在android项目里使用自带的SQLite数据库

好久没写博客了，因为项目需要，最近在研究android，使用android默认的访问sqlite的方法，访问的是：data/data/你的项目package/database/数据库名称下的数据库，假如要在项目中打包db文件，该怎么弄呢？

在网上看到一个老外的方法：

publicclass DataBaseHelper extends SQLiteOpenHelper{

//The
Android's default system path of your application database.
private static String DB_PATH =
"/data/data/你的项目package/databases/";

private static String DB_NAME = "数据库名称";

private SQLiteDatabase
myDataBase;

private final Context myContext;


public DataBaseHelper(Context context)
{

super(context, DB_NAME, null, 1);
this.myContext =
context;
}


public void createDataBase() throws IOException{

boolean dbExist =
checkDataBase();

if(dbExist){
//do
nothing - database already exist
}else{

//By
calling this method and empty database will be created into the default system
path
//of your application so we are gonna be able to
overwrite that database with our database.
this.getReadableDatabase();

try {

copyDataBase();

} catch (IOException e) {

throw new Error("Error copying
database");

}
}

}


private boolean
checkDataBase(){

SQLiteDatabase checkDB = null;

try{
String myPath = DB_PATH +
DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READONLY);

}catch(SQLiteException e){

//database
does't exist yet.

}

if(checkDB != null){

checkDB.close();

}

return checkDB != null ? true : false;
}


private void copyDataBase() throws IOException{

//Open your
local db as the input stream
InputStream myInput =
myContext.getAssets().open(DB_NAME);

// Path to
the just created empty db
String outFileName = DB_PATH +
DB_NAME;

//Open the empty db as the output stream
OutputStream myOutput = new
FileOutputStream(outFileName);

//transfer
bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length =
myInput.read(buffer))>0){
myOutput.write(buffer, 0,
length);
}

//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();

}

public void openDataBase() throws SQLException{

//Open the
database
String myPath =
DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READONLY);

}

@Override
public synchronized void close() {

if(myDataBase != null)
myDataBase.close();

super.close();

}

@Override
public void onCreate(SQLiteDatabase db)
{

}

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

}

// Add your
public helper methods to access and get content from the
database.
// You could return cursors by doing "return
myDataBase.query(....)" so it'd be easy
// to you
to create adapters for your views.

}

下面就可以使用 该 类实现数据库的操作了

DataBaseHelper
myDbHelper = new DataBaseHelper(null);
myDbHelper = new DataBaseHelper(this);

try
{

myDbHelper.createDataBase();

} catch (IOException ioe) {

throw new Error("Unable to create
database");

}

try
{

myDbHelper.openDataBase();

}catch(SQLException sqle){

throw sqle;

}

实例化该类之后 就能在 data/data/your_project_package/database/
文件夹下面看到你的sqlite数据库文件了。