我正在将Kotlin与数据绑定和MVVM体系结构一起使用。我很难让我的适配器使用listAdapter在我的布局上填充数据。由于要使用的库，我必须使用listAdapter（不幸的是没有recyclerView）。这是我的代码：
MainActivityViewModel.kt
class MainActivityViewModel : ViewModel() {
private val movieService: MovieService = RetrofitBuilder.createService()
fun getMovieData(): ArrayList<MovieDataModel> {
val call = movieService.getCurrentlyPlayingMovies(API_KEY)
val movieList = ArrayList<MovieDataModel>(10)
call.enqueue(object : Callback<MovieDataResponse> {
override fun onResponse(call: Call<MovieDataResponse>, response: Response<MovieDataResponse>) {
for (i in 0 until 10) {
movieList.add(response.body()?.results?.get(i)!!)
}
}
override fun onFailure(call: Call<MovieDataResponse>, t: Throwable) {
}
})
return movieList
}
}
MainActivity.kt
class MainActivity : AppCompatActivity() {
lateinit var binding : ActivityMainBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
val mainActivityViewModel = ViewModelProviders.of(this).get(MainActivityViewModel::class.java)
binding.viewModel = mainActivityViewModel
val movieAdapter = MovieAdapter(binding.viewModel!!.getMovieData(), this)
binding.wheelview.adapter = movieAdapter
}
}
MovieApiModels.kt
class MovieDataResponse(val results: List<MovieDataModel>)
class MovieDataModel(val title: String, val overview: String, val release_date: String, val vote_count: String)
activity_main.xml
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<data>
<variable
name="viewModel"
type="com.lucasbrandt.movieselector.MainActivityViewModel"/>
</data>
<android.support.constraint.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.lukedeighton.wheelview.WheelView
android:id="@+id/wheelview"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:wheelColor="@color/colorPrimary"
app:rotatableWheelDrawable="false"
app:selectionAngle="90.0"
app:wheelOffsetY="60dp"
app:repeatItems="true"
app:wheelRadius="200dp"
app:wheelItemCount="10"
app:wheelPadding="13dp"
app:wheelItemRadius="43dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
</android.support.constraint.ConstraintLayout>
</layout>
JSON示例
{
"results": [
{
"popularity": 439.564,
"vote_count": 4901,
"video": false,
"poster_path": "/udDclJoHjfjb8Ekgsd4FDteOkCU.jpg",
"id": 475557,
"adult": false,
"backdrop_path": "/n6bUvigpRFqSwmPp1m2YADdbRBc.jpg",
"original_language": "en",
"original_title": "Joker",
"genre_ids": [
80,
18,
53
],
"title": "Joker",
"vote_average": 8.5,
"overview": "During the 1980s, a failed stand-up comedian is driven insane and turns to a life of crime and chaos in Gotham City while becoming an infamous psychopathic crime figure.",
"release_date": "2019-10-04"
},
{
"popularity": 326.936,
"vote_count": 349,
"video": false,
"poster_path": "/vqzNJRH4YyquRiWxCCOH0aXggHI.jpg",
"id": 290859,
"adult": false,
"backdrop_path": "/rtf4vjjLZLalpOzDUi0Qd2GTUqq.jpg",
"original_language": "en",
"original_title": "Terminator: Dark Fate",
"genre_ids": [
28,
878
],
"title": "Terminator: Dark Fate",
"vote_average": 6.6,
"overview": "More than two decades have passed since Sarah Connor prevented Judgment Day, changed the future, and re-wrote the fate of the human race. Dani Ramos is living a simple life in Mexico City with her brother and father when a highly advanced and deadly new Terminator – a Rev-9 – travels back through time to hunt and kill her. Dani's survival depends on her joining forces with two warriors: Grace, an enhanced super-soldier from the future, and a battle-hardened Sarah Connor. As the Rev-9 ruthlessly destroys everything and everyone in its path on the hunt for Dani, the three are led to a T-800 from Sarah’s past that may be their last best hope.",
"release_date": "2019-11-01"
},
{
"popularity": 186.869,
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"video": false,
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"adult": false,
"backdrop_path": "/skvI4rYFrKXS73BJxWGH54Omlvv.jpg",
"original_language": "en",
"original_title": "Maleficent: Mistress of Evil",
"genre_ids": [
12,
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10751
],
"title": "Maleficent: Mistress of Evil",
"vote_average": 7.2,
"overview": "Maleficent and her goddaughter Aurora begin to question the complex family ties that bind them as they are pulled in different directions by impending nuptials, unexpected allies, and dark new forces at play.",
"release_date": "2019-10-18"
},
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"video": false,
"poster_path": "/4E2lyUGLEr3yH4q6kJxPkQUhX7n.jpg",
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"adult": false,
"backdrop_path": "/iGnCzXEx0cFlUbpyAMeHwHWhPhx.jpg",
"original_language": "ja",
"original_title": "ワンピーススタンピード",
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28,
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16
],
"title": "One Piece: Stampede",
"vote_average": 7.5,
"overview": "One Piece: Stampede is a stand-alone film that celebrates the anime's 20th Anniversary and takes place outside the canon of the \"One Piece\" TV series. Monkey D. Luffy and his Straw Hat pirate crew are invited to a massive Pirate Festival that brings many of the most iconic characters from throughout the franchise to participate in competition with the Straw Hats to find Roger's treasure. It also pits the Straw Hats against a new enemy named Bullet, a former member of Roger's crew.",
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},
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27
],
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},
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},
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],
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},
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}
],
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"dates": {
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},
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}
每次我尝试将数据填充到布局（wheelview）时，它什么都不显示。我意识到这里可能存在竞争状况，但不确定如何解决。如果有用，这里是我正在使用的库的链接（wheelview）：https://github.com/LukeDeighton/WheelView
您的getMovieData()返回空列表，因为enqueue是异步的。这就是为什么您的视图中没有填充数据的原因。
尝试使用LiveData。
class MainActivityViewModel : ViewModel() {
val movieLiveList: MutableLiveData<ArrayList<MovieDataModel>> = MutableLiveData()
...
fun getMovieData() {
val call = movieService.getCurrentlyPlayingMovies(API_KEY)
val movieList = ArrayList<MovieDataModel>(10)
call.enqueue(object : Callback<MovieDataResponse> {
override fun onResponse(call: Call<MovieDataResponse>, response: Response<MovieDataResponse>) {
for (i in 0 until 10) {
movieList.add(response.body()?.results?.get(i)!!)
}
movieLiveList.postValue(movieList)
}
override fun onFailure(call: Call<MovieDataResponse>, t: Throwable) {
}
})
}
}
然后在Activity中观察实时数据并相应地更新列表。
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView(this, R.layout.activity_main)
val mainActivityViewModel = ViewModelProviders.of(this).get(MainActivityViewModel::class.java)
binding.viewModel = mainActivityViewModel
val movieList = arrayListOf<MovieDataModel>()
val movieAdapter = MovieAdapter(movieList, this)
binding.wheelview.adapter = movieAdapter
mainActivityViewModel.movieLiveList.observe(this, Observer { movies ->
movieList = movies
movieAdapter.notifyDataSetChanged()
})
}