SimpleAdapter ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
SimpleAdapter是扩展性最好的适配器，可以定义各种你想要的布局，而且使用很方便
SimpleAdapter(Context?context,?List<??extends?Map<String,??>> data, int resource,?String[]?from, int[] to)
参数context：上下文，比如this。关联SimpleAdapter运行的视图上下文
参数data：Map列表，列表要显示的数据，这部分需要自己实现，如例子中的getData()，类型要与上面的一致，每条项目要与from中指定条目一致
参数resource：ListView单项布局文件的Id,这个布局就是你自定义的布局了，你想显示什么样子的布局都在这个布局中。这个布局中必须包括了to中定义的控件id
参数 from：一个被添加到Map上关联每一个项目列名称的列表，数组里面是列名称
参数 to：是一个int数组，数组里面的id是自定义布局中各个控件的id，需要与上面的from对应
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SimpleAdapter可以使用自定义的ListView，然后setContentView即可。也可以直接使用系统自带的ListAcitivity，该ListActivity实现了ListView，显示ListView的时候做了很多优化。
ListActivity直接extends ListActivity即可，不需要在setContentView了
例子一：自定义布局，显示本地资源
如果直接继承ListAcitivty，则不需要自定义ListView，下面的是列表项单项显示格式
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?<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
??? android:layout_width="fill_parent"
??? android:layout_height="fill_parent"
??? android:orientation="horizontal" >
??? <ImageView
??????? android:id="@+id/img"
??????? android:layout_width="wrap_content"
??????? android:layout_height="wrap_content"
??????? android:layout_margin="3px"
??????? />
??? <LinearLayout
??????? android:layout_width="fill_parent"
??????? android:layout_height="wrap_content"
??????? android:orientation="vertical"
??????? >
??????? <TextView
??????????? android:id="@+id/title"
??????????? android:layout_width="fill_parent"
??????????? android:layout_height="wrap_content"
??????????? android:textSize="16sp"
??????????? />
??????? <TextView
??????????? android:id="@+id/info"
??????????? android:layout_width="fill_parent"
??????????? android:layout_height="wrap_content"
??????????? android:textSize="10sp"
??????????? />
??? </LinearLayout>
</LinearLayout>
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Activity
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package com.loulijun.demo13;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.ListActivity;
import android.os.Bundle;
import android.widget.SimpleAdapter;
public class Demo13Activity extends ListActivity {
??? /** Called when the activity is first created. */
??? @Override
??? public void onCreate(Bundle savedInstanceState) {
??????? super.onCreate(savedInstanceState);
??????? SimpleAdapter adapter = new SimpleAdapter(this, getData(),
??????????????? R.layout.main, new String[] { "img", "title", "info" },
??????????????? new int[] { R.id.img, R.id.title, R.id.info });
??????? setListAdapter(adapter);
??? }
??? private List<Map<String, Object>> getData() {
??????? List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
??????? Map<String, Object> map = new HashMap<String, Object>();
??????? map.put("img", R.drawable.e001);
??????? map.put("title", "小宗");
??????? map.put("info", "电台DJ");
??????? list.add(map);
??????? map = new HashMap<String, Object>();
??????? map.put("img", R.drawable.e002);
??????? map.put("title", "貂蝉");
??????? map.put("info", "四大美女");
??????? list.add(map);
??????? map = new HashMap<String, Object>();
??????? map.put("img", R.drawable.e04b);
??????? map.put("title", "奶茶");
??????? map.put("info", "清纯妹妹");
??????? list.add(map);
??????? map = new HashMap<String, Object>();
??????? map.put("img", R.drawable.e04e);
??????? map.put("title", "大黄");
??????? map.put("info", "是小狗");
??????? list.add(map);
??????? map = new HashMap<String, Object>();
??????? map.put("img", R.drawable.e11a);
??????? map.put("title", "hello");
??????? map.put("info", "every thing");
??????? list.add(map);
??????? map = new HashMap<String, Object>();
??????? map.put("img", R.drawable.e11d);
??????? map.put("title", "world");
??????? map.put("info", "hello world");
??????? list.add(map);
??????? return list;
??? }
}?
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注：自定义ListView也有其好处，因为继承的ListAcitivity布局的样子已经定了下来，但是如果我们需要在ListView中实现某些效果，比如快速滚动条，就需要自定义了。另外如果你继承的比如是TabActivity等其他
Acitivty的话，就不能继承ListAcitivty了，因为JAVA是单继承，这时候还是需要自定义的ListView
如果自定义ListView而不是继承ListActivity需要如下样子实现
mylist.xml，在ListView中可以定义其他属性
-----------------------------------------------------
<?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" >
??? <ListView
??????? android:id="@+id/listview"
??????? android:layout_width="fill_parent"
??????? android:layout_height="wrap_content"
??????? ></ListView>
-----------------------------------------------------
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如果使用自定义的ListView就需要在上面的代码修改一下下了，Acitivity其他部分都一样，区别在于灰色区域
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public class Demo13Activity extends Activity {
??? private ListView lv;
??? @Override
??? public void onCreate(Bundle savedInstanceState) {
??????? super.onCreate(savedInstanceState);
??????? setContentView(R.layout.mylist);
??????? lv = (ListView)findViewById(R.id.listview);
??????? SimpleAdapter adapter = new SimpleAdapter(this, getData(),
??????????????? R.layout.main, new String[] { "img", "title", "info" },
??????????????? new int[] { R.id.img, R.id.title, R.id.info });
??????? //setListAdapter(adapter);
??????? lv.setAdapter(adapter);
??? }
运行结果：
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|------------------------------------|
用户可以自定义布局，可以是线性布局，也可以是网格布局等等
接下来说说ViewBinder的使用，上面的例子中我们显示了本地资源，图片都是保存在本地的，但是用上面的方法显示网络上获取的图片却有问题，因为如果ListView要显示外部资源的话必须要设置ViewBinder，通过ViewBinder的绑定机制来显示网络资源，下面是个显示网络图片的例子（如果可能的话，最好还是使用BaseAdapter）
例子二：自定义布局，显示网络资源，ViewBinder的使用
由于需要访问网络资源，首先在你的清单文件中加入权限
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package com.loulijun.demo13;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.SimpleAdapter.ViewBinder;
public class Demo13Activity extends Activity {
??? private ListView lv;
??? private static final String iphoneUrl = "http://www.51aigoo.com/images/20100107/6b21df8c2419480e.jpg";
??? private static final String macbookproUrl = "http://www.esundigi.net/images/goods/20110317/6ece8f319694f0b1.jpg";
??? @Override
??? public void onCreate(Bundle savedInstanceState) {
??????? super.onCreate(savedInstanceState);
??????? setContentView(R.layout.mylist);
??????? lv = (ListView)findViewById(R.id.listview);
???
??????? SimpleAdapter adapter = new SimpleAdapter(
??????????????? this,
??????????????? getData(),
??????????????? R.layout.main,
??????????????? new String[] {"img","title","info"},
??????????????? new int[] { R.id.img, R.id.title, R.id.info});
??????? //setListAdapter(adapter);
??????? adapter.setViewBinder(new MyViewBinder());
??????? lv.setAdapter(adapter);
???????
??? }
??? //获取网络图片资源，返回类型是Bitmap，用于设置在ListView中
??? public Bitmap getBitmap(String httpUrl)
??? {
??????? Bitmap bmp = null;
??????? //ListView中获取网络图片
??????? try {
??????????? URL url = new URL(httpUrl);
??????????? HttpURLConnection conn = (HttpURLConnection)url.openConnection();
??????????? InputStream is = conn.getInputStream();
??????????? bmp = BitmapFactory.decodeStream(is);
??????? } catch (Exception e) {
??????????? // TODO Auto-generated catch block
??????????? e.printStackTrace();
??????? }
??????? return bmp;
??? }
??? //ListView上需要显示的数据
??? private List<Map<String, Object>> getData() {
??????? List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
??????? Map<String, Object> map = new HashMap<String, Object>();
??????? //设置绑定是数据是图片
??????? map.put("img", getBitmap(iphoneUrl));
??????? map.put("title", "iphone4");
??????? map.put("info", "可远观而买不起嫣");
??????? list.add(map);
???????
??????? map = new HashMap<String, Object>();
??????? map.put("img", getBitmap(macbookproUrl));
??????? map.put("title", "Macbook pro");
??????? map.put("info", "明年买个玩玩");
??????? list.add(map);
??????? return list;
??? }
}
//实现ViewBinder接口
class MyViewBinder implements ViewBinder
{
??? /**
???? * view：要板顶数据的视图
???? * data：要绑定到视图的数据
???? * textRepresentation：一个表示所支持数据的安全的字符串，结果是data.toString()或空字符串，但不能是Null
???? * 返回值：如果数据绑定到视图返回真，否则返回假
???? */
??? @Override
??? public boolean setViewValue(View view, Object data,
??????????? String textRepresentation) {
??????? if((view instanceof ImageView)&(data instanceof Bitmap))
??????? {
??????????? ImageView iv = (ImageView)view;
??????????? Bitmap bmp = (Bitmap)data;
??????????? iv.setImageBitmap(bmp);
??????????? return true;
??????? }
??????? return false;
??? }
???
???
}
运行结果：
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原文：http://www.cnblogs.com/loulijun/archive/2011/12/27/2303488.html