ListView实现城市快速索引功能

今天我们用ListView+自定义组件SlideBar来实现城市的快速索引(当然其他相似的功能也是一样的)，虽然网上已经有很多大神做出来了，也更加的丰富，但我还是做一个小demo来练习巩固一下，毕竟多动动手总没坏处是吧，哈哈，先看效果图吧

看了效果图后我们就开始实现吧，其实也是很简单的(卧槽，图怎么这么大  =。=)

先是我们的布局文件，整体非常简单的布局：

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="match_parent"    android:layout_height="match_parent">        <FrameLayout            android:id="@+id/city_loacal"            android:layout_width="match_parent"            android:layout_height="wrap_content">            <ListView                android:id="@+id/city_rv"                android:layout_width="match_parent"                android:layout_height="wrap_content"/>            <TextView                android:id="@+id/float_letter"                android:layout_width="80dp"                android:layout_height="80dp"                android:layout_gravity="center"                android:background="#dcdcdc"                android:gravity="center"                android:textSize="40sp"                android:visibility="gone" />            <com.cn.listviewsliderbar.SlideBar                android:id="@+id/slidebar"                android:layout_width="23dp"                android:background="#dcdcdc"                android:layout_height="wrap_content"                android:layout_gravity="right|bottom" />    </FrameLayout></LinearLayout>

布局就是这么简单，然后是我们的Activity的代码:

import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.ListView;import android.widget.TextView;/** */public class CityActivty extends Activity implements SlideBar.OnTouchLetterChangeListenner{    CityListAdapter mAdapter;    TextView float_letter;    ListView cityList;    SlideBar slideBar;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_city);        mAdapter = new CityListAdapter(this);        cityList= (ListView) findViewById(R.id.city_rv);        float_letter = (TextView) findViewById(R.id.float_letter);        slideBar= (SlideBar) findViewById(R.id.slidebar);//      cityRv.addHeaderView(v);        cityList.setAdapter(mAdapter);        slideBar.setOnTouchLetterChangeListenner(this);    }    @Override    public void onTouchLetterChange(boolean isTouched, String s) {        float_letter.setText(s);        if (isTouched) {            float_letter.setVisibility(View.VISIBLE);        } else {            float_letter.postDelayed(new Runnable() {                @Override                public void run() {                    float_letter.setVisibility(View.GONE);                }            }, 100);        }        int moveToPosition = mAdapter                .getPositionForSection(s.charAt(0));        if (moveToPosition >= 0) {            cityList.setSelectionFromTop(moveToPosition, 0);        }    }}

OnTouchLetterChangeListener是我们SlideBar里面定义的接口，是SlideBar的滑动与listView相关联的监听方法，我们通过实现它的方法onTouchLetterChange来调用ListView的setSelectionFromTop来完成索引功能。

下面是Adapter的代码：

import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.SectionIndexer;import android.widget.TextView;import java.util.ArrayList;import java.util.Collections;import java.util.Comparator;import java.util.List;import java.util.Locale;public class CityListAdapter extends BaseAdapter implements SectionIndexer{    Context context;    List<CityEntity> data=getCityList();    public CityListAdapter(Context context) {        this.context = context;    }    @Override    public int getCount() {        return data.size();    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        CityViewHolder_2 holder_2 = null;        if (convertView == null){                holder_2=new CityViewHolder_2();                convertView= LayoutInflater.from(context).inflate(R.layout.item_listview_city,null);                holder_2.word_tv= (TextView) convertView.findViewById(R.id.city_word_tv);                holder_2.city_tv= (TextView) convertView.findViewById(R.id.city_list_tv);                convertView.setTag(holder_2);        }else{                holder_2= (CityViewHolder_2) convertView.getTag();        }            holder_2.city_tv.setText(getCityList().get(position).getCityname());            holder_2.word_tv.setText(getFirstChar(getCityList().get(position).getWord()));            int section = getSectionForPosition(position);            int sectionPos = getPositionForSection(section);            if(position == sectionPos) {                holder_2.word_tv.setVisibility(View.VISIBLE);            } else {                holder_2.word_tv.setVisibility(View.GONE);            }        return convertView;    }    private String getFirstChar(String sortKey) {        return sortKey.substring(0, 1).toUpperCase(Locale.CHINA);    }    @Override    public Object[] getSections() {        return new Object[0];    }    @Override    public int getPositionForSection(int sectionIndex) {        int position = -1;        for (int i = 0; i < data.size(); i++) {            int currentChar = getSectionForPosition(i);            if(currentChar == sectionIndex) {                position = i;                break;            }        }        return position;    }    @Override    public int getSectionForPosition(int position) {        return data.get(position).getWord().toUpperCase(Locale.CHINA).charAt(0);    }    class CityViewHolder_2{        TextView word_tv,city_tv;    }    @Override    public Object getItem(int position) {        return null;    }    @Override    public long getItemId(int position) {        return position;    }    public List<CityEntity> getCityList(){        List<CityEntity> data=new ArrayList<CityEntity>();        data.add(new CityEntity("成都","chengdu"));        data.add(new CityEntity("成都","chengdu"));        data.add(new CityEntity("成都","chengdu"));        data.add(new CityEntity("成都","chengdu"));        data.add(new CityEntity("成都","chengdu"));        data.add(new CityEntity("郑州","zhengzhou"));        data.add(new CityEntity("郑州","zhengzhou"));        data.add(new CityEntity("郑州","zhengzhou"));        data.add(new CityEntity("金华","jinhua"));        data.add(new CityEntity("金华","jinhua"));        data.add(new CityEntity("成都","chengdu"));        data.add(new CityEntity("成都","chengdu"));        data.add(new CityEntity("金华","jinhua"));        data.add(new CityEntity("金华","jinhua"));        data.add(new CityEntity("金华","jinhua"));        data.add(new CityEntity("郑州","zhengzhou"));        data.add(new CityEntity("郑州","zhengzhou"));        data.add(new CityEntity("郑州","zhengzhou"));        data.add(new CityEntity("郑州","zhengzhou"));        data.add(new CityEntity("郑州","zhengzhou"));        data.add(new CityEntity("金华","jinhua"));        data.add(new CityEntity("金华","jinhua"));        data.add(new CityEntity("成都","chengdu"));        data.add(new CityEntity("成都","chengdu"));        data.add(new CityEntity("成都","chengdu"));        data.add(new CityEntity("郑州","zhengzhou"));        data.add(new CityEntity("郑州","zhengzhou"));        data.add(new CityEntity("金华","jinhua"));        data.add(new CityEntity("金华","jinhua"));        data.add(new CityEntity("金华","jinhua"));        Collections.sort(data, new Comparator<CityEntity>() {            @Override            public int compare(CityEntity lhs, CityEntity rhs) {                return lhs.getWord().compareTo(rhs.getWord());            }        });        return data;    }}

这个里面的重点是SectionIndexer这个接口，我们一般的索引都会用到这个接口，这个接口它主要实现了两个方法是：getSectionForPosition()和getPositionForSection() ，前者是根据位置找索引号，后者是根据索引号找位置，具体的不同大家可以参考一下博客：http://blog.csdn.net/jack_l1/article/details/14165291

到这里我们这个功能的具体实现就这么多了，因为功能还是比较单一的，所以代码量也不是很多，SlideBar的代码会和源码一起给大家o(^▽^)o

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源码下载地址：http://download.csdn.net/detail/tobestrong_csdn/9594317