Android adapter设计模式一 静态设值

1、创建实体类：

/**
 * @描述 TODO
 * @项目名称 App_imooc
 * @包名 com.android.imooc.quickIndex
 * @类名 Person
 * @author chenlin
 * @date 2015年5月24日 下午10:09:25
 * @version 1.0
 */

public class Person implements Comparable<Person>{

    private String name;
    private String pinyin;

    public Person(String name){
        this.name = name;
        this.pinyin = PinyinUtils.getPinyin(name);
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPinyin() {
        return pinyin;
    }

    public void setPinyin(String pinyin) {
        this.pinyin = pinyin;
    }

    @Override
    public int compareTo(Person another) {
        return this.pinyin.compareTo(another.pinyin);
    }

}

2.创建适配器

/**
 * 
 * @描述         TODO
 * @项目名称      App_imooc
 * @包名         com.android.imooc.quickIndex
 * @类名         PersonAdapter
 * @author      chenlin
 * @date        2015年5月24日 下午10:37:07
 * @version     1.0
 */
public class PersonAdapter extends BaseAdapter {

    private Context mContext;
    private ArrayList<Person> mDatas;

    public PersonAdapter(Context mContext, ArrayList<Person> datas) {
        this.mContext = mContext;
        this.mDatas = datas;
    }

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

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        View view = convertView;
        if(convertView == null){
            view = view.inflate(mContext, R.layout.item_quickindex, null);
        }
        ViewHolder mViewHolder = ViewHolder.getHolder(view);

        Person p = mDatas.get(position);

        String str = null;
        String currentLetter = p.getPinyin().charAt(0) + "";
        // 根据上一个首字母,决定当前是否显示字母
        if(position == 0){
            str = currentLetter;
        }else {
            // 上一个人的拼音的首字母
            String preLetter = mDatas.get(position - 1).getPinyin().charAt(0) + "";
            if(!TextUtils.equals(preLetter, currentLetter)){
                str = currentLetter;
            }
        }

        // 根据str是否为空,决定是否显示索引栏
        mViewHolder.mIndex.setVisibility(str == null ? View.GONE : View.VISIBLE);
        mViewHolder.mIndex.setText(currentLetter);
        mViewHolder.mName.setText(p.getName());

        return view;
    }

    static class ViewHolder {
        TextView mIndex;
        TextView mName;

        public static ViewHolder getHolder(View view) {
            Object tag = view.getTag();
            if(tag != null){
                return (ViewHolder)tag;
            }else {
                ViewHolder viewHolder = new ViewHolder();
                viewHolder.mIndex = (TextView) view.findViewById(R.id.tv_index);
                viewHolder.mName = (TextView) view.findViewById(R.id.tv_name);
                view.setTag(viewHolder);
                return viewHolder;
            }
        }

    }

}

3.相关布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/tv_index"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:background="#888888"
        android:gravity="center_vertical"
        android:paddingLeft="20dp"
        android:text="A"
        android:textColor="#ffffff"
        android:textSize="20sp" />

    <TextView
        android:id="@+id/tv_name"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:gravity="center_vertical"
        android:paddingLeft="20dp"
        android:text="宋江"
        android:textSize="24sp" />

</LinearLayout>