第一行代码酷欧天气开发(一)

第一阶段我们要做的就是创建数据库和表,这样服务器获取到的数据才能保存到本地,province,city,county这三张表,

package com.coolweather.app.db;

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

public class CoolWeatherOpenHelper extends SQLiteOpenHelper{
    String TAG = "CoolWeatherOpenHelper";
    /**
     * Province建表语句
     */
    public static final String CREATE_PROVINCE = "create table Province("
            + "id integer primary key autoincrement,"//自增长主键
            + "province_name text,"//省名
            + "province_code text)";//省级代号

    /**
     * City建表语句
     */
    public static final String CREATE_CITY = "create table City("
            + "id integer primary key autoincrement,"//自主增长键
            + "city_name text,"//城市名
            + "city_code text,"//市级代号
            + "province_id integer)";//City表关联Province表的外键
    /**
     * County 表建表语句
     */
    public static final String CREATE_COUNTY = "create table County("
            + "id integer primary key autoincrement,"//自主增长键
            + "county_name text,"//县名
            + "county_code text,"//县级代号
            + "city_id integer)";//County表链City表的外键

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

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(CREATE_PROVINCE);
        Log.i(TAG, "province created");
        db.execSQL(CREATE_CITY);
        Log.i(TAG, "city created");
        db.execSQL(CREATE_COUNTY);
        Log.i(TAG, "county created");

    }

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

    }

}

上面的代码很简单,也很容易了解,三条建表语句,然后再oncreate方法里面执行。
然后,很正常的我们就应该想到应该建立几个实体类了,方便后续的开发工作,因此,在model包下建立Province类

package com.coolweather.app.model;

/**
 * province的实体类,方便对province的操作
 * @author aiyuan
 * @time 2016.9.7
 */
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;
    }

}

接着在model包下建立City类

package com.coolweather.app.model;

/**
 * City的实体类,方便对City的操作
 * @author aiyuan
 * @time 2016.9.7
 *
 */
public class City {
    private int id;
    private String cityName;
    private String cityCode;
    private int provincdId;
    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 provincdId;
    }
    public void setProvinceId(int provinceId){
        this.provincdId = provinceId;
    }

}

然后在model包下建立County类

package com.coolweather.app.model;

/**
 * County的实体类,方便对County的操作
 * @author aiyuan
 * @time 2016.9.7
 *
 */
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;
    }


}

是不是感觉很简单,没错,这三个实体类就是只有些字段和一些get,set方法,用于获取和设置相应的字段。
接下来,我们还需要创建一个Cool WeatherDB类,将我们一些常用的数据库操作封装起来,以便后续使用

package com.coolweather.app.db;

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

import com.coolweather.app.model.City;
import com.coolweather.app.model.County;
import com.coolweather.app.model.Province;

import android.Manifest.permission;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.util.Log;

/**
 * 把一些常用的数据库操作封装起来,方便日后使用
 * @author aiyuan
 * @time 2016.9.7
 *
 */
public class CoolWeatherDB {
    String TAG = "CoolWeatherDB";
    /**
     * 数据库名
     */

    public static final String DB_NAME = "cool_weather";
    /**
     * 数据库版本
     */

    public static final int VERSION = 1;
    private static CoolWeatherDB coolWeatherDB;
    private SQLiteDatabase db;

    /**
     * 将构造方法私有化
     * @param context
     */
    private CoolWeatherDB(Context context) {
        CoolWeatherOpenHelper dbHelper = new CoolWeatherOpenHelper(context, DB_NAME, null, VERSION);
        Log.i(TAG, "dbHelper create success");
        db = dbHelper.getWritableDatabase();
        Log.i(TAG, "db create success");
    }

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

    /**
     * 将province实例存储到数据库
     * @param province
     */
    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);
        }
    }

    /**
     * 从数据库读取全国的所有省份信息
     * @return List
     */
    public List loadProvince(){
        List list = new ArrayList();
        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());
        }
        if(cursor != null)
            cursor.close();
        return list;
    }

    /**
     * 将City实例存储到数据库
     * @param city
     */
    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
     * @param provinceId
     * @return List
     */
    public List loadCities(int provinceId){
        List list = new ArrayList();
        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());
        }
        if(cursor != null)
            cursor.close();
        return list;
    }

    /**
     * 将County实例 存入数据库
     * @param county
     */
    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
     * @param cityId
     * @return List
     */
    public List loadCounties(int cityId){
        List list = new ArrayList();
        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")));
                Log.d(TAG,cursor.getString(cursor.getColumnIndex("county_name"))+"hell");
                Log.d(TAG,cursor.getString(cursor.getColumnIndex("county_code"))+"hell");
                county.setCityId(cityId);
                list.add(county);
            }while(cursor.moveToNext());

        }
        if(cursor != null)
            cursor.close();
        return list;
    }

}

可以看到,这个CoolWeatherDB类并没有继承别的什么类,通过Ctrl+o我们可以看到这个类里面有这么些东西
第一行代码酷欧天气开发(一)_第1张图片
其中,getInstance方法用于获取Cool WeatherDB的实例,这样就保证在全局范围内只有一个Cool WeatherDB的实例,接下来,有六个方法,
分别用于存储省份数据,读取省份数据,存取城市数据,读取城市数据,存储县数据,读取县数据,下面我以省份的存储和读取为例,讲解一下,城市,县的存储和读取和省的差不多
saveprovince()方法
第一行代码酷欧天气开发(一)_第2张图片
loadProvince()方法
第一行代码酷欧天气开发(一)_第3张图片
第一阶段完!!请看下一阶段!
第一行代码酷欧天气开发(二)

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