Jack_King007的专栏

上一篇地址

天气APP的实战（1）

创建表和包的结构

 

1.activity放所有与活动相关的包，以为自己忘记在配置文件注册

2.Db 放于数据库相关的代码  建立数据库 数据持久化操作

3.Model 其实就是实体类 

4.Receive 存放所有广播接收器相关的代码

5.Service  存放所有与服务相关的代码

6.Utils  大家都估计是最熟悉的包 放工具类的地方

 

首先 我们要获取省市县的数据 用数据库进行存储 所以先建数据库 其实 我对于数据库的语言，没有校对工具是很容易错的，所以呢，大家最好现在用SQLiteExpertPers工具去调试下再去COPY到代码中.

WeatherOpenHelper

package com.xiaoxin.Weather.db;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class WeatherOpenHelper extends SQLiteOpenHelper {
	
	/**
	 *  Province表建表语句
	 */
	public static final String CREATE_PROVINCE = "create table Province ("
				+ "id integer primary key autoincrement, " 
				+ "province_name text, "
				+ "province_code text)";
	/**
	 *  City表建表语句
	 */
	public static final String CREATE_CITY = "create table City ("
				+ "id integer primary key autoincrement, " 
				+ "city_name text, " 
				+ "city_code text, " 
				+ "province_id integer)";
	/**
	 *  County表建表语句
	 */
	public static final String CREATE_COUNTY = "create table County ("
				+ "id integer primary key autoincrement, " 
				+ "county_name text, " 
				+ "county_code text, " 
				+ "city_id integer)";

	public WeatherOpenHelper(Context context, String name, CursorFactory factory,
			int version) {
		super(context, name, factory, version);
	}

	@Override
	public void onCreate(SQLiteDatabase db) {
		db.execSQL(CREATE_PROVINCE);  // 创建Province表
		db.execSQL(CREATE_CITY);  // 创建City表
		db.execSQL(CREATE_COUNTY);  // 创建County表
	}

	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
	}

}

就是三个建表的语句 最后在oncreate中执行 很简单的

另外每一张表最好有一个实体类，以便于后期开发

城市类

package com.xiaoxin.Weather.model;

public class City {

	private int id;

	private String cityName;

	private String cityCode;

	private int provinceId;

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getCityName() {
		return cityName;
	}

	public void setCityName(String cityName) {
		this.cityName = cityName;
	}

	public String getCityCode() {
		return cityCode;
	}

	public void setCityCode(String cityCode) {
		this.cityCode = cityCode;
	}

	public int getProvinceId() {
		return provinceId;
	}

	public void setProvinceId(int provinceId) {
		this.provinceId = provinceId;
	}

}

县

package com.xiaoxin.Weather.model;

public class County {

	private int id;

	private String countyName;

	private String countyCode;

	private int cityId;

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getCountyName() {
		return countyName;
	}

	public void setCountyName(String countyName) {
		this.countyName = countyName;
	}

	public String getCountyCode() {
		return countyCode;
	}

	public void setCountyCode(String countyCode) {
		this.countyCode = countyCode;
	}

	public int getCityId() {
		return cityId;
	}

	public void setCityId(int cityId) {
		this.cityId = cityId;
	}
	
}

省

package com.xiaoxin.Weather.model;

public class Province {

	private int id;

	private String provinceName;

	private String provinceCode;

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getProvinceName() {
		return provinceName;
	}

	public void setProvinceName(String provinceName) {
		this.provinceName = provinceName;
	}

	public String getProvinceCode() {
		return provinceCode;
	}

	public void setProvinceCode(String provinceCode) {
		this.provinceCode = provinceCode;
	}

}

可以看出来，实体类的内容都非常简单，基本就是生成数据库表对应字段的get和set方法，接着还需要创建一个coolWeatherDB类 这个类中会把一些常用的数据库操作进行封装，以便于后期使用。

package com.xiaoxin.Weather.db;

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

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import com.xiaoxin.Weather.model.City;
import com.xiaoxin.Weather.model.County;
import com.xiaoxin.Weather.model.Province;

public class WeatherDB {

	/**
	 * 数据库名
	 */
	public static final String DB_NAME = "weather";

	/**
	 * 数据库版本
	 */
	public static final int VERSION = 1;

	private static WeatherDB coolWeatherDB;

	private SQLiteDatabase db;

	/**
	 * 将构造方法私有化
	 */
	private WeatherDB(Context context) {
		WeatherOpenHelper dbHelper = new WeatherOpenHelper(context,
				DB_NAME, null, VERSION);
		db = dbHelper.getWritableDatabase();
	}

	/**
	 * 获取CoolWeatherDB的实例。
	 */
	public synchronized static WeatherDB getInstance(Context context) {
		if (coolWeatherDB == null) {
			coolWeatherDB = new WeatherDB(context);
		}
		return coolWeatherDB;
	}

	/**
	 * 将Province实例存储到数据库。
	 */
	public void saveProvince(Province province) {
		if (province != null) {
			ContentValues values = new ContentValues();
			values.put("province_name", province.getProvinceName());
			values.put("province_code", province.getProvinceCode());
			db.insert("Province", null, values);
		}
	}

	/**
	 * 从数据库读取全国所有的省份信息。
	 */
	public List<Province> loadProvinces() {
		List<Province> list = new ArrayList<Province>();
		Cursor cursor = db
				.query("Province", null, null, null, null, null, null);
		if (cursor.moveToFirst()) {
			do {
				Province province = new Province();
				province.setId(cursor.getInt(cursor.getColumnIndex("id")));
				province.setProvinceName(cursor.getString(cursor
						.getColumnIndex("province_name")));
				province.setProvinceCode(cursor.getString(cursor
						.getColumnIndex("province_code")));
				list.add(province);
			} while (cursor.moveToNext());
		}
		return list;
	}

	/**
	 * 将City实例存储到数据库。
	 */
	public void saveCity(City city) {
		if (city != null) {
			ContentValues values = new ContentValues();
			values.put("city_name", city.getCityName());
			values.put("city_code", city.getCityCode());
			values.put("province_id", city.getProvinceId());
			db.insert("City", null, values);
		}
	}

	/**
	 * 从数据库读取某省下所有的城市信息。
	 */
	public List<City> loadCities(int provinceId) {
		List<City> list = new ArrayList<City>();
		Cursor cursor = db.query("City", null, "province_id = ?",
				new String[] { String.valueOf(provinceId) }, null, null, null);
		if (cursor.moveToFirst()) {
			do {
				City city = new City();
				city.setId(cursor.getInt(cursor.getColumnIndex("id")));
				city.setCityName(cursor.getString(cursor
						.getColumnIndex("city_name")));
				city.setCityCode(cursor.getString(cursor
						.getColumnIndex("city_code")));
				city.setProvinceId(provinceId);
				list.add(city);
			} while (cursor.moveToNext());
		}
		return list;
	}

	/**
	 * 将County实例存储到数据库。
	 */
	public void saveCounty(County county) {
		if (county != null) {
			ContentValues values = new ContentValues();
			values.put("county_name", county.getCountyName());
			values.put("county_code", county.getCountyCode());
			values.put("city_id", county.getCityId());
			db.insert("County", null, values);
		}
	}

	/**
	 * 从数据库读取某城市下所有的县信息。
	 */
	public List<County> loadCounties(int cityId) {
		List<County> list = new ArrayList<County>();
		Cursor cursor = db.query("County", null, "city_id = ?",
				new String[] { String.valueOf(cityId) }, null, null, null);
		if (cursor.moveToFirst()) {
			do {
				County county = new County();
				county.setId(cursor.getInt(cursor.getColumnIndex("id")));
				county.setCountyName(cursor.getString(cursor
						.getColumnIndex("county_name")));
				county.setCountyCode(cursor.getString(cursor
						.getColumnIndex("county_code")));
				county.setCityId(cityId);
				list.add(county);
			} while (cursor.moveToNext());
		}
		return list;
	}

}

weatherDB 我决定还是下一节 仔细的讲解一下 毕竟 郭大婶 封装的很好