Spinner實現選項的拖拽排序與位置記憶

要實現Spinner選項的拖拽排序與位置記憶，可以通過自定義Adapter來實現。下面是一個簡單的示例代碼：

public class DragSortSpinnerAdapter extends ArrayAdapter<String> implements View.OnTouchListener {

    private SparseBooleanArray selectedItems;
    private int lastPosition = -1;

    public DragSortSpinnerAdapter(Context context, int resource, List<String> objects) {
        super(context, resource, objects);
        selectedItems = new SparseBooleanArray();
    }

    @Override
    public View getDropDownView(int position, View convertView, ViewGroup parent) {
        View view = super.getDropDownView(position, convertView, parent);
        view.setTag(position);
        view.setOnTouchListener(this);
        return view;
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        View view = (View) v.getParent();
        int position = (int) view.getTag();

        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                lastPosition = position;
                break;

            case MotionEvent.ACTION_MOVE:
                if(lastPosition != -1 && lastPosition != position) {
                    String item = getItem(lastPosition);
                    remove(item);
                    insert(item, position);
                    selectedItems.clear();
                    selectedItems.put(position, true);
                    notifyDataSetChanged();
                    lastPosition = position;
                }
                break;

            default:
                lastPosition = -1;
                break;
        }

        return true;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view = super.getView(position, convertView, parent);
        if(selectedItems.get(position)) {
            view.setBackgroundColor(Color.LTGRAY);
        } else {
            view.setBackgroundColor(Color.TRANSPARENT);
        }
        return view;
    }
}

在使用Spinner時，可以使用這個自定義Adapter來實現拖拽排序和位置記憶的功能。當用戶在Spinner選項上按下并移動時，會觸發onTouch方法，Adapter會根據移動的位置重新排序選項，并在getView方法中根據selectedItems來設置選中項的背景色。這樣就可以實現Spinner選項的拖拽排序與位置記憶功能了。