[英]Unable to read sql file from assets in flutter
我正在嘗試將預先填充的數據加載到我的flutter應用程序中。 我已經在項目的根目錄中創建了“ assets”文件夾,並將“ mydb.sql”文件放入該文件夾中。
在pubspec.yaml中添加了該文件引用
assets:
- assets/mydb.sql
下面是我訪問數據庫的DBHandler.dart文件的代碼
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);
}
我得到的錯誤是
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)
在代碼的給定行下面
ByteData數據=等待rootBundle.load(join('assets',dbName));
我的代碼中有2個問題。 寫這個可以幫助其他人犯同樣的錯誤。
1. pubspec.yaml中的縮進
我犯了一個重大的愚蠢錯誤。 我只是看着
assets:
- assets/mydb.sql
我的pubspec文件是這樣的
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
我沒有注意到我的“ flutter:”和“ assets:”處於同一水平。 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
注意縮進(“ assets:”之前的2個空格)
2. sql文件不是db,所以在解決第一個問題后出現了這個問題。 我得到了mydb.sql不是數據庫。 因此,我從Sqlite數據庫瀏覽器將數據庫導出為“ .sqlite”文件。 並更新了我的pubspec和DBHandler文件。
感謝@Shababb Karim的評論指出了pubspec.yaml問題。
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