[英]Unable to read sql file from assets in flutter
我正在尝试将预先填充的数据加载到我的flutter应用程序中。 我已经在项目的根目录中创建了“ assets”文件夹,并将“ mydb.sql”文件放入该文件夹中。
在pubspec.yaml中添加了该文件引用
assets:
- assets/mydb.sql
下面是我访问数据库的DBHandler.dart文件的代码
static Database _db;
String dbName = "mydb.sql";
Future<Database> get db async {
if (_db != null) return _db;
_db = await initDb();
return _db;
}
initDb() async {
var databasesPath = await getDatabasesPath();
var path = join(databasesPath, dbName);
var exists = await databaseExists(path);
if (!exists) {
// Should happen only the first time you launch your application
print("Creating new copy from asset");
// Make sure the parent directory exists
try {
await io.Directory(dirname(path)).create(recursive: true);
} catch (_) {}
// Copy from asset
ByteData data = await rootBundle.load(join('assets',dbName));
List<int> bytes =
data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);
// Write and flush the bytes written
await io.File(path).writeAsBytes(bytes, flush: true);
} else {
print("Opening existing database");
}
return await openDatabase(path);
}
我得到的错误是
I/flutter (16900): Creating new copy from asset
E/flutter (16900): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: Unable to load asset: assets/mydb.sql
E/flutter (16900): #0 PlatformAssetBundle.load (package:flutter/src/services/asset_bundle.dart:221:7)
E/flutter (16900): <asynchronous suspension>
E/flutter (16900): #1 DBHandler.initDb (package:MyApp/db/DBHandler.dart:36:40)
在代码的给定行下面
ByteData数据=等待rootBundle.load(join('assets',dbName));
我的代码中有2个问题。 写这个可以帮助其他人犯同样的错误。
1. pubspec.yaml中的缩进
我犯了一个重大的愚蠢错误。 我只是看着
assets:
- assets/mydb.sql
我的pubspec文件是这样的
flutter:
# The following line ensures that the Material Icons font is
# included with your application, so that you can use the icons in
# the material Icons class.
uses-material-design: true
# To add assets to your application, add an assets section, like this:
assets:
- assets/mydb.sqlite
我没有注意到我的“ flutter:”和“ assets:”处于同一水平。 所以我改成
flutter:
# The following line ensures that the Material Icons font is
# included with your application, so that you can use the icons in
# the material Icons class.
uses-material-design: true
# To add assets to your application, add an assets section, like this:
assets:
- assets/mydb.sqlite
注意缩进(“ assets:”之前的2个空格)
2. sql文件不是db,所以在解决第一个问题后出现了这个问题。 我得到了mydb.sql不是数据库。 因此,我从Sqlite数据库浏览器将数据库导出为“ .sqlite”文件。 并更新了我的pubspec和DBHandler文件。
感谢@Shababb Karim的评论指出了pubspec.yaml问题。
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