LiveData configuration change 시 데이터 한번 더 발행 되는 행위 Event 객체로 처리하게 수정

Author: sport0102

app/src/main/java/com/study/myapplication/base/BaseViewModel.kt

@@ -3,19 +3,17 @@ package com.study.myapplication.base
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
+import com.study.myapplication.ui.Event
 import io.reactivex.disposables.CompositeDisposable
 import io.reactivex.disposables.Disposable
 
 abstract class BaseViewModel : ViewModel() {
 
-    protected val _isDataLoading = MutableLiveData(true)
-    val isDataLoading: LiveData<Boolean> get() = _isDataLoading
+    protected val _isDataLoading = MutableLiveData(Event(true))
+    val isDataLoading: LiveData<Event<Boolean>> get() = _isDataLoading
 
-    protected val _isDataLoadingError = MutableLiveData(false)
-    val isDataLoadingError: LiveData<Boolean> get() = _isDataLoadingError
-
-    protected val _toastMessage = MutableLiveData<String>()
-    val toastMessage: LiveData<String> get() = _toastMessage
+    protected val _isDataLoadingError = MutableLiveData(Event(false))
+    val isDataLoadingError: LiveData<Event<Boolean>> get() = _isDataLoadingError
 
     private val compositeDisposable = CompositeDisposable()
 

app/src/main/java/com/study/myapplication/ui/Event.kt

@@ -0,0 +1,24 @@
+package com.study.myapplication.ui
+
+open class Event<out T>(private val content: T) {
+
+    private var hasBeenHandled = false
+        private set
+
+    /**
+     * Returns the content and prevents its use again.
+     */
+    fun getContentIfNotHandled(): T? {
+        return if (hasBeenHandled) {
+            null
+        } else {
+            hasBeenHandled = true
+            content
+        }
+    }
+
+    /**
+     * Returns the content, even if it's already been handled.
+     */
+    fun peekContent(): T = content
+}

app/src/main/java/com/study/myapplication/ui/MainActivity.kt

@@ -4,6 +4,7 @@ import android.annotation.SuppressLint
 import android.content.Intent
 import android.net.Uri
 import android.os.Bundle
+import androidx.lifecycle.Observer
 import com.study.myapplication.BR
 import com.study.myapplication.R
 import com.study.myapplication.api.model.MovieResponse
@@ -38,12 +39,21 @@ class MainActivity : BaseActivity<ActivityMainBinding, MainViewModel>(R.layout.a
                         )
                     }
                 ) {}
+            // 검색 버튼 처리
             mainBtnSearch.setOnClickListener {
                 viewModel.searchKeyword.value?.let {
                     publishSubject.onNext(it)
                 }
             }
         }
+        // 데이터 로딩 에러 처리
+        viewModel.isDataLoadingError.observe(this, Observer {
+            it.getContentIfNotHandled()?.let {isError->
+                if(isError){
+                   toastM(getString(R.string.main_toast_error_network))
+                }
+            }
+        })
     }
 
     @SuppressLint("CheckResult")

app/src/main/java/com/study/myapplication/ui/MainViewModel.kt

@@ -7,8 +7,6 @@ import com.study.myapplication.base.BaseViewModel
 import com.study.myapplication.source.NaverRepository
 import io.reactivex.android.schedulers.AndroidSchedulers
 import io.reactivex.schedulers.Schedulers
-import io.reactivex.subjects.BehaviorSubject
-import javax.security.auth.Subject
 
 class MainViewModel(private val naverRepository: NaverRepository) : BaseViewModel() {
 
@@ -20,17 +18,19 @@ class MainViewModel(private val naverRepository: NaverRepository) : BaseViewMode
         searchKeyword.value = ""
     }
 
-    fun getMovieList(query : String) {
+    fun getMovieList(query: String) {
         naverRepository.getMovieList(query)?.let { single ->
             addDisposable(
                 single
                     .subscribeOn(Schedulers.io())
                     .observeOn(AndroidSchedulers.mainThread())
                     .subscribe({
-                        _movieList.postValue(it.items)
-                        clearKeyword()
+                        _isDataLoadingError.value = Event(true)
+//                        _isDataLoadingError.value = Event(false)
+//                        _movieList.postValue(it.items)
+//                        clearKeyword()
                     }, {
-
+                        _isDataLoadingError.value = Event(true)
                     })
             )
         }

app/src/main/res/values/strings.xml

@@ -1,4 +1,5 @@
 <resources>
     <string name="app_name">My Application</string>
     <string name="main_search">검색</string>
+    <string name="main_toast_error_network">데이터를 가져올 수 없습니다</string>
 </resources>