仅为调试构建添加房间数据库迁移

Question

我创建数据库的函数是这样的：

    operator fun invoke(context: Context) = instance ?: synchronized(LOCK) {
        instance ?: buildDatabase(context).also { instance = it }
    }

并建立数据库：

private fun buildDatabase(context: Context) = Room.databaseBuilder(context, 
AppDatabase::class.java, "Rides.db")
        .addMigrations(MIGRATION_1_2)
        .addMigrations(MIGRATION_2_3)
        .build()

我需要的是MIGRATION_2_3只会在调试模式下发生，像这样（伪）：

 private fun buildDatabase(context: Context) = Room.databaseBuilder(context, 
 AppDatabase::class.java, "Rides.db")
        .addMigrations(MIGRATION_1_2)
    if (BuildConfig.Debug)
    {
        .addMigrations(MIGRATION_2_3)
    }
       
        .build()
}

在不创建两个 buildDatabase 函数的情况下实现此目的的正确语法是什么？

Answer 1

您已经提到了它的伪代码。您可以获得构建器并添加条件，然后 return builder.build().

private fun buildDatabase(context: Context):AppDatabase {
        val builder = Room.databaseBuilder(
            context,
            AppDatabase::class.java, "Rides.db"
        )
            .addMigrations(MIGRATION_1_2)
        if (BuildConfig.DEBUG) {
            builder.addMigrations(MIGRATION_2_3)
        }
        return builder.build()
    }

或

private fun buildDatabase(context: Context): AppDatabase =
        Room.databaseBuilder(
            context,
            AppDatabase::class.java, "Rides.db"
        ).apply {
            addMigrations(MIGRATION_1_2)
            if (BuildConfig.DEBUG) {
                addMigrations(MIGRATION_2_3)
            }
        }.build()

仅为调试构建添加房间数据库迁移

Add room DB migration only for Debug build

android

database-migration

android-room