英文:
Get Context in Android Room Migration
问题
Sure, here is the translated content:
在Android Room迁移中获取上下文：
在我的迁移中，我想获取上下文以从资产中读取一些文件：
@Module@InstallIn(SingletonComponent::class)objectPersistenceModule : Application() {@Provides@Singletonfun provideAppDatabase(@ApplicationContext context: Context,): AppDatabase = Room.databaseBuilder(context, AppDatabase::class.java, "app").addMigrations(MIGRATION_3_4).build()}
val MIGRATION_3_4 = object : Migration(3, 4) {override fun migrate(database: SupportSQLiteDatabase) {//...val txt = context.resources.assets.open("example.txt").bufferedReader().use { it.readText() }}}
Please note that the code remains in Kotlin, and I've translated the comments and string literals.
英文:
Get Context in Android Room Migration:
In my Migration i want to get context to read some files from assets:
@Module@InstallIn(SingletonComponent::class)objectPersistenceModule : Application() {@Provides@Singletonfun provideAppDatabase(@ApplicationContext context: Context,): AppDatabase = Room.databaseBuilder(context, AppDatabase::class.java, "app").addMigrations(MIGRATION_3_4).build()}
val MIGRATION_3_4 = object : Migration(3, 4) {override fun migrate(database: SupportSQLiteDatabase) {//...val txt = context.resources.assets.open("example.txt").bufferedReader().use { it.readText() }}}
答案1
得分: 1
Create a class extending Migration which takes context as parameter in constructor
class Migration3to4(@ApplicationContext val context: Context): Migration(3, 4) {override fun migrate(database: SupportSQLiteDatabase) {// access context hereval txt = context.resources.assets.open("example.txt").bufferedReader().use { it.readText() }}}
Callsite
@Module@InstallIn(SingletonComponent::class)object PersistenceModule {@Provides@Singletonfun provideAppDatabase(@ApplicationContext context: Context,): AppDatabase = Room.databaseBuilder(context, AppDatabase::class.java, "app").addMigrations(Migration3to4(context)).build()}
英文:
Create a class extending Migration which takes context as parameter in constructor
class Migration3to4(@ApplicationContext val context: Context): Migration(3.4) {override fun migrate(database: SupportSQLiteDatabase) {// access context hereval txt = context.resources.assets.open("example.txt").bufferedReader().use { it.readText() }}}
Callsite
@Module@InstallIn(SingletonComponent::class)objectPersistenceModule : Application() {@Provides@Singletonfun provideAppDatabase(@ApplicationContext context: Context,): AppDatabase = Room.databaseBuilder(context, AppDatabase::class.java, "app").addMigrations(Migration3to4(context)).build()}
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