Android学习 —— 多种适配器方式实现ListView

笔记摘要：

本文主要对ListView列表显示的实现进行了分析，对于列表显示，分为两个部分，第一个部分是整体布局，也就是ListView所在的布局，但ListView中的一个个横条Item布局也需要我们自己去构建，所以需要创建一个Item的布局文件，然后通过配置器来引入，当然也引入一些数据，最后为ListView设置适配器即可。适配器有多种，这里就介绍了几种不同的适配器：ArrayAdapter、SimpleAdapter、CursorAdapter、以及自定义的Adapter。

ArrayAdapter

ArrayAdapter的使用比较简单，只需为ListView设置ArrayAdapter，然后传入要显示的内容即可。由名字也可以看出，是一个类似于数组的形式，所以条目都统一了样式，

比较单一，传值也比较简便。



main.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"
tools:context=".MainActivity" >

<ListView
android:id="@+id/lv"
android:layout_width="match_parent"
android:layout_height="match_parent" />

</RelativeLayout>

条目显示布局：listview_item.xml

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

<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/btn_rating_star_on_normal_holo_light" />

<TextView
android:id="@+id/tv_content"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="我是文本"
android:textSize="24sp" />

</LinearLayout>

MainActivity

import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class MainActivity extends Activity {
ListView lv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

lv = (ListView) findViewById(R.id.listView_id);
lv.setAdapter(new ArrayAdapter(this,R.layout.listview_item, R.id.tv_content,new String[]{"功能1","功能2","功能3"}));
}
}

SimpleAdatper

构造函数：

SimpleAdapter(Context context, List<? extends Map<String, ?>> data, int resource, String[] from, int[] to)

由SimpleAdapter的构造函数列表可以看出，

List<? extends Map<String, ?>>需要一个存储Map集合的List集合，来提供数据

int resource：一个布局文件来提供页面布局

From：A list of column names that will be added to the Map associated with each item.，需要适配数据的列名，其与Map集合的键相对应。

To : The views that should display column in the "from" parameter. These should all be TextViews. 与From相对应的TextView的资源ID



整体布局文件Main.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"
tools:context=".MainActivity" >

<TextView

android:id="@+id/info_textView"
android:text="产品详细信息"
android:textSize="25sp"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<ListView
android:layout_below="@id/info_textView"
android:id="@+id/listView_id"
android:layout_width="match_parent"
android:layout_height="match_parent"
></ListView>
</RelativeLayout>

条目的布局文件listView_item.xml

<?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="horizontal" >

<TextView
android:id="@+id/model_textView"
android:text="型号"
android:textSize="20sp"
android:gravity="center_horizontal"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
<TextView
android:text="颜色"
android:textSize="20sp"
android:gravity="center_horizontal"
android:layout_weight="1"
android:id="@+id/color_textView"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
<TextView
android:text="大小"
android:textSize="20sp"
android:layout_weight="1"
android:gravity="center_horizontal"
android:id="@+id/size_textView"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>

</LinearLayout>

MainActivity

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class MainActivity extends Activity {
private ListView listView;
private List<Map<String,String>> data ;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.listView_id);

Map<String,String> itemdata1 = new HashMap<String,String>();
itemdata1.put("型号","复古");
itemdata1.put("颜色","浅灰");
itemdata1.put("大小","Large");

Map<String,String> itemdata2 = new HashMap<String,String>();
itemdata2.put("型号","时尚");
itemdata2.put("颜色","紫金");
itemdata2.put("大小","small");

data = new ArrayList<Map<String,String>>();
data.add(itemdata1);
data.add(itemdata2);

//SimpleAdapter(Context context, List<? extends Map<String,?>> data, int resource, String[] from, int[] to)
//context,上下文
//List<? extends Map<String, ?>> data,提供要显示的数据
//int resource,一个布局文件来提供页面布局
//String[] from, 需要适配数据的列名，其与Map集合的键相对应。
//int[] to 与from相对应的显示视图，必须都是TextView，通过R.id.TextView来引入
listView.setAdapter(new SimpleAdapter(this, data, R.layout.listview_item, new String[]{"颜色","型号","大小"},
new int[]{R.id.model_textView,R.id.color_textView,R.id.size_textView}));
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}

}

CursorAdapter

注意：

在使用CursorAdapter为Listview适配的时候，Sqlite标准要求cursor必须有一个属性 "_id"，否则就无法使用

在使用SimpleCursorAdapter时，有一个相同的方法已经过时，对于这样的处理，为了向下兼容，我们可以将低版本和高版本的方法都提供出 去，只需对用户的版本进行判断调用响应的方法即可



总体布局文件

<LinearLayout
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:orientation="vertical"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<TextView
android:text="姓名"
android:textSize="23sp"
android:id="@+id/name_textView"
android:layout_weight="1"
android:layout_gravity="center_horizontal"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<TextView
android:text="电话"
android:textSize="23sp"
android:id="@+id/phone_textView"
android:layout_weight="1"
android:gravity="center"
android:layout_gravity="center_horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<TextView
android:text="收入"
android:textSize="23sp"
android:id="@+id/money_textView"
android:layout_weight="1"
android:gravity="center"
android:layout_gravity="center_horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>

<ListView
android:id="@+id/listView_id"
android:layout_width="match_parent"
android:layout_height="match_parent"
></ListView>

</LinearLayout>

条目布局文件

<?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="horizontal" >

<TextView
android:text="姓名"
android:id="@+id/name_textView"
android:textSize="20sp"
android:layout_weight="1"
android:layout_gravity="center_horizontal"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<TextView
android:text="电话"
android:id="@+id/phone_textView"
android:textSize="20sp"
android:layout_weight="1"
android:gravity="center"
android:layout_gravity="center_horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<TextView
android:text="收入"
android:id="@+id/money_textView"
android:textSize="20sp"
android:layout_weight="1"
android:gravity="center"
android:layout_gravity="center_horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>

MainActivity

import android.app.Activity;
import android.database.Cursor;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.widget.CursorAdapter;
import android.support.v4.widget.SimpleCursorAdapter;
import android.util.Log;
import android.webkit.WebChromeClient.CustomViewCallback;
import android.widget.LinearLayout;
import android.widget.ListView;

import com.itheima.db.dao.PersonDao2;

public class MainActivity extends Activity {
private static final String TAG = "MainActivity";
private ListView listView;

@SuppressWarnings("deprecation")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.listView_id);

/*PersonDBOpenHelper helper = new PersonDBOpenHelper(this);
helper.getWritableDatabase();*/

PersonDao dao = new PersonDao(this);
Cursor cursor = dao.findAllCursor();//查询所有的记录并返回Cursor
while(cursor.moveToNext()){
int id = cursor.getInt(cursor.getColumnIndex("_id"));
String name = cursor.getString(cursor.getColumnIndex("name"));
String phone = cursor.getString(cursor.getColumnIndex("phone"));
int money = cursor.getInt(cursor.getColumnIndex("money"));
Log.i(TAG,id+" name: "+name+" phone: "+phone+" money: "+money);
}

//(Context context, int layout, Cursor c, String[] from, int[] to)
if (Build.VERSION.SDK_INT >= 11) {
// api 11以上才可以运行
listView.setAdapter(new SimpleCursorAdapter(
this,
R.layout.list_item,
cursor,
new String[] { "name", "phone", "money" },
new int[] {R.id.name_textView, R.id.phone_textView, R.id.money_textView },
0));
Log.i(TAG,"我是高版本api");
} else {

// api 11 以下运行
listView.setAdapter(new SimpleCursorAdapter(this,
R.layout.list_item,
cursor,
new String[] { "name", "phone", "money" },
new int[] {R.id.name_textView, R.id.phone_textView, R.id.money_textView }));

Log.i(TAG,"我是低版本api");
}

}
}

自定义Adapter：继承BaseAdapter

整体布局文件：Main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="match_parent"
tools:context=".MainActivity" >

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">

<TextView
android:text="ID"
android:layout_weight="1"
android:textSize="18sp"
android:gravity="center_horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<TextView
android:text="姓名"
android:layout_weight="1"
android:textSize="18sp"
android:gravity="center_horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<TextView
android:text="电话"
android:layout_weight="1"
android:textSize="18sp"
android:gravity="center_horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<TextView
android:text="收入"
android:textSize="18sp"
android:layout_weight="1"
android:gravity="center_horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
</LinearLayout>

<ListView
android:id="@+id/lv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>

</LinearLayout>

Item布局文件

<?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="horizontal" >

<TextView
android:id="@+id/id_TextView"
android:text="ID"
android:gravity="center_horizontal"
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="1"
android:textSize="16sp"
/>

<TextView
android:id="@+id/name_TextView"
android:text="姓名"
android:layout_weight="1"
android:gravity="center_horizontal"
android:layout_width="0dip"
android:layout_height="match_parent"
android:textSize="16sp"
/>
<TextView
android:id="@+id/phone_TextView"
android:text="电话"
android:layout_weight="1"
android:gravity="center_horizontal"
android:layout_width="0dip"
android:layout_height="match_parent"
android:textSize="16sp"
/>
<TextView
android:id="@+id/amount_TextView"
android:text="收入"
android:layout_weight="1"
android:gravity="center_horizontal"
android:layout_width="0dip"
android:layout_height="match_parent"
android:textSize="16sp"
/>
</LinearLayout>

MainActivity

public class MainActivity extends Activity {
private static final String TAG = "MainActivity";
private List<Person> persons ;
private PersonDao dao;
private ListView lv ;
ListAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv = (ListView) findViewById(R.id.lv);
dao = new PersonDao(this);
persons = dao.findAll();

adapter = new ListAdapter();
Log.i(TAG,adapter.getCount()+"");
lv.setAdapter(adapter);//为ListView 设置适配器，适配器中已经将数据填充到了布局中

//为ListView设置点击事件
lv.setOnItemClickListener(new OnItemClickListener() {

@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Person person = persons.get(position);
String name = person.getName();
int personid = person.getId();
//Toast.makeText(MainActivity.this, personid, 1).show();
Toast.makeText(MainActivity.this, "id:"+personid, 1).show();
}
});

//为ListView设置长按监听：删除一条数据
lv.setOnItemLongClickListener(new OnItemLongClickListener() {

@Override
public boolean onItemLongClick(AdapterView<?> parent, View view,
int position, long id) {
Person person = persons.get(position);
int personid = person.getId();
dao.delete(personid);//从数据库中将数据删除
persons.remove(position);//从适配器中删除
adapter.notifyDataSetChanged();//通知数据适配器 更新界面

return true;//false 当前的事件 不会被消费掉,继续执行，OnItemClickListener会Toaster
//true 当前事件执行到这里 就终止了，后面的不再执行，
//比如setOnItemClickListener的Toaster就不执行
}});

}

自定义的Adapter类：继承BaseAdapter

private final class ListAdapter extends BaseAdapter{

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

@Override
public Object getItem(int position) {
return null;
}

@Override
public long getItemId(int position) {
return 0;
}

//返回当前位置对应的view对象，显示内容
@Override
public View getView(int position, View convertView, ViewGroup parent) {
//position代表位置

//通过View关联自定义Item布局，进行填充
View view = View.inflate(MainActivity.this, R.layout.list_item, null);

//获取指定位置的对象
Person person = persons.get(position);

//获取要显示的组件,注意findViewById的调用对象是上面填充了Item的布局的对象View
TextView id_TextView = (TextView)view.findViewById(R.id.id_TextView);
TextView name_TextView = (TextView)view.findViewById(R.id.name_TextView);
TextView amount_TextView =(TextView)view.findViewById(R.id.amount_TextView);
TextView phone_TextView =(TextView)view.findViewById(R.id.phone_TextView);

id_TextView.setText(person.getId()+"");
name_TextView.setText(person.getName());
amount_TextView.setText(person.getAmount()+"");
phone_TextView.setText(person.getPhone());

return view;
}
}
}

工具类：查询所有的记录，这里省略了数据库

public List<Person> findAll(){
List<Person> persons = new ArrayList<Person>();
SQLiteDatabase db = helper.getReadableDatabase();
//query(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit)

Cursor cursor = db.query("person", new String[]{"id","name","phone","amount"}, null, null, null, null, null, null);
while(cursor.moveToNext()){
int id = cursor.getInt(cursor.getColumnIndex("id"));
String name = cursor.getString(cursor.getColumnIndex("name"));
String phone = cursor.getString(cursor.getColumnIndex("phone"));
String amount = cursor.getString(cursor.getColumnIndex("amount"));
persons.add(new Person(id,name,phone,Float.valueOf(amount)));
}
cursor.close();//关闭游标
db.close();//关闭数据库
return persons;
}