实例讲解Android app开发中ListView的基本使用及优化

 <ListView
    android:id="@+id/listView1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" 
    android:divider="#33000000"
    android:dividerHeight="0.2dp"
    android:footerDividersEnabled="true"
    android:headerDividersEnabled="true"
    android:entries="@arrary/ctype">
  </ListView>

<resources>
<item >情景模式1</item>
<item >情景模式2</item> 
<item >情景模式3</item>
</resources>

listview = (ListView) findViewById(R.id.listView1);
 ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,R.array.ctype, android.R.layout.simple_list_item_checked);
    listview.setAdapter(adapter);

public class ActivityMain extends ListActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    String[] ctype ={"1","2","3"}; 
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,ctype);
    setListAdapter(adapter);

  }

  @Override
  protected void onListItemClick(ListView l, View v, int position, long id) {

    super.onListItemClick(l, v, position, id);
  }


}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="horizontal"
 android:layout_width="match_parent"
 android:layout_height="match_parent">
<ImageView 
  android:id="@+id/image" 
  android:paddingRight="10px"
  android:paddingTop="20px"
  android:paddingBottom="20px"
  android:adjustViewBounds="true"
  android:maxWidth="72px"
  android:maxHeight="72px"
  android:layout_height="wrap_content" 
  android:layout_width="wrap_content"/> 
 <TextView 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" 
  android:padding="10px"
  android:layout_gravity="center"
  android:id="@+id/title"
  />   
</LinearLayout>

public class MainActivity extends Activity {
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    ListView listview = (ListView) findViewById(R.id.listView1); // 获取列表视图
    int[] imageId = new int[] { R.drawable.img01, R.drawable.img02,
        R.drawable.img03, R.drawable.img04, R.drawable.img05,
        R.drawable.img06, R.drawable.img07, R.drawable.img08 }; // 定义并初始化保存图片id的数组
    String[] title = new String[] { "保密设置", "安全", "系统设置", "上网", "我的文档",
        "GPS导航", "我的音乐", "E-mail" }; // 定义并初始化保存列表项文字的数组
    List<Map<String, Object>> listItems = new ArrayList<Map<String, Object>>(); // 创建一个list集合
    // 通过for循环将图片id和列表项文字放到Map中，并添加到list集合中
    for (int i = 0; i < imageId.length; i++) {
      Map<String, Object> map = new HashMap<String, Object>(); // 实例化Map对象
      map.put("image", imageId[i]);
      map.put("title", title[i]);
      listItems.add(map); // 将map对象添加到List集合中
    }

    SimpleAdapter adapter = new SimpleAdapter(this, listItems,
        R.layout.items, new String[] { "title", "image" }, new int[] {
            R.id.title, R.id.image }); // 创建SimpleAdapter
    listview.setAdapter(adapter); // 将适配器与ListView关联

  }
}

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

  <ImageView
    android:id="@+id/imageView1"
     android:layout_width="50dip"
    android:layout_height="50dip"
    android:layout_marginLeft="5dip"
    android:layout_marginTop="5dip"
    android:layout_marginBottom="5dip"  
    android:src="@android:drawable/ic_lock_power_off" />

  <TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/textView2"
    android:layout_toRightOf="@+id/imageView1"
    android:text="name"
    android:textColor="#000000"
    android:textSize="20sp" />

  <TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/imageView1"
    android:layout_toRightOf="@+id/imageView1"
    android:text="number"
    android:textColor="#000000"
    android:textSize="20sp" />


</RelativeLayout>

public class MainActivity extends Activity {
  private ListView lv;
  private List<MyInfo> infos;
  private Random random;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    lv = (ListView) findViewById(R.id.listView1);
    infos = new ArrayList<MyInfo>();
//通过for循环将name和number添加到List集合中
    for (int i = 0; i < 100; i++) {
      MyInfo userInfo = new MyInfo();
      userInfo.setName("name"+i);
      userInfo.setNumber("number"+i);
      infos.add(userInfo);
      System.out.println(userInfo.toString());  
    }

    lv.setAdapter(new MyAdapter());
  }

  private class MyAdapter extends BaseAdapter{

    @Override
    public int getCount() {
      return infos.size();//返回listview的长度
    }
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
      MyInfo userInfo = infos.get(position);
      View view;
      ViewHolder holder;
      //减少内存中view对象创建的次数
      if (convertView != null && convertView instanceof RelativeLayout) {
        view = convertView;//复用已经回收掉的view对象
        holder = (ViewHolder) view.getTag();//得到他们的引用
      } else {
        view = View.inflate(getApplicationContext(),
            R.layout.item_layout, null);//把布局文件转化成View对象
        holder = new ViewHolder();
        //把ID存到存到holder对象中
        //注意是在view下findViewById
        holder.iv = (ImageView) view.findViewById(R.id.imageView1);
        holder.tv1 = (TextView) view.findViewById(R.id.textView1);
        holder.tv2 = (TextView) view.findViewById(R.id.textView2);
        view.setTag(holder);//对象创建出来时找到他们的引用存到holder中
      }
      holder.tv1.setText(infos.get(position).getName());
      holder.tv2.setText(infos.get(position).getNumber());
      return view;
    }
    @Override
    public Object getItem(int position) {      
      return null;
    }

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

  }
  /*
   * view对象的容器记录View对象的内存地址相当于一个记事本
   */
  static class ViewHolder{
    TextView tv1;
    TextView tv2;
    ImageView iv;
  }

}
public class MyInfo {
  private String name; 
  private String number;//也可以添加Bitmap

  @Override
  public String toString() {
    return "MyInfo [name=" + name + ", number=" + number + "]";
  }
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public String getNumber() {
    return number;
  }
  public void setNumber(String number) {
    this.number = number;
  }


}

holder.iv = (ImageView) view.findViewById(R.id.imageView1);