Merge pull request #12 from Jintin/feature/state

add state flow type support
Jintin · Dec 20, 2020 · 081ba16 · 081ba16
2 parents 2bcca16 + 4417ffb
commit 081ba16
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Showing 7 changed files with 81 additions and 13 deletions.
diff --git a/.idea/inspectionProfiles/Project_Default.xml b/.idea/inspectionProfiles/Project_Default.xml
diff --git a/app/src/main/java/com/jintin/fancylocation/app/MainActivity.kt b/app/src/main/java/com/jintin/fancylocation/app/MainActivity.kt
@@ -19,11 +19,12 @@ class MainActivity : AppCompatActivity() {
     companion object {
         const val TYPE_LIVEDATA = 0
         const val TYPE_FLOW = 1
+        const val TYPE_STATEFLOW = 2
     }
 
-    private val mainViewModel by viewModels<MainViewModel>()
+    private val viewModel by viewModels<MainViewModel>()
 
-    private val type = TYPE_FLOW
+    private val type = TYPE_STATEFLOW
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -44,30 +45,37 @@ class MainActivity : AppCompatActivity() {
         when (type) {
             TYPE_LIVEDATA -> liveDataObserve()
             TYPE_FLOW -> flowObserve()
+            TYPE_STATEFLOW -> stateFlowObserve()
         }
     }
 
     @RequiresPermission(anyOf = [Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION])
     private fun flowObserve() {
         lifecycleScope.launch {
             @Suppress("EXPERIMENTAL_API_USAGE")
-            mainViewModel.locationFlow.get().collect {
-                updateUI(it)
-            }
+            viewModel.locationFlow.get().collect(::updateUI)
         }
     }
 
     @RequiresPermission(anyOf = [Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION])
-    private fun liveDataObserve() {
-        mainViewModel.locationLiveData.observe(this) {
-            updateUI(it)
+    private fun stateFlowObserve() {
+        lifecycleScope.launch {
+            viewModel.locationStateFlow.start()
+            viewModel.locationStateFlow.value.collect(::updateUI)
         }
     }
 
+    @RequiresPermission(anyOf = [Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION])
+    private fun liveDataObserve() {
+        viewModel.locationLiveData.observe(this, ::updateUI)
+    }
+
     private fun updateUI(locationData: LocationData) {
         findViewById<TextView>(R.id.location).text = when (locationData) {
+            LocationData.Init -> "Init state"
+            LocationData.Loading -> "Start loading"
+            LocationData.Fail -> "Fail to get location"
             is LocationData.Success -> locationData.location.toString()
-            is LocationData.Fail -> "Fail to get location"
         }
     }
 }
diff --git a/app/src/main/java/com/jintin/fancylocation/app/MainViewModel.kt b/app/src/main/java/com/jintin/fancylocation/app/MainViewModel.kt
@@ -3,10 +3,7 @@ package com.jintin.fancylocation.app
 import android.app.Application
 import androidx.lifecycle.AndroidViewModel
 import com.google.android.gms.location.LocationRequest
-import com.jintin.fancylocation.ILocationProvider
-import com.jintin.fancylocation.LocationProvider
-import com.jintin.fancylocation.asFlow
-import com.jintin.fancylocation.asLiveData
+import com.jintin.fancylocation.*
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 
 class MainViewModel(application: Application) : AndroidViewModel(application) {
@@ -19,6 +16,7 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
 
 //    @ExperimentalCoroutinesApi
 //    val locationFlow = LocationFlow(application, locationRequest)
+//    val locationStateFlow = LocationFlow(application, locationRequest)
 //    val locationLiveData = LocationLiveData(application, locationRequest)
 
     // we can also provide custom vendor by create your own LocationProvider
@@ -27,4 +25,5 @@ class MainViewModel(application: Application) : AndroidViewModel(application) {
     @ExperimentalCoroutinesApi
     val locationFlow = locationProvider.asFlow()
     val locationLiveData = locationProvider.asLiveData()
+    val locationStateFlow = locationProvider.asStateFlow()
 }
diff --git a/lib/src/main/java/com/jintin/fancylocation/LocationData.kt b/lib/src/main/java/com/jintin/fancylocation/LocationData.kt
@@ -3,6 +3,8 @@ package com.jintin.fancylocation
 import android.location.Location
 
 sealed class LocationData {
+    object Init : LocationData()
+    object Loading : LocationData()
     data class Success(val location: Location) : LocationData()
     object Fail : LocationData()
 }
diff --git a/lib/src/main/java/com/jintin/fancylocation/LocationExtension.kt b/lib/src/main/java/com/jintin/fancylocation/LocationExtension.kt
@@ -9,4 +9,8 @@ fun ILocationProvider.asLiveData(): LocationLiveData {
 @ExperimentalCoroutinesApi
 fun ILocationProvider.asFlow(): LocationFlow {
     return LocationFlow(this)
+}
+
+fun ILocationProvider.asStateFlow(): LocationStateFlow {
+    return LocationStateFlow(this)
 }
diff --git a/lib/src/main/java/com/jintin/fancylocation/LocationFlow.kt b/lib/src/main/java/com/jintin/fancylocation/LocationFlow.kt
@@ -23,6 +23,7 @@ class LocationFlow(
 
     @RequiresPermission(anyOf = [Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION])
     fun get(): Flow<LocationData> = channelFlow {
+        channel.sendBlocking(LocationData.Loading)
         locationProvider.requestLocationUpdates(object : ILocationObserver {
             override fun onLocationResult(location: Location) {
                 channel.sendBlocking(LocationData.Success(location))

diff --git a/lib/src/main/java/com/jintin/fancylocation/LocationStateFlow.kt b/lib/src/main/java/com/jintin/fancylocation/LocationStateFlow.kt
@@ -0,0 +1,48 @@
+package com.jintin.fancylocation
+
+import android.Manifest
+import android.content.Context
+import android.location.Location
+import androidx.annotation.RequiresPermission
+import com.google.android.gms.location.LocationRequest
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.suspendCancellableCoroutine
+import kotlin.coroutines.coroutineContext
+
+class LocationStateFlow(
+    private val locationProvider: ILocationProvider
+) {
+    private val _value = MutableStateFlow<LocationData>(LocationData.Init)
+    val value: StateFlow<LocationData> get() = _value
+
+    constructor(
+        context: Context,
+        locationRequest: LocationRequest
+    ) : this(LocationProvider(context, locationRequest))
+
+    @RequiresPermission(anyOf = [Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION])
+    suspend fun start() {
+        _value.value = LocationData.Loading
+        locationProvider.requestLocationUpdates(object : ILocationObserver {
+            override fun onLocationResult(location: Location) {
+                _value.value = LocationData.Success(location)
+            }
+
+            override fun onLocationFailed() {
+                _value.value = LocationData.Fail
+            }
+        })
+        with(CoroutineScope(coroutineContext)) { // spawns and uses parent scope!
+            launch {
+                suspendCancellableCoroutine<Unit> {
+                    it.invokeOnCancellation {
+                        locationProvider.removeLocationUpdates()
+                    }
+                }
+            }
+        }
+    }
+}