Android开发入门之采用ListView实现数据列表显示

再次用到上一篇写过的db工程，

activity_main.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/black"
android:orientation="vertical"
tools:context=".MainActivity" >

<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="5dp" >

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:text="@string/name"
android:textColor="@android:color/white"
android:textSize="16sp" />

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:text="@string/phone"
android:textColor="@android:color/white"
android:textSize="16sp" />

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:text="@string/amount"
android:textColor="@android:color/white"
android:textSize="16sp" />
</RelativeLayout>

<ListView
android:id="@+id/lv"
android:layout_width="match_parent"
android:layout_height="match_parent" />

</LinearLayout>

item.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/black"
android:padding="5dp" >

<TextView
android:id="@+id/tv_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:textColor="@android:color/white"
android:textSize="16sp" />

<TextView
android:id="@+id/tv_phone"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:textColor="@android:color/white"
android:textSize="16sp" />

<TextView
android:id="@+id/tv_amount"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:textColor="@android:color/white"
android:textSize="16sp" />

</RelativeLayout>

MainActivity.java:
package cn.leigo.db;

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

import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import cn.leigo.domain.Person;
import cn.leigo.service.PersonService;

public class MainActivity extends Activity {
private PersonService service;
private ListView lv;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

service = new PersonService(this);
lv = (ListView) findViewById(R.id.lv);

show();
}

private void show() {
}

}


1.利用SimpleAdapter绑定数据

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



2.利用SimpleCursorAdapter绑定数据,SimpleCursorAdapter绑定的数据中必须有一个名为"_id"的字段

private void show2() {
Cursor c = service.getScrollDataCursor(0, 20);
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.item, c, new String[]{"name", "phone", "amount"},
new int[]{R.id.tv_name, R.id.tv_phone, R.id.tv_amount});
lv.setAdapter(adapter);
}

/**
* 分页获取记录
*
* @param offset跳过前面多少条记录
* @param maxResult每页获取多少条记录
* @return
*/
public Cursor getScrollDataCursor(int offset, int maxResult) {
SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
Cursor cursor = db.rawQuery(
"SELECT personid as _id,name,phone,amount FROM person order by personid asc limit ?,?",
new String[] { offset + "", maxResult + "" });
return cursor;
}

3.利用自定义适配器绑定数据
// 自定义适配器
private void show3() {
List<Person> persons = service.getScrollData(0, 20);
PersonAdapter adapter = new PersonAdapter(this, persons);
lv.setAdapter(adapter);
}

package cn.leigo.adapter;

import java.util.List;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import cn.leigo.db.R;
import cn.leigo.domain.Person;

public class PersonAdapter extends BaseAdapter {
private List<Person> persons; // 绑定的数据
private LayoutInflater inflater;

public PersonAdapter(Context context, List<Person> persons) {
this.persons = persons;
inflater = LayoutInflater.from(context);
}

@Override
public int getCount() {
return persons.size();
}

@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) {
ViewHolder holder;
if (convertView == null) {
convertView = inflater.inflate(R.layout.item, null);

holder = new ViewHolder();
holder.nameView = (TextView) convertView.findViewById(R.id.tv_name);
holder.phoneView = (TextView) convertView
.findViewById(R.id.tv_phone);
holder.amountView = (TextView) convertView
.findViewById(R.id.tv_amount);

convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}

Person person = persons.get(position);
// 实现数据绑定
holder.nameView.setText(person.getName());
holder.phoneView.setText(person.getPhone());
holder.amountView.setText(person.getAmount() + "");
return convertView;
}

static class ViewHolder {
TextView nameView;
TextView phoneView;
TextView amountView;
}

}

监听ListView的点击事件：
实现AdapterView.OnItemClickListener接口，重写onItemClick()方法

@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
//1.SimpleAdapter
HashMap<String, Object> map = (HashMap<String, Object>)parent.getItemAtPosition(position);
String name = (String) map.get("name");
Toast.makeText(this, name, Toast.LENGTH_SHORT).show();
//2.SimpleCursorAdapter
//Cursor c = (Cursor)parent.getItemAtPosition(position);
//String name = c.getString(c.getColumnIndex("name"));
//Toast.makeText(this, name, Toast.LENGTH_SHORT).show();
//3自定义适配器
//Person person = (Person) parent.getItemAtPosition(position);
//Toast.makeText(this, person.getName(), Toast.LENGTH_SHORT).show();
}

parent.getItemAtPosition(position)

得到的类型由public Object getItem(int position) 返回的类型决定。