Android中使用Sqlite数据库 （二） 增删改查

定义接口

package com.example.android_db.service;
import java.util.List;
import java.util.Map;
public interface PersonService {
    public boolean addPerson(Object[] params);
                                  
    public boolean deletePerson(Object[] params);
                                  
    public boolean updatePerson(Object[] params);
                                  
    public Map<String,String> viewPerson(String[] selectionArgs);
                                  
    public List<Map<String,String>> listPersonMaps(String[] selectionArgs);
}

实现接口：

package com.example.android_db.dao;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import com.example.android_db.db.DbOpenHelper;
import com.example.android_db.service.PersonService;
public class PersonDao implements PersonService {
    private DbOpenHelper helper = null;
    public PersonDao(Context context) {
        // TODO Auto-generated constructor stub
        helper = new DbOpenHelper(context);
    }
    @Override
    public boolean addPerson(Object[] params) {
        // TODO Auto-generated method stub
        boolean flag = false;
        //实现对数据库的添加删除和修改查询的功能
        SQLiteDatabase database = null;
        try {
            String sql = "insert into person(name,address,sex) values(?,?,?)";
            database = helper.getWritableDatabase();//实现对数据库的写的操作
            database.execSQL(sql, params);
            flag = true;
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }finally{
            if(database!=null){
                database.close();
            }
        }
        return flag;
    }
    @Override
    public boolean deletePerson(Object[] params) {
        // TODO Auto-generated method stub
        boolean flag = false;
        SQLiteDatabase database = null;
        try {
            String sql = "delete from person where id = ? ";
            database = helper.getWritableDatabase();
            database.execSQL(sql, params);
            flag = true;
        } catch (Exception e) {
            // TODO: handle exception
        }finally{
            if(database!=null){
                database.close();
            }
        }
        return flag;
    }
    @Override
    public boolean updatePerson(Object[] params) {
        // TODO Auto-generated method stub
        boolean flag = false;
        SQLiteDatabase database = null;
        try {
            String sql = "update person set name = ? ,address = ?, sex = ? where id = ? ";
            database = helper.getWritableDatabase();
            database.execSQL(sql, params);
            flag = true;
        } catch (Exception e) {
            // TODO: handle exception
        }finally{
            if(database!=null){
                database.close();
            }
        }
        return flag;
    }
    @Override
    public Map<String, String> viewPerson(String[] selectionArgs) {
        Map<String,String> map = new HashMap<String, String>();
        SQLiteDatabase database = null;
        try {
            String sql = "select * from person where id = ? ";
            database = helper.getReadableDatabase();
            Cursor cursor = database.rawQuery(sql, selectionArgs);
            //获得数据库的列的个数
            int colums = cursor.getColumnCount();
            while(cursor.moveToNext()){
                for(int i=0;i<colums;i++){
                    String cols_name = cursor.getColumnName(i);
                    String cols_value = cursor.getString(cursor.getColumnIndex(cols_name));
                    if(cols_value==null){
                        cols_value = "";
                    }
                    map.put(cols_name, cols_value);
                }
            }
        } catch (Exception e) {
            // TODO: handle exception
        }finally{
            if(database!=null){
                database.close();
            }
        }
        return map;
    }
    @Override
    public List<Map<String, String>> listPersonMaps(String[] selectionArgs) {
        // TODO Auto-generated method stub
        List<Map<String,String>> list = new ArrayList<Map<String,String>>();
        String sql = "select * from person ";
        SQLiteDatabase database = null;
        try {
            database = helper.getReadableDatabase();
            Cursor cursor = database.rawQuery(sql, selectionArgs);
            int colums = cursor.getColumnCount();
            while(cursor.moveToNext()){
                Map<String,String> map = new HashMap<String, String>();
                for(int i=0;i<colums;i++){
                    String cols_name = cursor.getColumnName(i);
                    String cols_value = cursor.getString(cursor.getColumnIndex(cols_name));
                    if(cols_value==null){
                        cols_value="";
                    }
                    map.put(cols_name, cols_value);
                }
                list.add(map);
            }
        } catch (Exception e) {
            // TODO: handle exception
        }finally{
            if(database!=null){
                database.close();
            }
        }
        return list;
    }
}

实现SQLiteOpenHelper的子类

package com.example.android_db.db;
import android.content.Context;
import android.database.DatabaseErrorHandler;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
public class DbOpenHelper extends SQLiteOpenHelper {
    private static String name = "mydb.db";// 表示数据库的名称
    private static int version = 2;// 表示数据库的版本号码
    public DbOpenHelper(Context context) {
        super(context, name, null, version);
    }
    // 当数据库创建的时候，是第一次被执行,完成对数据库的表的创建
    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        //支持的数据类型：整型数据，字符串类型，日期类型，二进制的数据类型，
        String sql = "create table person(id integer primary key autoincrement,name varchar(64),address varchar(64))";
        db.execSQL(sql);
    }
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        String sql = "alter table person add sex varchar(8)";
        db.execSQL(sql);
    }
}

测试类：

package com.example.android_db.test;
import java.util.List;
import java.util.Map;
import com.example.android_db.dao.PersonDao;
import com.example.android_db.db.DbOpenHelper;
import com.example.android_db.service.PersonService;
import android.test.AndroidTestCase;
import android.util.Log;
public class MyTest extends AndroidTestCase {
    public MyTest() {
        // TODO Auto-generated constructor stub
    }
       
    public void createDb(){
        DbOpenHelper helper = new DbOpenHelper(getContext());
        helper.getWritableDatabase();
    }
    public void insertDB(){
        PersonService service = new PersonDao(getContext());
        Object[] params = {"李斯","广西","女"};
        boolean flag = service.addPerson(params);
        System.out.println("--->>"+flag);
    }
       
    public void deleteDB(){
        PersonService service = new PersonDao(getContext());
        Object[] params = {1};
        boolean flag = service.deletePerson(params);
        System.out.println("--->>"+flag);
    }
       
    public void updateDB(){
        PersonService service = new PersonDao(getContext());
        Object[] params = {"王五","上海","不祥","3"};
        service.updatePerson(params);
    }
       
    public void viewDB(){
        PersonService service = new PersonDao(getContext());
        String[] selectionArgs = {"3"};
        Map<String, String> map = service.viewPerson(selectionArgs);
        Log.i("Test", "-->>"+map.toString());
    }
       
    public void listDB(){
        PersonService service = new PersonDao(getContext());
           
        List<Map<String,String>> list = service.listPersonMaps(null);
        Log.i("Test", "-->>"+list.toString());
    }
}

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