Android ListView 适配器

　　ListView 的大体作用是填充数据和用户交互后产生的响应。其绑定数据方式多种，将最近学习的三种总结如下：

　　1、ListView 和ArrayAdapter

　　（1）建立一个常量类Constant，放置模拟数据

public final class Constant {
    //定义一个数组
    public static final String[] str = new String[]{"东部", "西部", "南部", "北部", "中部",
            "东南部", "西北部", "西南部", "东北部", "中西部", "中南部", "中北部", "其他部"};

    private static final String[] str_name = {"柠檬", "苹果", "土豆", "西红柿", "香蕉"};
    private static final String[] str_class = {"水果", "水果", "蔬菜", "蔬菜", "水果"};
    private static final String[] str_address = {"海南", "吉林", "河南", "广西", "广东"};

    //把数据放到list中
    public static List<HashMap<String, Object>> setList() {
        List<HashMap<String, Object>> list = new ArrayList<HashMap<String, Object>>();
        for (int i = 0; i < str_name.length; i++) {
            HashMap<String, Object> hashMap = new HashMap<String, Object>();
            hashMap.put("name", str_name[i]);
            hashMap.put("str_class", str_class[i]);
            hashMap.put("address", str_address[i]);

            list.add(hashMap);
        }
        return list;
    }

    public static String[] str_arr() {
        return str;
    }
}

　　（2）建立一个ListView的布局文件（activity_arrary.xml）

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context="com.yt.aboutlistview.activity.ArrayActivity">

    <TextView android:text="我是ArrayActivity"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textView2" />

    <ListView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/lv_arr"
        android:layout_below="@+id/textView2"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

</RelativeLayout>

　　（3）在布局对应的ArrayActivity.java中绑定适配器　

public class ArrayActivity extends Activity {
    private ListView lv;
    private String[] str = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
//        str = Constant.str_arr();
//        str = Constant.str;//如果数组公有也可以直接调用
        setContentView(R.layout.activity_array);
        //获取listview对象
        lv = (ListView) findViewById(R.id.lv_arr);
        //和适配器绑定
        lv.setAdapter(
                //ArrayAdapter中三个参数，第一个：上下文，第二个listview显示的样式，但三个listview内容
                new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,Constant.str_arr()));
        //监听事件
        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Toast.makeText(ArrayActivity.this,"第 "+i+ "行，值是 "+view.toString(),Toast.LENGTH_LONG).show();
            }
        });
    }
}

　　2、Listview 和SimpleAdapter（本例和下例都要引用1-（1）中的数据）

　　（1）建立布局文件activity_simple.xml(布局文件差不多，看具体使用)

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context="com.yt.aboutlistview.activity.SimpleActivity">

    <TextView android:text="SimpleAdapter"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textView3" />

    <ListView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/lv_simple"
        android:layout_below="@+id/textView3"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="45dp" />

</RelativeLayout>

　　（2）ListView的属性文件activity_simple_item.xml

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

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="tv_sim_item_name"
        android:id="@+id/tv_sim_item_name"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:textSize="20dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="tv_sim_item_class"
        android:id="@+id/tv_sim_item_class"
        android:layout_alignParentTop="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:textSize="30dp"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="New Text"
        android:id="@+id/tv_sim_item_address"
        android:layout_below="@+id/tv_sim_item_name"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:textSize="15dp"/>
</RelativeLayout>

　　（3）在布局对应的SimpleActivity.java绑定适配器

public class SimpleActivity extends Activity {
    private ListView lv;
    List<HashMap<String,Object>> list = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_simple);

        lv = (ListView) findViewById(R.id.lv_simple);
        //构造一个数组
        list = Constant.setList();
        SimpleAdapter adapter = new SimpleAdapter(this//上下文
                ,list//需要显示的数据
                ,R.layout.activity_simple_item  //用来显示的布局
                , new String[]{"name","str_class","address"}//将数据映射到空间中去
                ,new int[]{R.id.tv_sim_item_name,R.id.tv_sim_item_class,R.id.tv_sim_item_address}
        );

        //绑定数据源
        lv.setAdapter(adapter);
        //监听事件
        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Toast.makeText(SimpleActivity.this, "第 " + i+1 + "行，值是 " + view.toString(), Toast.LENGTH_LONG).show();
            }
        });
    }
}

　　3、通用的基础适配器BaseAdapter，直接用2的布局，

　　(1) 定义一个适配器MyAdapter.java

public class Myadapter extends BaseAdapter {
    private Context context;
    private List<HashMap<String,Object>> list;
    public Myadapter(Context context,List<HashMap<String,Object>> list){
        this.context = context;
        this.list = list;
    }

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

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

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

    @Override
    public View getView(final int position, View view, ViewGroup viewGroup) {
        ViewHoder hoder = null;
        if(view == null){
            view = View.inflate(context,R.layout.activity_simple_item,null);
            hoder = new ViewHoder();

            hoder.name = (TextView) view.findViewById(R.id.tv_sim_item_name);
            hoder.str_class = (TextView) view.findViewById(R.id.tv_sim_item_class);
            hoder.address = (TextView) view.findViewById(R.id.tv_sim_item_address);
            //绑定ViewHolder对象
            view.setTag(hoder);
        }else {
            hoder = (ViewHoder) view.getTag();
        }
        hoder.name.setText(list.get(position).get("name").toString());
        hoder.str_class.setText(list.get(position).get("str_class").toString());
        hoder.address.setText(list.get(position).get("address").toString());
        hoder.str_class.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(context, "第 " + position + "行，name：" + list.get(position).get("name").toString(), Toast.LENGTH_SHORT).show();
            }
        });
        return view;
    }

    public final class ViewHoder{
        public TextView name;
        public TextView str_class;
        public TextView address;
    }
}

　　（2）Activity文件和Adapter进行绑定

public class MyAdapterActivity extends Activity {
    private ListView lv ;
    private List<HashMap<String,Object>> list;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_simple);//和simple共用
        //setContentView(R.layout.activity_my_adapter);
        list = Constant.setList();
        lv = (ListView) findViewById(R.id.lv_simple);
        Myadapter myadapter = new Myadapter(this, list);
        lv.setAdapter(myadapter);
        //如果需要下面可用，需要在activity_simple_item.xml把控件焦点置为失焦
//        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
//            @Override
//            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
//                Log.i("","第 "+i+"行，name："+list.get(i+1).get("name").toString());
//            }
//        });
    }
}

　　都说岁月是一把杀猪刀，美好的一天即将又要开始了，明天还要上班，写得比较简单，主要是为了帮助本人学习记忆，如果对你也有用处，那更好，如果有不明白之处，欢迎留言。如果发现有错误，不管大神和小神路过，请告诉我，以便及时改过，愿我们每天都进步一点点。