android - 如何使用Intent在Kotlin中放置数据类列表

Question

我想使用Intent发送用于新 Activity 的数据类列表(列表)。
在下面的代码(SplashScreenRepository.kt)中，首先我使用改造连接api(此操作已完成)，当响应成功时，我将数据放入DataPeople列表中。
在第二部分中，我需要将此数据列表发送给带有Intent的新 Activity ，以放入回收器 View 。
因此，我希望将所有信息放入intent.putExtra，但是如何？

数据人

data class DataPeople(
    val name : String,
    val height : String,
    val mass : String,
    val hair_color : String,
    val skin_color : String,
    val eye_color : String,
    val birth_year : String,
    val gender : String
) 

SplashScreenRepository.kt

fun getDataInApi(onFinnish : (List<DataPeople>) -> Unit) {
        val retrofitClient = NetworkUtils.getRetrofitInstance()
        val endpoint = retrofitClient.create(Endpoint::class.java)
        val callDataOfPeople = endpoint.dataOfPeople()

        val list = ArrayList<DataPeople>()

        callDataOfPeople.enqueue(object : Callback<SerializeDataPeople?> {
            override fun onResponse(call: Call<SerializeDataPeople?>, response: Response<SerializeDataPeople?>) {
                response.body().let{
                    val note: SerializeDataPeople? = it

                    loop@ for (i in 0..9) {
                        name = note?.results?.get(i)?.name.toString()
                        height = note?.results?.get(i)?.height.toString()
                        mass = note?.results?.get(i)?.mass.toString()
                        hair_color = note?.results?.get(i)?.hair_color.toString()
                        skin_color = note?.results?.get(i)?.skin_color.toString()
                        eye_color = note?.results?.get(i)?.eye_color.toString()
                        birth_year = note?.results?.get(i)?.birth_year.toString()
                        gender = note?.results?.get(i)?.gender.toString()

                        list.add(DataPeople(name, height, mass, hair_color, skin_color, eye_color, birth_year, gender))
                    }
                    dataPeopleList = list
                    onFinnish(dataPeopleList)
                }
            }

            override fun onFailure(call: Call<SerializeDataPeople?>, t: Throwable) {
                Log.e("onFailure error", t?.message)
                onFinnish(emptyList())
            }
        })
    }

SplashScreen.kt

class SplashScreenActivity : AppCompatActivity() {
    private lateinit var splashScreenViewModel: SplashScreenViewModel

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_splash_screen)

        (...)

        splashScreenViewModel.getIsUpdatingLiveDataLoaded()?.observe(this, Observer{ it ->
            when(it){
                SplashScreenViewModel.States.DONE ->{
                    Toast.makeText(this, "Data is ready.", Toast.LENGTH_LONG).show()

                    splashScreenViewModel.getPeopleLiveData()?.observe(this, Observer {
                        val intent = Intent(this, MainActivity::class.java)
                        intent.putExtra("list", it)
                        startActivity(intent)
                    })
                }
                (...)
            }
        })
    }

Answer 1

您可以使用Room创建一个Sqlite表:

数据人

@Entity
data class DataPeople(
    @PrimaryKey val id :Int,
    val name : String,
    val height : String,
    val mass : String,
    val hair_color : String,
    val skin_color : String,
    val eye_color : String,
    val birth_year : String,
    val gender : String
) 

DataPeopleDao.kt

@Dao
interface DataPeopleDao {
    @Query("SELECT * FROM DataPeople")
    fun getAll(): List<DataPeople>

    @Insert
    fun insertAll(dataPeople:List<DataPeople>)
}

AppDatabase.kt

@Database(entities = arrayOf(DataPeople::class), version = 1)
abstract class AppDatabase : RoomDatabase() {
    abstract fun dataPeopleDao(): DataPeopleDao
}

SplashScreenActivty.kt

override fun onCreate(savedInstanceState: Bundle?) {

    super.onCreate(savedInstanceState)
    val db = Room.databaseBuilder(
            applicationContext,
            AppDatabase::class.java, "database-name"
        ).build()
    splashScreenViewModel.getIsUpdatingLiveDataLoaded()?.observe(this, Observer{ it ->
            when(it){
                SplashScreenViewModel.States.DONE ->{

                    splashScreenViewModel.getPeopleLiveData()?.observe(this, Observer {
                        //execute this line on a background thread
                        db.dataPeopleDao().insertAll(it)
                        val intent = Intent(this, MainActivity::class.java)
                        startActivity(intent)
                    })
                }

            }
        })


}

MainActivity.kt

override fun onCreate(savedInstanceState: Bundle?) {

    val db = Room.databaseBuilder(
            applicationContext,
            AppDatabase::class.java, "database-name"
        ).build()
    //execute this line on a background thread
    val peopleData = db.dataPeopleDao().getAll()


}

更好的方法

您可以使用Fragment代替 Activity ，并使用ViewModel在它们之间使用 share data

但:
我建议避免使用:
第二种方法Singleton可能会伤害您。
第三方法文件总是比数据库慢。