在Android文件夹结构中,现有的SQLite数据库应该放在哪里?是drawable文件夹还是layout文件夹?
我没有找到任何解决方案。
将不胜感激任何帮助。
我没有找到任何解决方案。
将不胜感激任何帮助。
你应该将它放在assets
文件夹中。这样,你可以确保它会附加到你的apk中。
以下是如何将数据库文件从assets文件夹复制到你的工作目录:
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();
}
现在从目录中读取数据库:
public void openDataBase() throws SQLException{
//Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
drawable
或layout
不适用于数据库。如果您想要在应用中分发预设数据库,则放置在哪里并不重要(除了当您尝试将其放置在drawable
或layout
中时,您将无法构建您的应用程序)。最合理的地方是assets
文件夹。还有一个非常好的助手可以帮助您设置这样的数据库以供应用程序使用:https://github.com/jgilfelt/android-sqlite-asset-helper。路径:data -> data -> com.yourcompany.yourappid -> 数据库 或者您可以使用Astro文件管理器应用程序在您的设备上找到数据库并浏览设备的文件夹结构。
以下代码演示如何定位您设备上的SQL数据库文件:
var dbName = 'dbData';
var dbPath;
var dbFile;
if ( Ti.Platform.osname == 'android' ) {
dbPath = 'file:///data/data/' + Ti.App.getID() + '/databases/';
dbFile = Ti.Filesystem.getFile( dbPath + dbName );
}
else {
dbPath = Ti.Filesystem.applicationSupportDirectory + '/database/';
dbFile = Ti.Filesystem.getFile( dbPath + dbName + '.sql' );
}
你应该将外部数据库文件放在 assets 文件夹中:
然后为其创建一个类。
package com.appgiudeextra.Database;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
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;
import com.appguideextra.Items.MasterItem;
public class DBConnect extends SQLiteOpenHelper {
public int GetCursor;
// ****************** Declare all the global variable
// ****************************//
private Context myContext;
public String DB_PATH = "data/data/com.appguideextra/databases/"; // path
// of
// your
// datbase
public static String DB_NAME = "AppGuide.sqlite";// your database name
static String ASSETS_DB_FOLDER = "db";
private SQLiteDatabase db;
public DBConnect(Context context, String db_name) {
super(context, db_name, null, 2);
if (db != null && db.isOpen())
close();
this.myContext = context;
DB_NAME = db_name;
try {
createDataBase();
openDataBase();
} catch (IOException e) {
// System.out.println("Exception in creation of database : "+
// e.getMessage());
e.printStackTrace();
}
}
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {
// System.out.println("Database Exist");
} else {
this.getReadableDatabase();
try {
copyDatabase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
private void copyDatabase() throws IOException {
InputStream input = myContext.getAssets().open(DB_NAME);
String outputFileName = DB_PATH + DB_NAME;
OutputStream output = new FileOutputStream(outputFileName);
byte[] buffer = new byte[1024];
int length;
while ((length = input.read(buffer)) > 0) {
output.write(buffer, 0, length);
}
// Close the streams
output.flush();
output.close();
input.close();
// System.out.println(DB_NAME + "Database Copied !");
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
public void openDataBase() throws SQLException {
// Open the database
String myPath = DB_PATH + DB_NAME;
db = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
}
public boolean isOpen() {
if (db != null)
return db.isOpen();
return false;
}
@Override
public synchronized void close() {
if (db != null)
db.close();
super.close();
}
private boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH + DB_NAME;
// System.out.println("My Pathe is:- " + myPath);
// System.out.println("Open");
checkDB = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
// System.out.println("checkDB value:" + checkDB);
// System.out.println("My Pathe is:- " + myPath);
} catch (Exception e) {
// database does't exist yet.
}
if (checkDB != null) {
// System.out.println("Closed");
checkDB.close();
// System.out.println("My db is:- " + checkDB.isOpen());
}
return checkDB != null ? true : false;
}
public Cursor execCursorQuery(String sql) {
Cursor cursor = null;
try {
cursor = db.rawQuery(sql, null);
GetCursor = cursor.getCount();
Log.i("Inside execCursorQuery try", sql);
} catch (Exception e) {
Log.i("Inside execCursorQuery exception", e.getMessage());
}
return cursor;
}
public void execNonQuery(String sql) {
try {
db.execSQL(sql);
// Log.d("SQL", sql);
} catch (Exception e) {
// Log.e("Err", e.getMessage());
} finally {
// closeDb();
}
}}