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。