بهترین روش ذخیره سازی

import java.io.InputStream;
import java.io.BufferedReader;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
InputStream is = this.getResources().openRawResource(R.raw.textfile);
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String str = null;
try {
while ((str = br.readLine()) != null) {
Toast.makeText(getBaseContext(),
str, Toast.LENGTH_SHORT).show();
}
is.close();
br.close();
} catch (IOException e) {
e.printStackTrace();
}
textBox = (EditText) findViewById(R.id.txtText1);
Button saveBtn = (Button) findViewById(R.id.btnSave);
Button loadBtn = (Button) findViewById(R.id.btnLoad);
saveBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
}
});
loadBtn.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
}
});
}

package com.PRG.Databases;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DBAdapter {
public static final String KEY_ROWID = “_id”;
public static final String KEY_NAME = “name”;
public static final String KEY_EMAIL = “email”;
private static final String TAG = “DBAdapter”;
private static final String DATABASE_NAME = “MyDB”;
private static final String DATABASE_TABLE = “contacts”;
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_CREATE =
“create table contacts (_id integer primary key autoincrement, “
+ “name text not null, email text not null);”;
private final Context context;
private DatabaseHelper DBHelper;
private SQLiteDatabase db;
public DBAdapter(Context ctx)
{
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db)
{
try {
db.execSQL(DATABASE_CREATE);
} catch (SQLException e) {
e.printStackTrace();
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
Log.w(TAG, “Upgrading database from version “ + oldVersion + “ to “
+ newVersion + “, which will destroy all old data”);
db.execSQL(“DROP TABLE IF EXISTS contacts”);
onCreate(db);
}
}
//---opens the database---
public DBAdapter open() throws SQLException
{
db = DBHelper.getWritableDatabase();
return this;
}
//---closes the database---
public void close()
{
DBHelper.close();
}
//---insert a contact into the database---
public long insertContact(String name, String email)
{
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_NAME, name);
initialValues.put(KEY_EMAIL, email);
return db.insert(DATABASE_TABLE, null, initialValues);
}
//---deletes a particular contact---
public boolean deleteContact(long rowId)
{
return db.delete(DATABASE_TABLE, KEY_ROWID + “=” + rowId, null) > 0;
}
//---retrieves all the contacts---
public Cursor getAllContacts()
{
return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_NAME,
KEY_EMAIL}, null, null, null, null, null);
}
//---retrieves a particular contact---
public Cursor getContact(long rowId) throws SQLException
{
Cursor mCursor =
db.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
KEY_NAME, KEY_EMAIL}, KEY_ROWID + “=” + rowId, null,
null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
//---updates a contact---
public boolean updateContact(long rowId, String name, String email)
{
ContentValues args = new ContentValues();
args.put(KEY_NAME, name);
args.put(KEY_EMAIL, email);
return db.update(DATABASE_TABLE, args, KEY_ROWID + “=” + rowId, null) > 0;
}
}

public static final String KEY_ROWID = “_id”;
public static final String KEY_NAME = “name”;
public static final String KEY_EMAIL = “email”;
private static final String TAG = “DBAdapter”;
private static final String DATABASE_NAME = “MyDB”;
private static final String DATABASE_TABLE = “contacts”;
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_CREATE =
“create table contacts (_id integer primary key autoincrement, “
+ “name text not null, email text not null);”;

public class DBAdapter {
public static final String KEY_ROWID = “_id”;
public static final String KEY_NAME = “name”;
public static final String KEY_EMAIL = “email”;
private static final String TAG = “DBAdapter”;
private static final String DATABASE_NAME = “MyDB”;
private static final String DATABASE_TABLE = “contacts”;
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_CREATE =
“create table contacts (_id integer primary key autoincrement, “
+ “name text not null, email text not null);”;
private final Context context;
private DatabaseHelper DBHelper;
private SQLiteDatabase db;
public DBAdapter(Context ctx)
{
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}
private static class DatabaseHelper extends SQLiteOpenHelper
{
DatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db)
{
try {
db.execSQL(DATABASE_CREATE);
} catch (SQLException e) {
e.printStackTrace();
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
Log.w(TAG, “Upgrading database from version “ + oldVersion + “ to “
+ newVersion + “, which will destroy all old data”);
db.execSQL(“DROP TABLE IF EXISTS contacts”);
onCreate(db);
}
}

public class DBAdapter {
//...
//...
//---opens the database---
public DBAdapter open() throws SQLException
{
db = DBHelper.getWritableDatabase();
return this;
}
//---closes the database---
public void close()
{
}
//---insert a contact into the database---
public long insertContact(String name, String email)
{
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_NAME, name);
initialValues.put(KEY_EMAIL, email);
return db.insert(DATABASE_TABLE, null, initialValues);
}
//---deletes a particular contact---
public boolean deleteContact(long rowId)
{
return db.delete(DATABASE_TABLE, KEY_ROWID + “=” + rowId, null) > 0;
}
//---retrieves all the contacts---
public Cursor getAllContacts()
{
return db.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_NAME,
KEY_EMAIL}, null, null, null, null, null);
}
//---retrieves a particular contact---
public Cursor getContact(long rowId) throws SQLException
{
Cursor mCursor =
db.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
KEY_NAME, KEY_EMAIL}, KEY_ROWID + “=” + rowId, null,
null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
//---updates a contact---
public boolean updateContact(long rowId, String name, String email)
{
ContentValues args = new ContentValues();
args.put(KEY_NAME, name);
args.put(KEY_EMAIL, email);
return db.update(DATABASE_TABLE, args, KEY_ROWID + “=” + rowId, null) > 0;
}
}

package com.PRG.Databases;
import android.app.Activity;
import android.os.Bundle;
public class MainActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
DBAdapter db = new DBAdapter(this);
//---add a contact---
db.open();
long id = db.insertContact(“Wei-Meng Lee”, “این آدرس ایمیل توسط spambots حفاظت می شود. برای دیدن شما نیاز به جاوا اسکریپت دارید”);
id = db.insertContact(“Mary Jackson”, “این آدرس ایمیل توسط spambots حفاظت می شود. برای دیدن شما نیاز به جاوا اسکریپت دارید”);
db.close();
}
}

DBAdapter db = new DBAdapter(this);

package com.PRG.Databases;
import android.app.Activity;
import android.os.Bundle;
import android.widget.Toast;
import android.database.Cursor;
public class MainActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
DBAdapter db = new DBAdapter(this);
/*
//---add a contact---
db.open();
long id = db.insertContact(“Wei-Meng Lee”, “این آدرس ایمیل توسط spambots حفاظت می شود. برای دیدن شما نیاز به جاوا اسکریپت دارید”);
id = db.insertContact(“Mary Jackson”, “این آدرس ایمیل توسط spambots حفاظت می شود. برای دیدن شما نیاز به جاوا اسکریپت دارید”);
db.close();
*/
//---get all contacts---
db.open();
Cursor c = db.getAllContacts();
if (c.moveToFirst())
{
do {
DisplayContact(c);
} while (c.moveToNext());
}
db.close();
}
public void DisplayContact(Cursor c)
{
Toast.makeText(this,
“id: “ + c.getString(0) + “\n” +
“Name: “ + c.getString(1) + “\n” +
“Email: “ + c.getString(2),
Toast.LENGTH_LONG).show();
}
}

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
DBAdapter db = new DBAdapter(this);
/*
//---add a contact---
//...
*/
/*
//---get all contacts---
//...
*/
//---get a contact---
db.open();
Cursor c = db.getContact(2);
if (c.moveToFirst())
DisplayContact(c);
else
Toast.makeText(this, “No contact found”, Toast.LENGTH_LONG).show();
db.close();
}

Cursor c = db.getContact(2);

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
DBAdapter db = new DBAdapter(this);
/*
//---add a contact---
//...
*/
/*
//---get all contacts---
//...
*/
/*
//...
*/
//---update contact---
db.open();
if (db.updateContact(1, “Wei-Meng Lee”, “این آدرس ایمیل توسط spambots حفاظت می شود. برای دیدن شما نیاز به جاوا اسکریپت دارید”))
Toast.makeText(this, “Update successful.”, Toast.LENGTH_LONG).show();
else
Toast.makeText(this, “Update failed.”, Toast.LENGTH_LONG).show();
db.close();
}

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
DBAdapter db = new DBAdapter(this);
/*
//---add a contact---
//...
*/
/*
//---get all contacts---
//...
*/
/*
//---get a contact---
//...
*/
/*
//---update contact---
//...
*/
//---delete a contact---
db.open();
if (db.deleteContact(1))
Toast.makeText(this, “Delete successful.”, Toast.LENGTH_LONG).show();
else
Toast.makeText(this, “Delete failed.”, Toast.LENGTH_LONG).show();
db.close();
}

public class DBAdapter {
public static final String KEY_ROWID = “_id”;
public static final String KEY_NAME = “name”;
public static final String KEY_EMAIL = “email”;
private static final String TAG = “DBAdapter”;
private static final String DATABASE_NAME = “MyDB”;
private static final String DATABASE_TABLE = “contacts”;
private static final int DATABASE_VERSION = 2;

DBAdapter(24096): Upgrading database from version 1 to 2, which will destroy all
old data

@Overrid
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
try {
String destPath = “/data/data/” + getPackageName() +
“/databases/MyDB”;
File f = new File(destPath);
if (!f.exists()) {
CopyDB( getBaseContext().getAssets().open(“mydb”),
new FileOutputStream(destPath));
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
DBAdapter db = new DBAdapter(this);
//---get all contacts---
db.open();
Cursor c = db.getAllContacts();
if (c.moveToFirst())
{
do {
DisplayContact(c);
} while (c.moveToNext());
}
db.close();
}
public void CopyDB(InputStream inputStream,
OutputStream outputStream)
throws IOException {
//---copy 1K bytes at a time---
byte[] buffer = new byte[1024];
int length;
while ((length = inputStream.read(buffer)) > 0) {
outputStream.write(buffer, 0, length);
}
inputStream.close();
outputStream.close();
}

public void CopyDB(InputStream inputStream,
OutputStream outputStream)
throws IOException {
//---copy 1K bytes at a time---
byte[] buffer = new byte[1024];
int length;
while ((length = inputStream.read(buffer)) > 0) {
outputStream.write(buffer, 0, length);
}
inputStream.close();
outputStream.close();
}

try {
String destPath = “/data/data/” + getPackageName() +
“/databases/MyDB”;
File f = new File(destPath);
if (!f.exists()) {
CopyDB( getBaseContext().getAssets().open(“mydb”),
new FileOutputStream(destPath));
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}