SQLite增删改查（利用系统API）

     在SQLite增删改查（自己写SQL语句）中介绍了通过自己写SQL语句来实现增删改查。下面是利用系统API来实现。

一、在上一篇中工程中直接增加PersonService2，PersonDao2和MyTest2类。如图

二、PersonService2详细代码

package com.bruce.db_test.service;

import java.util.List;
import java.util.Map;

import android.content.ContentValues;

public interface PersonService2 {
    public boolean insertPerson(ContentValues values);
    public boolean deletePerson(String whereClause,String[] whereArgs);
    public boolean updatePerson(ContentValues values, String whereClause,String[] whereArgs);
    public Map<String, String> findPerson(String selection, String[] selectionArgs);
    public List<Map<String, String>> listPerson(String selection, String[] selectionArgs);
}

三、PersonDao2详细代码

package com.bruce.dao;

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

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

import com.bruce.db_test.db.DbOpenHelper;
import com.bruce.db_test.service.PersonService2;

public class PersonDao2 implements PersonService2 {
    private String TAG = "MyTest";
    private DbOpenHelper helper = null;
    
    public PersonDao2(Context context){
        helper = new DbOpenHelper(context);
        Log.i(TAG, "-->helper assignment");
    }
    
    @Override
    public boolean insertPerson(ContentValues values) {
        boolean flag = false;
        long id = -1;
        SQLiteDatabase database = null;
        try {
            database = helper.getWritableDatabase();
            id = database.insert("person", null, values);
            flag = (id != -1? true:false);
            Log.i(TAG, "-->insert "+flag +",id=" + id);
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            if(database != null){
                database.close();
            }
        }
        return flag;
    }

    @Override
    public boolean deletePerson(String whereClause,String[] whereArgs) {
        boolean flag = false;
        int count = 0;
        SQLiteDatabase database = null;
        try {
            database = helper.getWritableDatabase();
            count = database.delete("person", whereClause, whereArgs);
            flag = (count > 0 ? true:false);
            Log.i(TAG, "-->delete "+flag +",count=" + count);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return flag;
    }

    @Override
    public boolean updatePerson(ContentValues values, String whereClause,String[] whereArgs) {
        boolean flag = false;
        SQLiteDatabase database = null;
        int count = 0;
        try {
            database = helper.getWritableDatabase();
            count = database.update("person", values, whereClause, whereArgs);
            flag = (count != 0 ? true: false);
            Log.i(TAG, "-->updata " + flag);
        } catch (Exception e) {
            e.printStackTrace();
        } finally{
            if(database != null){
                database.close();
            }
        }
        return flag;
    }

    @Override
    public Map<String, String> findPerson(String selection, String[] selectionArgs) {
        Map<String, String> map = new HashMap<String, String>();
        SQLiteDatabase database = null;
        Cursor cursor = null;
        Log.i(TAG, "-->findPerson begin");
        try {
            database = helper.getWritableDatabase();
            cursor = database.query(false, "person", null, selection, selectionArgs, null, null, null, null, null);
            int count = cursor.getColumnCount();
            while (cursor.moveToNext()) {
                for(int i=0;i<count;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) {
            e.printStackTrace();
        }finally{
            if(database != null){
                database.close();
            }
        }
        System.out.println("-->map:"+ map.toString());
        return map;
    }

    @Override
    public List<Map<String, String>> listPerson(String selection, String[] selectionArgs) {
        List<Map<String, String>> list =  new ArrayList<Map<String,String>>();
        SQLiteDatabase database = null;
        Cursor cursor = null;
        try {
            database = helper.getReadableDatabase();
            cursor = database.query(false, "person", null, selection, selectionArgs, null, null, null, null, null);
            int count = cursor.getColumnCount();
            while(cursor.moveToNext()){
                Map<String, String> map = new HashMap<String, String>();
                for(int i=0;i<count;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) {
            e.printStackTrace();
        } finally{
            if(database != null){
                database.close();
            }
        }
        return list;
    }

}

四、MyTest2详细代码

package com.bruce.db_test.test;

import java.util.List;
import java.util.Map;

import com.bruce.dao.PersonDao2;
import com.bruce.db_test.service.PersonService2;

import android.Manifest.permission;
import android.content.ContentValues;
import android.test.AndroidTestCase;
import android.util.Log;

public class MyTest2 extends AndroidTestCase {
    private String TAG = "MyTest";
    
    public void insertTest(){
        PersonService2 service2 = new PersonDao2(getContext());
        ContentValues values = new ContentValues();
        values.put("name", "星爷");
        values.put("address", "香港");
        values.put("sex", "男");
        boolean flag = service2.insertPerson(values);
        Log.i(TAG, "test insert end,flag="+ flag);
    }
    
    public void deletePersonTest() {
        PersonService2 service2 = new PersonDao2(getContext());
        String[] whereArgs = {"5"};
        boolean flag = service2.deletePerson(" id = ? ", whereArgs);
        Log.i(TAG, "test delete end,flag="+ flag);
    }
    
    public void updatePersonTest(){
        PersonService2 service2 = new PersonDao2(getContext());
        ContentValues values = new ContentValues();
        values.put("name", "老毛");
        values.put("address", "北京");
        values.put("sex", "No");
        String[] whereArgs = {"1"};
        //boolean flag = service2.updatePerson(values, " id = ? ", new String[]{"1"});
        boolean flag = service2.updatePerson(values, " id = ? ", whereArgs);
        Log.i(TAG, "-->test " + flag);
    }
    
    public void viewPersonTest(){
        Log.i(TAG, "-->viewPerson begin");
        PersonService2 service2 = new PersonDao2(getContext());
        String selection = " id = ? ";
        String[] selectionArgs = {"1"};
        Map<String, String> map = service2.findPerson(selection, selectionArgs);
        Log.i(TAG, "--->viewPerson" + map.toString());
    }
    
    public void listPersonTest(){
        PersonService2 service2 = new PersonDao2(getContext());
        
        List<Map<String, String>> list = service2.listPerson(null, null);
        Log.i(TAG, "--->list test:" + list.toString());
    }
}

五、以下是测试时的一些输出信息