How to change SQLite database path to different folder (in application directory) using SQliteOpenhelper :android project

huangapple
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英文:

How to change SQLite database path to different folder (in application directory) using SQliteOpenhelper :android project

问题

我目前正在进行Android项目的开发，其中涉及一个SQLite数据库。之前我使用Flutter创建了数据库，并使用以下代码获取用于创建数据库的路径。

  1. // 获取适用于Android和iOS的目录路径，用于存储数据库。
  2. Directory directory = await getApplicationDocumentsDirectory();
  3. String path = directory.path + '/ideaDatabase.db';

它指向路径：

  1. /data/data/com.example.myprojet01/app_flutter/ideaDatabase.db

根据我的需求，我不得不为项目添加Android特定的Java代码，并且我需要从Java和Dart部分都访问上述数据库。有谁可以帮助我如何从Java中访问数据库。
我正在使用SQliteOpenHelper类来访问数据库。

SQLiteOpenHelper默认在以下位置创建数据库：

  1. /data/data/com.example.myprojet01/databases/ideaDatabase.db

是否有可能指定SQLiteOpenHelper从/app_flutter/目录而不是/databases/目录打开数据库？

Java数据库助手代码：

  1. public class Database_Helper_widget extends SQLiteOpenHelper {
  3.     public static final String TAG = "Database_Helper_widget";
  4.     public static final int DATABASE_VERSION = 1;
  5.     public static final String DATABASE_NAME = "ideaDatabase.db";
  7.     public Database_Helper_widget(Context context) {
  8.         super(context, DATABASE_NAME, null, DATABASE_VERSION);
  9.     }
  11.     @Override
  12.     public void onCreate(SQLiteDatabase db) {
  13.         String CreateTable = MycreateString;
  14.         db.execSQL(CreateTable);
  15.     }
  16. }

Flutter代码：

  1. Future<Database> initializeDatabase() async {
  2.     // 获取适用于Android和iOS的目录路径，用于存储数据库。
  3.     Directory directory = await getApplicationDocumentsDirectory();
  4.     String path = directory.path + '/ideaDatabase.db';
  5.     debugPrint('数据库路径：$path');
  6.     // 打开/创建位于给定路径的数据库
  7.     var ideaDatabase =
  8.         await openDatabase(path, version: 1, onCreate: _createDb);
  9.     return ideaDatabase;
  10. }
英文:

I am currently working on Android project, it has a SQLite database. i have created the database using flutter previously and used below code to get path for creating database.

  1. // Get the directory path for both Android and iOS to store database.
  2.     Directory directory = await getApplicationDocumentsDirectory();
  3.     String path = directory.path + &#39;/ideaDatabase.db&#39;;

it points to path

  1. /data/data/com.example.myprojet01/app_flutter/ideaDatabase.db

as per my requirement i had to add android specific code(Java) for the project. and i had to add data/access above database from both java and dart part. can anyone help me how to get access the database from Java.
i am using SQliteOpenhelper class for accessing database.

SQLiteopenhelper is creating database by default in

  1. /data/data/com.example.myprojet01/databases/ideaDatabase.db

Is to possible to make specify SQliteopenhelper to open database from /app_flutter/ directory instead of /databases/.?

Code java database helper

  1. public class Database_Helper_widget extends SQLiteOpenHelper {
  3.     public static final String TAG=&quot;Database_Helper_widget&quot;;
  5.     public static final int DATABASE_VERSION = 1;
  6.     public static final String DATABASE_NAME = &quot;ideaDatabase.db&quot;;
  8.     public Database_Helper_widget(Context context) {
  9.         super(context, DATABASE_NAME, null, DATABASE_VERSION);
  10.     }
  12.     @Override
  13.     public void onCreate(SQLiteDatabase db) {
  15.         String CreateTable=MycreateString;
  16.         db.execSQL(CreateTable);
  17.     }

Code Flutter:

  1.  Future&lt;Database&gt; initializeDatabase() async {
  2.     // Get the directory path for both Android and iOS to store database.
  3.     Directory directory = await getApplicationDocumentsDirectory();
  4.     String path = directory.path + &#39;/ideaDatabase.db&#39;;
  5.     debugPrint(&#39;path to database $path&#39;);
  6.     // Open/create the database at a given path
  7.     var ideaDatabase =
  8.         await openDatabase(path, version: 1, onCreate: _createDb);
  9.     return ideaDatabase;
  10.   }

答案1

得分: 1

注意：回答我自己的问题，不是一个完美的解决方案，而是我暂时使用的一个变通方法。如果您有更好的解决方案，请改进这个答案或添加一个新的答案。

与其使用应用程序目录文件夹（Flutter）来存储数据库，我正在使用"getDatabasesPath()"。这样一来，Android特定的代码和Flutter代码都指向Android中的同一个数据库文件夹（关于iOS我不确定）。

这将指向您的数据库位置：

  1. /data/data/com.example.myprojet01/databases/ideaDatabase.db

这与Java中的SQliteOpenHelper类创建的默认数据库位置相同。

  1.   Future<Database> initializeDatabase() async {
  2.     // 获取用于在Android和iOS上存储数据库的目录路径。
  3.     // Directory directory = await getApplicationDocumentsDirectory();
  4.     String databasePath = await getDatabasesPath();
  5.     String path = databasePath + '/ideaDatabase.db';
  6.     // 在给定路径上打开/创建数据库
  7.     var ideaDatabase =
  8.         await openDatabase(path, version: 1, onCreate: _createDb);
  9.     return ideaDatabase;
  10.   }

这种方法适用于希望从Android特定代码和Flutter代码中访问共同数据库的情况。

英文:

Note: answering my own Question, Not a perfect solution but a Workaround i am using temporarily. If you got a better solution please improve this answer or add a new one.

Rather than using Application directory folder (Flutter) to store databases. I am using "getDatabasesPath()" . This way both Android Specific code and Flutter code points to same database folder in Android (Not sure about IOS)

This points to your databases location:

  1. /data/data/com.example.myprojet01/databases/ideaDatabase.db

which is same as default databases location in created by SQliteOpenHelper class in java.

  1.   Future&lt;Database&gt; initializeDatabase() async {
  2.     // Get the directory path for both Android and iOS to store database.
  3.     // Directory directory = await getApplicationDocumentsDirectory();
  4.     String databasePath = await getDatabasesPath();
  5.     String path = databasePath + &#39;/ideaDatabase.db&#39;;
  6.     // Open/create the database at a given path
  7.     var ideaDatabase =
  8.         await openDatabase(path, version: 1, onCreate: _createDb);
  9.     return ideaDatabase;
  10.   }

This approach works if you want to access common database from both Android Specific code and Flutter code.

huangapple
  • 本文由 发表于 2020年9月29日 01:11:55
  • 转载请务必保留本文链接：https://go.coder-hub.com/64106658.html
  • android
  • android-sqlite
  • flutter
  • java
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