自定义listview实现类似通讯录的分组

以你之姓@ 2022-06-15 09:26 254阅读 0赞

//适配器
    public class SortAdapter extends BaseAdapter implements SectionIndexer {
        private List<CityModel> list=null;
        private Context mContext;
        public SortAdapter(Context context,List<CityModel> list){
            this.list=list;
            this.mContext=context;
        }
    
        /*
        * 当listview数据发生变化时，调用此方法更新list view
        * */
        public  void updateListView(List<CityModel> list){
            this.list=list;
            notifyDataSetChanged();
        }
    
        @Override
        public int getCount() {
            return list.size();
        }
    
        @Override
        public Object getItem(int i) {
            return list.get(i);
        }
    
        @Override
        public long getItemId(int i) {
            return i;
        }
    
        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
            ViewHolder viewHolder=null;
            final CityModel mContent=list.get(i);
            if (view==null){
                viewHolder=new ViewHolder();
                view= LayoutInflater.from(mContext).inflate(R.layout.item_city_selector,null);
                viewHolder.tvTitle= (TextView) view.findViewById(R.id.title);
                viewHolder.tvLetter= (TextView) view.findViewById(R.id.catalog);
                view.setTag(viewHolder);
            }else {
                viewHolder=(ViewHolder) view.getTag();
            }
            //根据position获取分类首字母的char值
            int section=getSectionForPosition(i);
            //如果当前位置等于=该分类首字母的位置则认为是 第一次出现
            if(i==getPositionForSection(section)){
                viewHolder.tvLetter.setVisibility(View.VISIBLE);
                viewHolder.tvLetter.setText(mContent.getFirstName());
            }else {
                viewHolder.tvLetter.setVisibility(View.GONE);
            }
            viewHolder.tvTitle.setText(this.list.get(i).getName());
    
            return view;
        }
        final static class ViewHolder {
            TextView tvLetter;
            TextView tvTitle;
        }
        /*
        * 根据listview的当前您位置获取分类的首字母
        * */
        public int getSectionForPosition(int position){
            return list.get(position).getFirstName().charAt(0);
        }
        /*
        * 根据分类的首字母获取其第一次出现该字母的位置
        * */
        public  int getPositionForSection(int section){
            for (int i=0;i<getCount();i++){
                String sortStr=list.get(i).getFirstName();
                char firstChar=sortStr.toUpperCase().charAt(0);
                if (firstChar == section) {
                    return i;
                }
            }
    
            return -1;
        }
        /**
         * 提取英文的首字母，非英文字母用#代替。
         */
        private String getAlpha(String str) {
            String sortStr = str.trim().substring(0, 1).toUpperCase();
            // 正则表达式，判断首字母是否是英文字母
            if (sortStr.matches("[A-Z]")) {
                return sortStr;
            } else {
                return "#";
            }
        }
    
        @Override
        public Object[] getSections() {
            return null;
        }
    
    }

//布局
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:gravity="center_vertical"
        android:background="@color/white"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
    <TextView
        android:id="@+id/catalog"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#E0E0e0"
        android:textColor="#454545"
        android:layout_weight="1"
        android:paddingTop="5dp"
        android:paddingLeft="10dp"
        android:paddingBottom="5dp"
        android:text="A"/>
        <TextView
            android:id="@+id/title"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_gravity="center_vertical"
            android:gravity="center_vertical"
            android:layout_weight="1.0"
            android:textColor="#666666"
            android:layout_marginLeft="10dip"
            android:paddingTop="10dip"
            android:background="@drawable/listview_item_change"
            android:paddingBottom="10dip"/>
    </LinearLayout>

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[Center]: /images/20220615/55436d8149a74e0a84dd5eb365e6c86b.png