added mock flows/suspend for prototyping in viewmodels

Author: johsoe

app/src/main/java/com/monstarlab/features/sample/SampleFragment.kt

@@ -7,6 +7,8 @@ import com.monstarlab.base.BaseFragment
 import com.monstarlab.databinding.FragmentSampleBinding
 import com.monstarlab.extensions.collectFlow
 import com.monstarlab.extensions.viewBinding
+import kotlinx.coroutines.flow.collect
+import kotlinx.coroutines.flow.combine
 
 class SampleFragment : BaseFragment(R.layout.fragment_sample) {
 
@@ -21,8 +23,14 @@ class SampleFragment : BaseFragment(R.layout.fragment_sample) {
             binding.valueTextView.text = "Clicked $clicks times"
         }
 
+        collectFlow(viewModel.textFlow) { newText ->
+            binding.asyncTextView.text = newText
+        }
+
         binding.theButton.setOnClickListener {
             viewModel.clickedButton()
         }
+
+        viewModel.fetchString()
     }
 }

app/src/main/java/com/monstarlab/features/sample/SampleViewModel.kt

@@ -1,17 +1,42 @@
 package com.monstarlab.features.sample
 
 import androidx.lifecycle.ViewModel
-import kotlinx.coroutines.flow.MutableStateFlow
+import androidx.lifecycle.viewModelScope
+import com.monstarlab.extensions.combineFlows
+import com.monstarlab.mock.MockFlows
+import com.monstarlab.mock.MockSuspends
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
 import javax.inject.Inject
 
 class SampleViewModel @Inject constructor(
 
 ): ViewModel() {
 
     val clickFlow: MutableStateFlow<Int> = MutableStateFlow(0)
+    val textFlow: MutableStateFlow<String> = MutableStateFlow("Nothing yet")
 
     fun clickedButton() {
         clickFlow.value++
     }
 
+    fun fetchString() {
+        viewModelScope.combineFlows(MockFlows.mockString(), MockFlows.mockFlag()) { text, flag ->
+            textFlow.value = "text: $text - flag: $flag"
+        }
+
+
+        MockFlows.mockString()
+                .onEach { result -> textFlow.value = result }
+                .catch { _ -> /* Do something with the exception */ }
+                .launchIn(viewModelScope)
+
+        viewModelScope.launch {
+            val result = withContext(Dispatchers.IO) { MockSuspends.fetchString() }
+            textFlow.value = result
+        }
+    }
+
 }

app/src/main/java/com/monstarlab/mock/MockFlows.kt

@@ -0,0 +1,21 @@
+package com.monstarlab.mock
+
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+
+object MockFlows {
+
+    fun mockString(): Flow<String> = flow {
+        delay(2000)
+        emit("Hello world from Flow")
+    }
+
+    fun mockFlag(): Flow<Boolean> = flow {
+        delay(1000)
+        emit(false)
+        delay(2000)
+        emit(true)
+    }
+
+}

app/src/main/java/com/monstarlab/mock/MockSuspends.kt

@@ -0,0 +1,12 @@
+package com.monstarlab.mock
+
+import kotlinx.coroutines.delay
+
+object MockSuspends {
+
+    suspend fun fetchString(): String {
+        delay(5000)
+        return "Hello world from suspend"
+    }
+
+}

app/src/main/res/layout/fragment_sample.xml

@@ -40,4 +40,15 @@
         android:layout_height="wrap_content" />
 
 
+    <TextView
+        android:id="@+id/asyncTextView"
+        app:layout_constraintTop_toBottomOf="@id/theButton"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        android:layout_marginTop="48dp"
+        android:gravity="center"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content" />
+
+
 </androidx.constraintlayout.widget.ConstraintLayout>