实例教程八：采用ListView实现数据列表显示

不错的帖子：

分享一个Android火焰效果程序
http://www.eoeandroid.com/thread-210395-1-1.html

android 查询工具源代码
http://www.eoeandroid.com/thread-210365-1-1.html

Android在线音乐播放器
http://www.eoeandroid.com/thread-210352-1-1.html

-------------------正文--------------------------

原文链接：http://www.eoeandroid.com/thread-201372-1-1.html

继上一章的数据，继续添加内容
item.xml

<?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" >

<TextView
android:id="@+id/txtName"
android:layout_width="120dp"
android:layout_height="wrap_content"
android:text="xxxxx" />

<TextView
android:id="@+id/txtPhone"
android:layout_width="150dp"
android:layout_height="wrap_content"
android:text="xxxxx" />

<TextView
android:id="@+id/txtAmount"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="2000" />

</LinearLayout>

main.xml

<?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="vertical" >

<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">

<TextView
android:layout_width="120dp"
android:layout_height="wrap_content"
android:text="@string/name"/>

<TextView
android:layout_width="120dp"
android:layout_height="wrap_content"
android:text="@string/phone"/>

<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/amount"/>

</LinearLayout>

<ListView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/lstShow" />

</LinearLayout>

package cn.itcast.db;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import cn.itcast.domain.Person;
import cn.itcast.domain.PersonAdapter;
import cn.itcast.service.PersonService;
import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.SimpleCursorAdapter;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;

public class MainActivity extends Activity {
//在Android平台上，集成了一个嵌入式关系型数据库——SQLite
//SQLite3支持NULL、INTEGER、REAL(浮点数字)、TEXT(字符串文本)和BLOB(二进制对象)数据类型
//虽然它支持的类型只有5种，但实际上sqlite3也接受varchar(n)、char(n)、decimal(p, s)等数据
//只不过在运行或保存时会转成对应的五种数据类型
//SQLite最大的特点是你可以把各种类型的数据保存到任何字段中，而不用关心字段声明的数据类型是什么

private ListView lstShow;
private PersonService personService;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

personService = new PersonService(this);
lstShow = (ListView)this.findViewById(R.id.lstShow);
lstShow.setOnItemClickListener(new ItemClickListener());
//show();
//show2();
show3();
}

private final class ItemClickListener implements OnItemClickListener{
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {

ListView lView = (ListView)parent;
//和show()3配对
Person person = (Person)lView.getItemAtPosition(position);
Toast.makeText(getApplicationContext(), person.getId().toString(), 1).show();

//和show()2配对
Cursor cursor = (Cursor)lView.getItemAtPosition(position);
int personId = cursor.getInt(cursor.getColumnIndex("_id"));
Toast.makeText(getApplicationContext(), personId, 1).show();

//和show()配对
List<HashMap<String, Object>> hashMap = (List<HashMap<String, Object>>)lView.getItemAtPosition(position);
int Id = Integer.valueOf(hashMap.get(personId).get("personId").toString());
Toast.makeText(getApplicationContext(), Id, 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);
lstShow.setAdapter(adapter);
}

private void show2() {
Cursor cursor = personService.getCursorScrollData(0, 20);
SimpleCursorAdapter adapter =
new SimpleCursorAdapter(this, R.layout.item, cursor,
new String[]{"name", "phone", "amount"},
new int[]{R.id.txtName, R.id.txtPhone, R.id.txtAmount});
lstShow.setAdapter(adapter);

//直接运行会报错，原因是SimpleCursorAdapter要求结果集中必须包含_id字段
//修复方法：1.把数据库表中的主键名称personId改为_id
//2.处理查询后的结果集
}

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.txtName, R.id.txtPhone, R.id.txtAmount});
lstShow.setAdapter(adapter);
//listView内部操作过程
//{
//        int total = adapter.getCount(); //用于得到数据总数
//        int perpage = 7;
//        for (int i = 0; i < perpage; i++) {
//                View view = adapter.getView(i, convertView, parent); //用于得到条目对应的View
//                //显示条目
//        }
//}
}

}

package cn.itcast.domain;

import java.util.List;

import cn.itcast.db.R;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class PersonAdapter extends BaseAdapter {
private List<Person> persons; //绑定数据
private int resource; //绑定条目界面
private LayoutInflater inflater;

public PersonAdapter(Context context, List<Person> persons, int resouce){
this.persons = persons;
this.resource = resource;
inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

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

@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 txtName = null;
TextView txtPhone = null;
TextView txtAmount = null;
//这样提升性能
if(convertView == null){ //表明现在是第1页
inflater.inflate(resource, null); //生成条目界面对象

txtName = (TextView)convertView.findViewById(R.id.txtName);
txtPhone = (TextView)convertView.findViewById(R.id.txtPhone);
txtAmount = (TextView)convertView.findViewById(R.id.txtAmount);

ViewCache cache = new ViewCache();
cache.txtName = txtName;
cache.txtPhone = txtPhone;
cache.txtAmount = txtAmount;

convertView.setTag(cache);
}else{
ViewCache cache = (ViewCache)convertView.getTag();
txtName = cache.txtName;
txtPhone = cache.txtPhone;
txtAmount = cache.txtAmount;
}

Person person = persons.get(position);
//下面代码实现数据绑定
txtName.setText(person.getName());
txtPhone.setText(person.getPhone());
txtAmount.setText(person.getAmount().toString());

return null;
}

private final class ViewCache{
public TextView txtName;
public TextView txtPhone;
public TextView txtAmount;
}
}