我對 MVVM 很陌生，我很樂意得到一些幫助。它是非常基礎的專案，只是為了了解如何在 MVVM 中完成作業。
因此，一旦應用程式啟動，它就會用 API 中的所有員工填充 recyclerView。我有一個浮動操作按鈕，當我按下它時，會打開一個帶有 edittext 的警報對話框，當我輸入一個數字時，我想根據他的 ID 從 API 中獲取特定員工并更新 recyclerview 以便它顯示只有1名員工。
問題是：
當我輸入一個 ID 并按搜索時，服務器通過它的 ID 為我找到一個特定的員工并且它作業正常，但是當我再次搜索一個特定的員工時，我沒有在 logcat 中獲得員工的詳細資訊，就像它沒有不要在服務器中搜索它（我沒有從 logcat 收到任何錯誤或失敗的日志）。
我不確定我是否像它應該的那樣實作了 observables 和 MVVM 模式，所以如果你有任何反饋，我很樂意聽到它。
我正在使用這個虛擬 API - https://dummy.restapiexample.com/
這是員工模型：
data class Employee (
@SerializedName("employee_name")
val employeeName:String,
@SerializedName("employee_salary")
val employeeSalary: String,
@SerializedName("employee_age")
val employeeAge: Int,
@SerializedName("id")
val employeeID: Int
)
data class EmployeesListResult(
@SerializedName("data")
val getEmployeesListResult : List<Employee>,
)
data class SingleEmployeeListResult(
@SerializedName("data")
val getSingleEmployeesListResult : Employee
)
這是 APIRequest 物件：
object APIRequest {
val baseUrl : String = "https://dummy.restapiexample.com/api/v1/"
var retrofit: Retrofit = Retrofit.Builder()
.baseUrl(baseUrl)
.addConverterFactory(GsonConverterFactory.create())
.build()
val retrofitCallGetList : APICallRequest = retrofit.create(APICallRequest::class.java)
}
interface APICallRequest{
@GET("employees")
fun callEmployeeList() : Call<EmployeesListResult>
@GET("employee/{id}")
fun callSpecificEmployee(@Path(value = "id", encoded = false) key: Int, ): Call<SingleEmployeeListResult>
}
這是 MainRepository 類：
class MainRepository {
val mutableListLiveData = MutableLiveData<List<Employee>>()
val mutableSingleLiveData = MutableLiveData<Employee>()
fun getEmployeeListFromAPI(): MutableLiveData<List<Employee>> {
val apiRequest: APICallRequest = APIRequest.retrofitCallGetList
apiRequest.callEmployeeList().enqueue(object : Callback<EmployeesListResult?> {
override fun onResponse(
call: Call<EmployeesListResult?>,
response: Response<EmployeesListResult?>
) {
if (response.isSuccessful) {
mutableListLiveData.value = response.body()?.getEmployeesListResult
Log.e("onResponse", "Success!")
Log.e("Response:", "${response.body()}")
}
}
override fun onFailure(call: Call<EmployeesListResult?>, t: Throwable) {
Log.e("onFailure", "Failed getting list: ${t.message}")
}
})
return mutableListLiveData
}
fun getSpecificEmployee(employeeID: Int): MutableLiveData<Employee> {
val apiRequest: APICallRequest = APIRequest.retrofitCallGetList
apiRequest.callSpecificEmployee(employeeID).enqueue(object : Callback<SingleEmployeeListResult?> {
override fun onResponse(
call: Call<SingleEmployeeListResult?>,
response: Response<SingleEmployeeListResult?>
) {
if (response.isSuccessful) {
mutableSingleLiveData.value = response.body()?.getSingleEmployeesListResult
Log.e("Single onResponse", "Success!")
Log.e("Response:", "${response.body()}")
}
}
override fun onFailure(call: Call<SingleEmployeeListResult?>, t: Throwable) {
Log.e("Single onResponse FAIL", "FAIL! ${t.message}")
}
})
return mutableSingleLiveData
}
這是主視圖模型：
class MainViewModel : ViewModel() {
private var employeeMutableData : MutableLiveData<List<Employee>>? = null
private var specificEmployeeMutableData : MutableLiveData<Employee>? = null
fun getEmployeeListFromRepo() : LiveData<List<Employee>>{
if (employeeMutableData == null){
employeeMutableData = MainRepository().getEmployeeListFromAPI()
}
return employeeMutableData as LiveData<List<Employee>>
}
fun getSpecificEmployee(employeeID : Int) : LiveData<Employee> {
if (specificEmployeeMutableData == null){
specificEmployeeMutableData = MainRepository().getSpecificEmployee(employeeID)
}
return specificEmployeeMutableData as LiveData<Employee>
}
}
MainActivity 類：
class MainActivity : AppCompatActivity() {
private val mainViewModel : MainViewModel by viewModels()
private lateinit var recyclerView: RecyclerView
private lateinit var mainAdapter: MainRecyclerViewAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
initRecycler()
val actionButton = findViewById<FloatingActionButton>(R.id.actionButton)
actionButton.setOnClickListener(View.OnClickListener {
searchEmployeeByIdDialog()
})
mainViewModel.getEmployeeListFromRepo().observe(this,object : Observer<List<Employee>> {
override fun onChanged(theListOfEmployees: List<Employee>) {
mainAdapter = MainRecyclerViewAdapter(theListOfEmployees)
recyclerView.adapter = mainAdapter
}
})
} // End of OnCreate
private fun initRecycler() {
recyclerView = findViewById<RecyclerView>(R.id.mainRecyclerView)
recyclerView.setHasFixedSize(true)
recyclerView.layoutManager = GridLayoutManager(this@MainActivity,2)
}
private fun searchEmployeeByIdDialog(){
val editTextForDialog = EditText(this)
editTextForDialog.maxLines = 1
editTextForDialog.setPadding(10)
editTextForDialog.inputType = InputType.TYPE_CLASS_NUMBER
val alertDialog = AlertDialog.Builder(this)
alertDialog.setTitle("Employee Search")
alertDialog.setMessage("What employee ID do you want to look for ?")
alertDialog.setView(editTextForDialog)
.setPositiveButton("Search", DialogInterface.OnClickListener { dialogInterface: DialogInterface?, i: Int ->
if (editTextForDialog.text.isNotEmpty()){
mainViewModel.getSpecificEmployee(editTextForDialog.text.toString().toInt()).observe(this,object : Observer<Employee?> {
override fun onChanged(t: Employee?) {
if (t != null) {
val list = listOf(t)
mainAdapter.updateEmployeeList(list)
}
}
})
}else{
Toast.makeText(this,"Please enter employee ID",Toast.LENGTH_SHORT).show()
}
})
.setNegativeButton("Cancel", DialogInterface.OnClickListener { dialogInterface, i ->
dialogInterface.dismiss()
})
.show()
}
}
最后， MainRecyclerViewAdapter 類：
class MainRecyclerViewAdapter(var employeeList: List<Employee>) : RecyclerView.Adapter<MainRecyclerViewAdapter.EmployeesHolder>() {
inner class EmployeesHolder(var itemView : View) : RecyclerView.ViewHolder(itemView){
fun bindData(employee : Employee){
val nameTextView = itemView.findViewById<TextView>(R.id.nameTextView)
val ageTextView = itemView.findViewById<TextView>(R.id.ageTextView)
val salaryTextView = itemView.findViewById<TextView>(R.id.salaryTextView)
nameTextView.text = employee.employeeName
ageTextView.text = employee.employeeAge.toString()
salaryTextView.text = employee.employeeSalary
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): EmployeesHolder {
return EmployeesHolder(LayoutInflater.from(parent.context).inflate(R.layout.recyclerview_row,parent,false))
}
override fun onBindViewHolder(holder: EmployeesHolder, position: Int) {
holder.bindData(employeeList[position])
}
override fun getItemCount(): Int {
return employeeList.size
}
fun updateEmployeeList(newList: List<Employee>) {
this.employeeList = newList
notifyDataSetChanged()
}
}
非常感謝你！
uj5u.com熱心網友回復：
在您的 MainViewModel 實作中，關于您如何實作您的getSpecificEmployee(...)方法，有些東西對我來說很突出。
它目前的實作方式，第一次搜索特定員工時，specificEmployeeMutableData實時資料將為空，因此會呼叫相關的存盤庫方法。
但是對于隨后嘗試獲取特定員工的時間，specificEmployeeMutableData將不再為空，這意味著它不會觸發存盤庫中的 API 呼叫。
這就是為什么在您的日志中，似乎什么也沒發生……因為什么都沒有。
一個快速補丁可能是洗掉空檢查，并在每次需要獲取特定員工時呼叫存盤庫。
fun getSpecificEmployee(employeeID : Int) : LiveData<Employee> {
return MainRepository().getSpecificEmployee(employeeID) as LiveData<Employee>
}
轉載請註明出處，本文鏈接：https://www.uj5u.com/caozuo/384279.html
標籤：安卓 接口 科特林 android-recyclerview android-mvvm
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