Spinner實(shí)現(xiàn)選項(xiàng)的分組折疊動(dòng)畫

要實(shí)現(xiàn)Spinner選項(xiàng)的分組折疊動(dòng)畫，可以通過以下步驟進(jìn)行：

1. 創(chuàng)建一個(gè)自定義的SpinnerAdapter類，繼承自BaseAdapter，并實(shí)現(xiàn)SpinnerAdapter接口的方法。

2. 在SpinnerAdapter中，定義一個(gè)內(nèi)部類GroupItem來表示分組信息，包括分組標(biāo)題和選項(xiàng)列表。

3. 在getView()方法中，根據(jù)position獲取對(duì)應(yīng)的GroupItem對(duì)象，并根據(jù)其isExpanded屬性來確定是否展開或折疊選項(xiàng)。

4. 在展開或折疊選項(xiàng)時(shí)，可以通過屬性動(dòng)畫實(shí)現(xiàn)平滑的動(dòng)畫效果。例如，使用ValueAnimator來改變選項(xiàng)的高度，從而實(shí)現(xiàn)展開或折疊的效果。

以下是一個(gè)簡(jiǎn)單的示例代碼：

public class MySpinnerAdapter extends BaseAdapter implements SpinnerAdapter {
    private Context mContext;
    private List<GroupItem> mGroupItems;

    public MySpinnerAdapter(Context context, List<GroupItem> groupItems) {
        mContext = context;
        mGroupItems = groupItems;
    }

    @Override
    public int getCount() {
        return mGroupItems.size();
    }

    @Override
    public Object getItem(int position) {
        return mGroupItems.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        GroupItem groupItem = mGroupItems.get(position);
        View view = LayoutInflater.from(mContext).inflate(R.layout.item_spinner_group, parent, false);
        TextView tvTitle = view.findViewById(R.id.tv_title);
        tvTitle.setText(groupItem.getTitle());

        LinearLayout llOptions = view.findViewById(R.id.ll_options);
        if (groupItem.isExpanded()) {
            llOptions.setVisibility(View.VISIBLE);
        } else {
            llOptions.setVisibility(View.GONE);
        }

        llOptions.removeAllViews();
        for (String option : groupItem.getOptions()) {
            View optionView = LayoutInflater.from(mContext).inflate(R.layout.item_spinner_option, llOptions, false);
            TextView tvOption = optionView.findViewById(R.id.tv_option);
            tvOption.setText(option);
            llOptions.addView(optionView);
        }

        view.setOnClickListener(v -> {
            if (groupItem.isExpanded()) {
                collapseOptions(llOptions);
            } else {
                expandOptions(llOptions);
            }
            groupItem.setExpanded(!groupItem.isExpanded());
        });

        return view;
    }

    private void expandOptions(View view) {
        ValueAnimator animator = ValueAnimator.ofInt(0, view.getMeasuredHeight());
        animator.addUpdateListener(animation -> {
            int value = (int) animation.getAnimatedValue();
            ViewGroup.LayoutParams layoutParams = view.getLayoutParams();
            layoutParams.height = value;
            view.setLayoutParams(layoutParams);
        });
        animator.setDuration(300);
        animator.start();
    }

    private void collapseOptions(View view) {
        ValueAnimator animator = ValueAnimator.ofInt(view.getMeasuredHeight(), 0);
        animator.addUpdateListener(animation -> {
            int value = (int) animation.getAnimatedValue();
            ViewGroup.LayoutParams layoutParams = view.getLayoutParams();
            layoutParams.height = value;
            view.setLayoutParams(layoutParams);
        });
        animator.setDuration(300);
        animator.start();
    }

    public static class GroupItem {
        private String title;
        private List<String> options;
        private boolean expanded;

        public GroupItem(String title, List<String> options) {
            this.title = title;
            this.options = options;
            this.expanded = false;
        }

        public String getTitle() {
            return title;
        }

        public List<String> getOptions() {
            return options;
        }

        public boolean isExpanded() {
            return expanded;
        }

        public void setExpanded(boolean expanded) {
            this.expanded = expanded;
        }
    }
}

在上面的代碼中，MySpinnerAdapter類實(shí)現(xiàn)了SpinnerAdapter接口，并通過自定義的GroupItem類來表示分組信息。在getView()方法中，根據(jù)GroupItem對(duì)象的isExpanded屬性來展開或折疊選項(xiàng)，并通過屬性動(dòng)畫實(shí)現(xiàn)平滑的動(dòng)畫效果。GroupItem類包含了分組標(biāo)題、選項(xiàng)列表和展開狀態(tài)的屬性。