Android五大存储之SQLite

前序:

Android五大存储:内部存储外部存储、网络存储、SharedPreferencesSQLite

这次不废话了,讲到的知识除了SQLite  还涉及到单元测试框架,请看下图:

《Android五大存储之SQLite》

英文看不懂没关系,看到绿色长条说明测试运行成功!!!

正文:

直接看代码:

/**

* Created by xuchen on 2016/9/1.

*/

public class MyOpenHelper extends SQLiteOpenHelper {

public MyOpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {

super(context, name, factory, version);

}

//数据库创建的时候调用此方法

@Override

public void onCreate(SQLiteDatabase db) {

db.execSQL(“create table person(_id integer primary key autoincrement,name char(10),salary) char(20),phone integer(20))”);

Log.e(“onCreate: “, “数据库创建了”);

}

//数据库升级时调用此方

@Override

public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

Log.e(“onUpgrade: “, “数据库升级了”);

}

SQLiteOpenHelper  顾名思义SQLite打开帮助类,最重要的便是这三个方法了onCreate();   onUpgrade(); MyOpenHelper();

测试:

public class TextCase extends AndroidTestCase {

private MyOpenHelper myOpenHelper;

private SQLiteDatabase db;

public void text(){

//getContext():获取一个虚拟的上下文

MyOpenHelper myOpenHelper = new MyOpenHelper(getContext(), “peopel.db”, null, 1);

//如果数据库不存在,先创建数据库,再获取可读可写的数据库对象,如果数据库存在,就直接打开

SQLiteDatabase db = myOpenHelper.getWritableDatabase();

}

@Override

protected void setUp() throws Exception {

super.setUp();

myOpenHelper = new MyOpenHelper(getContext(), “people.db”, null, 1);

db = myOpenHelper.getWritableDatabase();

}

@Override

protected void tearDown() throws Exception {

super.tearDown();

db.close();

}

public void insert(){

db.execSQL(“insert into person (name,salary,phone)values(?,?,?)”,new Object[]{“小汪”,”20000″,110});

db.execSQL(“insert into person (name,salary,phone)values(?,?,?)”,new Object[]{“小华”,”25000″,120});

db.execSQL(“insert into person (name,salary,phone)values(?,?,?)”,new Object[]{“小哥”,”30000″,119});

}

public void delete(){

db.execSQL(“delete from person where name =?”,new Object[]{“小汪”});

}

public void update(){

db.execSQL(“update person set phone=? where name=?”,new Object[]{10086,”小华”});

}

public void select(){

Cursor cursor = db.rawQuery(“select name,salary from person”,null);

while (cursor.moveToNext()){

//通过列索引获取列的值

String name = cursor.getString(cursor.getColumnIndex(“name”));

String salary = cursor.getString(cursor.getColumnIndex(“salary”));

Log.e(“select: “,name+”;”+salary);

}

}

/**

* SQLite API;

*/

public void insertAPI(){

//把要插入的数据全部封装至ContentValues对象

ContentValues values = new ContentValues();

values.put(“name”,”德玛西亚”);

values.put(“salary”,”30000″);

values.put(“phone”,911);

db.insert(“person”,null,values);

}

public void deleteAPI(){

int i = db.delete(“person”, “name = ? and _id=?”, new String[]{“德玛西亚”, “3”});

Log.e(“i: “, String.valueOf(i));

}

public void updateAPI(){

ContentValues values = new ContentValues();

values.put(“salary”,50000);

int i = db.update(“person”, values, “name=?”, new String[]{“小哥”});

Log.e(“i: “, String.valueOf(i));

}

public void selectAPI(){

Cursor cursor = db.query(“person”, null, null, null, null, null, null, null);

while (cursor.moveToNext()){

String name = cursor.getString(cursor.getColumnIndex(“name”));

String salary = cursor.getString(cursor.getColumnIndex(“salary”));

String phone = cursor.getString(cursor.getColumnIndex(“phone”));

Log.e(“selectAPI: “,name+”;”+salary+”;”+phone );

}

public void transaction(){

try {

//开启事务

db.beginTransaction();

ContentValues values = new ContentValues();

values.put(“phone”,10010);

db.update(“person”,values,”name=?”,new String[]{“小哥”});

values.clear();

values.put(“salary”,60000);

db.update(“person”,values,”name=?”,new String[]{“小哥”});

//设置事务执行成功

db.setTransactionSuccessful();

}

finally {

//关闭事务,同时提交,如果已经设置事务执行成功,那么sql语句就生效了,反之,sql语句回滚

db.endTransaction();

}

分享:

如果对于如何用Android开发游戏感兴趣的同学可以看这篇文章,链接如下:

五子棋:http://www.jianshu.com/writer#/notebooks/4761187/notes/5418026

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    原文作者:Trap_余生
    原文地址: https://www.jianshu.com/p/d6d12cb443a7
    本文转自网络文章,转载此文章仅为分享知识,如有侵权,请联系博主进行删除。
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