我是Kotlin的初学者。我需要将来自Activity的可变参数发送给改造调用。
这是我致电“创建明细活动”
override fun onCreate(savedInstanceState: Bundle?) {
//...
val id = intent.getStringExtra("id")
// Get the ViewMode
val mModel = ViewModelProviders.of(this).get(myObjectViewModel::class.java)
//Create the observer which updates the UI.
val myObjectByIdObserver = Observer<MyObject> { myObject->
//...
}
//Observe the LiveData, passing in this activity as the LifecycleOwner and the observer.
mModel.getObjectById.observe(this, myObjectByIdObserver)
}
在这里插入值硬编码,我需要从上一个活动中接收到的参数。
class MyObjectViewModel : ViewModel() {
//this is the data that we will fetch asynchronously
var myObject: MutableLiveData<MyObject>? = null
val getMyObjectById: LiveData<MyObject>
get() {
if (myObject == null) {
myObject = MutableLiveData()
loadMyObjectById()
}
return myObject as MutableLiveData<MyObject>
}
private fun loadMyObjectById() {
val retrofit = Retrofit.Builder()
.baseUrl(Api.BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.build()
val api = retrofit.create(Api::class.java)
val call = api.myObjectById(100)
call.enqueue(object : Callback<MyObject> {
override fun onResponse(call: Call<MyObject>, response: Response<MyObject>) {
myObject!!.value = response.body()
}
override fun onFailure(call: Call<MyObject>, t: Throwable) {
var tt = t
}
})
}
我的API:
interface Api {
companion object {
const val BASE_URL = "https://.../"
}
@GET("myObjects/{id}")
fun myObjectById(@Path("id") id: Int?): Call<MyObject>
}
答案 0 :(得分:1)
您可以通过``@ Query`''注释来完成此操作。
interface Api {
companion object {
const val BASE_URL = "https://.../"
}
@GET("myObjects/{id}")
fun myObjectById(@Path("id") id: Int?, @Query("a_param") aParam: String?): Call<MyObject>
}
已编辑。我完全误解了你的意图。
您所需要的似乎像ViewModelProvider.NewInstanceFactory
class MyObjectViewModel(val id: Int): ViewModel() {
class Factory(val id: Int) : ViewModelProvider.NewInstanceFactory() {
override fun <T : ViewModel?> create(modelClass: Class<T>): T {
return MyObjectViewModel(id) as T
}
}
}
然后
val myViewModel = ViewModelProviders
.of(this, MyObjectViewModel.Factory(id))
.get(MyObjectViewModel::class.java)