要实现Android分页库和Room关系的解决方案,可以按照以下步骤进行:
implementation "androidx.paging:paging-runtime:3.0.0"
implementation "androidx.room:room-runtime:2.3.0"
kapt "androidx.room:room-compiler:2.3.0"
@Entity(tableName = "users")
data class User(
@PrimaryKey val id: Int,
val name: String,
val age: Int
)
@Dao
interface UserDao {
@Query("SELECT * FROM users")
fun getUsers(): PagingSource
@Insert(onConflict = OnConflictStrategy.REPLACE)
suspend fun insertUsers(users: List)
}
@Database(entities = [User::class], version = 1)
abstract class AppDatabase : RoomDatabase() {
abstract fun userDao(): UserDao
}
class UserPagingSource(
private val userDao: UserDao
) : PagingSource() {
override suspend fun load(params: LoadParams): LoadResult {
try {
val nextPage = params.key ?: 1
val users = userDao.getUsers()
LoadResult.Page(
data = users,
prevKey = null,
nextKey = nextPage + 1
)
} catch (e: Exception) {
LoadResult.Error(e)
}
}
}
class UserViewModel(
private val userDao: UserDao
) : ViewModel() {
fun getUsers(): Flow> {
return Pager(PagingConfig(pageSize = 20)) {
UserPagingSource(userDao)
}.flow
}
}
class MainActivity : AppCompatActivity() {
private val viewModel: UserViewModel by viewModels()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val adapter = UserAdapter()
val recyclerView = findViewById(R.id.recyclerView)
recyclerView.adapter = adapter
lifecycleScope.launch {
viewModel.getUsers().collectLatest { pagingData ->
adapter.submitData(pagingData)
}
}
}
}
以上就是Android分页库和Room关系的解决方案,通过这种方式可以使用分页库和Room来实现数据库查询和分页加载的功能。