android ListView列表显示数据

item.xml

 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="horizontal"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent">
  
  <TextView
  android:layout_width="120dp"
  android:textSize="22sp"
  android:layout_height="wrap_content"
  android:id="@+id/name"
  />
  
   <TextView
  android:layout_width="150dp"
   android:textSize="22sp"
  android:layout_height="wrap_content"
  android:id="@+id/phone"
  />
  
  <TextView
  android:layout_width="fill_parent"
   android:textSize="22sp"
  android:layout_height="wrap_content"
  android:id="@+id/amount"
  />
</LinearLayout>

MainActivity.java

 

public class MainActivity extends Activity {
    private ListView listView;
    private PersonService personService;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        personService = new PersonService(this);
        
        listView = (ListView) this.findViewById(R.id.listView);
        listView.setOnItemClickListener(new ItemClickListener());
        show2();
    }
    
    private final class ItemClickListener implements OnItemClickListener{
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            ListView lView = (ListView)parent;
            /* 自定义适配器
            Person person = (Person) lView.getItemAtPosition(position);
            Toast.makeText(getApplicationContext(), person.getId().toString(), 1).show();*/
            
            Cursor cursor = (Cursor) lView.getItemAtPosition(position);
            int personid = cursor.getInt(cursor.getColumnIndex("_id"));
            Toast.makeText(getApplicationContext(), personid+ "", 1).show();
        }
    }
    
    
    //自定义适配器

    private void show3() {
        List<Person> persons = personService.getScrollData(0, 20);
        PersonAdapter adapter = new PersonAdapter(this, persons, R.layout.item);
        listView.setAdapter(adapter);
    }

    private void show2() {
        //此适配器要求有一个字段为_id，不然会报错，解决方法两种，1、增加_id的字段 2、为字段指定别名
        Cursor cursor = personService.getCursorScrollData(0, 20);
        SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.item, cursor,
                new String[]{"name", "phone", "amount"}, new int[]{R.id.name, R.id.phone, R.id.amount});
        listView.setAdapter(adapter);
    }

    private void show() {
        List<Person> persons = personService.getScrollData(0, 20);
        List<HashMap<String, Object>> data = new ArrayList<HashMap<String,Object>>();
        for(Person person : persons){
            HashMap<String, Object> item = new HashMap<String, Object>();
            item.put("name", person.getName());
            item.put("phone", person.getPhone());
            item.put("amount", person.getAmount());
            item.put("id", person.getId());
            data.add(item);
        }
        SimpleAdapter adapter = new SimpleAdapter(this, data, R.layout.item,
                new String[]{"name", "phone", "amount"}, new int[]{R.id.name, R.id.phone, R.id.amount});
        
        listView.setAdapter(adapter);
        
    }
}

自定义适配器：

public class PersonAdapter extends BaseAdapter {
    private List<Person> persons;//在绑定的数据
    private int resource;//绑定的条目界面，item.xml
    private LayoutInflater inflater; //布局填充器，通过上下文得到
    
    public PersonAdapter(Context context, List<Person> persons, int resource) {
        this.persons = persons;
        this.resource = resource;
        inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override

    public int getCount() {
        return persons.size();//数据总数
    }

    @Override
    public Object getItem(int position) {
        return persons.get(position);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        TextView nameView = null;
        TextView phoneView = null;
        TextView amountView = null;
        //利用View的缓存
        if(convertView==null){
            convertView = inflater.inflate(resource, null);//生成条目界面对象
            nameView = (TextView) convertView.findViewById(R.id.name);
            phoneView = (TextView) convertView.findViewById(R.id.phone);
            amountView = (TextView) convertView.findViewById(R.id.amount);
            
            ViewCache cache = new ViewCache();
            cache.nameView = nameView;
            cache.phoneView = phoneView;
            cache.amountView = amountView;            
            convertView.setTag(cache);
        }else{
            ViewCache cache = (ViewCache) convertView.getTag();
            nameView = cache.nameView;
            phoneView = cache.phoneView;
            amountView = cache.amountView;
        }
        Person person = persons.get(position);
        //下面代码实现数据绑定
        nameView.setText(person.getName());
        phoneView.setText(person.getPhone());
        amountView.setText(person.getAmount().toString());
        
        return convertView;
    }
    
    private final class ViewCache{
        public TextView nameView;
        public TextView phoneView;
        public TextView amountView;
    }

}