AdapterView及其子类之四：基于ListView及SimpleAdapter实现列表

代码请见SimpleAdapterDemo.zip。

步骤如下：

1、创建主布局文件

<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:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<ListView
android:id="@+id/listview"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:divider="#00ff00"
android:dividerHeight="2dp"
android:headerDividersEnabled="false"
/>

</RelativeLayout>

2、创建每个列表选项的视图

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/ll_listview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<ImageView
android:id="@+id/iv_header"
android:layout_width="0dp"
android:layout_height="40dp"
android:layout_weight="1"
android:contentDescription="@string/header"/>

<LinearLayout
android:id="@+id/ll_title_content"
android:layout_width="0dp"
android:layout_height="40dp"
android:orientation="vertical"
android:layout_weight="4">

<TextView
android:id="@+id/title"
android:layout_width="match_parent"
android:layout_height="20dp"
android:background="#000000" />

<TextView
android:id="@+id/content"
android:layout_width="match_parent"
android:layout_height="20dp"
android:background="#00ff00" />
</LinearLayout>

</LinearLayout>

3、创建主类

package com.ljh.listviewdemo;

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

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import android.app.Activity;

public class MainActivity extends Activity {

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

// （1）创建要显示的文本内容
String[] arr = { "header", "title", "content" };
// （2）与使用ListActivity的最大区别:使用findViewById得到一个ListView
ListView lv = (ListView) findViewById(R.id.listview);

// （3）创建ArrayAdapter，其中第二个参数resource：The resource ID for a layout file
// containing a TextView to use when instantiating views.是要以一个layout作为
// 参数，且此layout需要包含textview。
/*
* ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
* R.layout.list, arr);
*/

String[] titles = { "title1", "title2", "title3", "title4" };
String[] contents = { "content1", "content2", "content3", "content4" };
int[] headers = { R.drawable.p1, R.drawable.p2, R.drawable.p3,
R.drawable.p4 };
List<Map<String, Object>> datas = new ArrayList<Map<String, Object>>();

/*
* Parameters:
* context The context where the View associated with this
* SimpleAdapter is running data A List of Maps. Each entry in the List
* corresponds to one row in the list. The Maps contain the data for
* each row, and should include all the entries specified in "from"
* resource Resource identifier of a view layout that defines the views
* for this list item. The layout file should include at least those
* named views defined in "to" from A list of column names that will be
* added to the Map associated with each item. to The views that should
* display column in the "from" parameter. These should all be
* TextViews. The first N views in this list are given the values of the
* first N columns in the from parameter.
*/SimpleAdapter adapter = new SimpleAdapter(this, datas,
R.layout.list, arr, new int[] { R.id.iv_header, R.id.title,
R.id.content });
for (int i = 0; i < titles.length; i++) {
Map<String, Object> map = new HashMap<String, Object>();
map.put("title", titles[i]);
map.put("content", contents[i]);
map.put("header", headers[i]);
datas.add(map);
}
// （4）为ListActivity设置adapter.
lv.setAdapter(adapter);

lv.setOnItemClickListener(new OnItemClickListener() {

// 定义当某个选项被点击时的操作。
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Toast.makeText(MainActivity.this,
position + " item is clicked.", Toast.LENGTH_LONG)
.show();

}

});

}

}

1、使用SimpleAdapter与ArrayAdapter相比，它可以支持复杂的表项结构，而不只是单一的textview。
2、其创建过程的两个主要区别是：

（1）每个列表项的布局文件不一样

（2）创建SimpleAdapter的操作更为复杂，需要构建一个List<Map<String, Object>>。