.mRecyclerView = itemView.findViewById(R.id.my_recyclerview);
            this.txtExpandCollapse = itemView.findViewById(R.id.tv_expandcollapse);
            this.txtA = itemView.findViewById(R.id.tv_A);
            this.txtB = itemView.findViewById(R.id.tv_B);
        }

        private void expand() {
            // change visibility to 'VISIBLE'
            txtB.setVisibility(View.VISIBLE);

            // change direction of chevron to 'up'
            txtExpandCollapse.setText(R.string.fa_icon_chevron_up);

            // apply animation to the height of 'txtB'
            mAnimator = slideAnimator(0, textBHeight);

            // start the animation
            mAnimator.start();
        }

        private void collapse() {
            // change direction of chevron to 'down'
            txtExpandCollapse.setText(R.string.fa_icon_chevron_down);

            int finalHeight = txtB.getHeight();

            ValueAnimator mAnimator = slideAnimator(finalHeight, 0);

            mAnimator.addListener(new Animator.AnimatorListener() {
                @Override
                public void onAnimationEnd(Animator animator) {
                    txtB.setVisibility(View.GONE);
                }

                @Override
                public void onAnimationStart(Animator animator) {
                }

                @Override
                public void onAnimationCancel(Animator animator) {
                }

                @Override
                public void onAnimationRepeat(Animator animator) {
                }
            });
            mAnimator.start();
        }


        public ValueAnimator slideAnimator(int start, int end) {

            ValueAnimator animator = ValueAnimator.ofInt(start, end);


            animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
                @Override
                public void onAnimationUpdate(ValueAnimator valueAnimator) {
                    // update height
                    int value = (Integer) valueAnimator.getAnimatedValue();

                    ViewGroup.LayoutParams layoutParams = txtB.getLayoutParams();
                    layoutParams.height = value;
                    txtB.setLayoutParams(layoutParams);
                }
            });
            return animator;
        }
    }
}

片段类

public class MyFragment extends android.support.v4.app.Fragment {

    private MyRecyclerAdapter adapter;

    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);
        linearLayoutManager = new LinearLayoutManager(getActivity());

        MyRecyclerAdapter adapter = new MyRecyclerAdapter(getContext(), getHeader(), getListItems());
        recyclerView.setLayoutManager(linearLayoutManager);
        recyclerView.setAdapter(adapter);

        super.onActivityCreated(savedInstanceState);
    }

    RecyclerView recyclerView;
    LinearLayoutManager linearLayoutManager;

    public RecyclerViewHeader getHeader()
    {
        return new RecyclerViewHeader();
    }

    public List<RecyclerViewItem> getListItems()
    {
        List<RecyclerViewItem> rvItems = new ArrayList<>();

        RecyclerViewItem itemA = new RecyclerViewItem();
        itemA.setConnectionMode("Item A");
        itemA.setConnectionName("Feature A1");
        rvItems.add(itemA);

        RecyclerViewItem itemB = new RecyclerViewItem();
        itemB.setConnectionMode("Item B");
        itemB.setConnectionName("Feature B1\nFeature B2");
        rvItems.add(itemB);

        RecyclerViewItem itemC = new RecyclerViewItem();
        itemC.setConnectionMode("Item C");
        itemC.setConnectionName("Feature C1\nFeature C2\nFeature C3");
        rvItems.add(itemC);


        return rvItems;
    }
}

Answer 1

您可以做的是，设置一个变量（布尔值），该变量在RecyclerAdapter代码中存储卡的状态（展开/折叠）。
然后，在您的onBindViewHolder代码块中，编写一段代码来检查是否应使用上述变量和所需的显示代码来扩展或折叠卡。

示例：

if(isSuppossedToBeCollapsed){
    textView.setVisibility = false;
}
else{
    textView.setVisibility = true;
}

然后，当您单击按钮时，可以在RecyclerAdapter代码中调用notifyDatasetChanged来更新回收器视图，该按钮将重新绘制视图并相应地反映卡的状态（展开/折叠）。

NotifyDatasetChanged Documentation

ExpandableRecyclerView-如何同时扩展和折叠多个CardView

1 个答案: