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);