在使用Kotlin和Room数据库将数据从URL中检索并按类别存储的解决方案如下所示:
@Entity(tableName = "items")
data class Item(
@PrimaryKey val id: Int,
val name: String,
val category: String
)
@Dao
interface ItemDao {
@Query("SELECT * FROM items")
fun getAllItems(): List-
@Insert(onConflict = OnConflictStrategy.REPLACE)
fun insertAll(items: List
- )
}
@Database(entities = [Item::class], version = 1)
abstract class AppDatabase : RoomDatabase() {
abstract fun itemDao(): ItemDao
}
class MainActivity : AppCompatActivity() {
private lateinit var db: AppDatabase
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
db = Room.databaseBuilder(
applicationContext,
AppDatabase::class.java, "database-name"
).build()
val url = "https://example.com/data.json"
val request = Request.Builder().url(url).build()
val client = OkHttpClient()
client.newCall(request).enqueue(object : Callback {
override fun onResponse(call: Call, response: Response) {
val json = response.body?.string()
val items = parseJson(json) // 解析JSON数据
// 在后台线程中将数据存储到数据库
Thread {
db.itemDao().insertAll(items)
}.start()
}
override fun onFailure(call: Call, e: IOException) {
e.printStackTrace()
}
})
}
private fun parseJson(json: String?): List- {
val items = mutableListOf
- ()
// 解析JSON数据并添加到items列表中
return items
}
}
以上代码假设你已经添加了相关的依赖项,如Room数据库和OkHttp库。请根据你的实际需求进行适当的修改和调整。