2.1.3常用组件2

1、2.1.2 常用组件2,By wqwen,ListView,2,ListView是大量数据展示的常用组件。 ListView利用包含以下两个部分：,ListView组件 ListView的数据（Adapter),最简单的ListView例子,3,public class MyListActivity extends ListActivity public void onCreate(Bundle bundle) super.onCreate(bundle); String names = new String “北京”, “上海”, “天津”, “重庆”, “广东”, “广西”, “湖南”,

2、“湖北”; this.setListAdapter(new ArrayAdapter(this, android.R.layout.simple_list_item_1, names); Override protected void onListItemClick(ListView l, View v, int position, long id) super.onListItemClick(l, v, position, id); Object obj = this.getListAdapter().getItem(position); String keyword = obj.toStr

3、ing(); Toast.makeText(this, “你选择的是: + keyword, Toast.LENGTH_LONG).show(); ,自定义ListView,4,ListView可以通过自定义的布局，实现更加丰富，更加实用的列表示图,创建Activity类 创建Activity布局文件 创建ListView中条目的布局文件 编写代码,主界面布局文件,5, ,ListView行布局,6, ,添加图片素材,7,在res目录下新建一个drawable目录，然后把图片复制到此目录 下,Activity类概述,8,制造商的类,ListView的适配器类,Activity类,Activit

4、y主类,9,public class ATListViewCustomDemoActivity extends Activity Override public void onCreate(Bundle savedInstanceState) super.onCreate(savedInstanceState); setContentView(R.layout.main); ListView listView=(ListView)findViewById(R.id.lvCar); CarAdapter carAdapter = new CarAdapter(); List list = get

5、CarList(); carAdapter.setList(list); listView.setAdapter(carAdapter); ,创建适配器实例,设置适配器,内部类1对象类,10,此对象类用于存储ListView中每一行的信息,内部类2适配器类1,11,适配器类用于实现自定义的ListView视图 class CarAdapter extends BaseAdapter private List list = null; private LayoutInflater mInflater=null; class ViewHolder TextView text; ImageView

6、icon; private LayoutInflater getInflater () if(mInflater=null) mInflater= (LayoutInflater)getSystemService(LAYOUT_INFLATER_SERVICE); return mInflater; ,此内部类用于存放ListView的UI视图组件,内部类2适配器类2,12,Override public int getCount() return list.size(); public void setList(List list) this.list = list; Override pu

7、blic Object getItem(int position) return list.get(position); Override public long getItemId(int position) return position; ,内部类2适配器类3,13,Override public View getView(int position, View convertView, ViewGroup parent) ViewHolder holder; CarManufacturer model=list.get(position); if (convertView = null) mInflater=getInflater(); convertView = mInflater.inflate(R.layout.view,null); holder = new ViewHolder(); holder.text = (TextView) convertView.findViewById(R.id.tvName); holder.icon = (ImageView) convertView.findViewById(R.id.imgIcon); convertView.setTag(holder); else holder = (ViewHolder) convert