Introduce Hilt dependency injection

Uses Hilt to get the database initialization off of the
main thread.

The initial introduction always has a disproportionate
fan-out of boilerplate. In this case, all entry points which
were using UIViewModel needed to be annotated in order to let
the code gen know that they needed to support it.

The PacketRepository is injected into things via the main
thread (e.g., the MeshService) but due to the lazy declaration,
the database isn't hydrated until the DAO is access while on an
IO thread.

app/build.gradle

@@ -2,6 +2,7 @@ apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-parcelize'
 apply plugin: 'kotlinx-serialization'
+apply plugin: 'dagger.hilt.android.plugin'
 apply plugin: 'com.google.gms.google-services'
 apply plugin: 'com.github.triplet.play'
 apply plugin: 'de.mobilej.unmock'
@@ -135,7 +136,9 @@ dependencies {
     implementation 'androidx.lifecycle:lifecycle-extensions:2.2.0'
     implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.4.0'
     implementation "androidx.room:room-runtime:$room_version"
+    implementation "com.google.dagger:hilt-android:$hilt_version"
     kapt "androidx.room:room-compiler:$room_version"
+    kapt "com.google.dagger:hilt-compiler:$hilt_version"
 
 
     // optional - Kotlin Extensions and Coroutines support for Room
@@ -200,3 +203,7 @@ dependencies {
 
     implementation project(':geeksville-androidlib')
 }
+
+kapt {
+    correctErrorTypes true
+}

app/src/main/java/com/geeksville/mesh/ApplicationModule.kt

@@ -0,0 +1,18 @@
+package com.geeksville.mesh
+
+import android.app.Application
+import android.content.Context
+import android.content.SharedPreferences
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+
+@InstallIn(SingletonComponent::class)
+@Module
+object ApplicationModule {
+    @Provides
+    fun provideSharedPreferences(application: Application): SharedPreferences {
+        return application.getSharedPreferences("ui-prefs", Context.MODE_PRIVATE)
+    }
+}

app/src/main/java/com/geeksville/mesh/MainActivity.kt

@@ -62,6 +62,7 @@ import com.google.android.material.snackbar.Snackbar
 import com.google.android.material.tabs.TabLayoutMediator
 import com.vorlonsoft.android.rate.AppRate
 import com.vorlonsoft.android.rate.StoreType
+import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
@@ -123,6 +124,7 @@ eventually:
 
 val utf8 = Charset.forName("UTF-8")
 
+@AndroidEntryPoint
 class MainActivity : AppCompatActivity(), Logging,
     ActivityCompat.OnRequestPermissionsResultCallback {
 

app/src/main/java/com/geeksville/mesh/MeshUtilApplication.kt

@@ -7,8 +7,13 @@ import com.geeksville.android.GeeksvilleApplication
 import com.geeksville.android.Logging
 import com.geeksville.util.Exceptions
 import com.google.firebase.crashlytics.FirebaseCrashlytics
+import dagger.hilt.android.HiltAndroidApp
 
-class MeshUtilApplication : GeeksvilleApplication() {
+// NOTE: This is a workaround since the Hilt Gradle plugin doesn't support constructors with default parameters
+open class GeeksvilleApplicationWrapper : GeeksvilleApplication()
+
+@HiltAndroidApp
+class MeshUtilApplication : GeeksvilleApplicationWrapper() {
 
     override fun onCreate() {
         super.onCreate()

app/src/main/java/com/geeksville/mesh/database/DatabaseModule.kt

@@ -0,0 +1,29 @@
+package com.geeksville.mesh.database
+
+import android.app.Application
+import androidx.room.Room
+import com.geeksville.mesh.database.dao.PacketDao
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+
+@InstallIn(SingletonComponent::class)
+@Module
+class DatabaseModule {
+    @Provides
+    fun provideDatabase(application: Application): MeshtasticDatabase {
+        return Room.databaseBuilder(
+            application.applicationContext,
+            MeshtasticDatabase::class.java,
+            "meshtastic_database"
+        )
+            .fallbackToDestructiveMigration()
+            .build()
+    }
+
+    @Provides
+    fun providePacketDao(database: MeshtasticDatabase): PacketDao {
+        return database.packetDao()
+    }
+}

app/src/main/java/com/geeksville/mesh/database/MeshtasticDatabase.kt

@@ -1,8 +1,6 @@
 package com.geeksville.mesh.database
 
-import android.content.Context
 import androidx.room.Database
-import androidx.room.Room
 import androidx.room.RoomDatabase
 import com.geeksville.mesh.database.dao.PacketDao
 import com.geeksville.mesh.database.entity.Packet
@@ -10,27 +8,4 @@ import com.geeksville.mesh.database.entity.Packet
 @Database(entities = [Packet::class], version = 1, exportSchema = false)
 abstract class MeshtasticDatabase : RoomDatabase() {
     abstract fun packetDao(): PacketDao
-
-    companion object {
-        @Volatile
-        private var INSTANCE: MeshtasticDatabase? = null
-
-        fun getDatabase(
-            context: Context
-        ): MeshtasticDatabase {
-            return INSTANCE ?: synchronized(this) {
-                val instance = Room.databaseBuilder(
-                    context.applicationContext,
-                    MeshtasticDatabase::class.java,
-                    "meshtastic_database"
-                )
-                    .fallbackToDestructiveMigration()
-                    .build()
-                INSTANCE = instance
-
-                instance
-            }
-        }
-    }
-
 }

app/src/main/java/com/geeksville/mesh/database/PacketRepository.kt

@@ -1,24 +1,34 @@
 package com.geeksville.mesh.database
 
-import androidx.lifecycle.LiveData
 import com.geeksville.mesh.database.dao.PacketDao
 import com.geeksville.mesh.database.entity.Packet
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.withContext
+import javax.inject.Inject
 
-class PacketRepository(private val packetDao : PacketDao) {
+class PacketRepository @Inject constructor(private val packetDaoLazy: dagger.Lazy<PacketDao>) {
-    val allPackets : LiveData<List<Packet>> = packetDao.getAllPacket(MAX_ITEMS)
+    private val packetDao by lazy {
-    val allPacketsInReceiveOrder : Flow<List<Packet>> = packetDao.getAllPacketsInReceiveOrder(MAX_ITEMS)
+        packetDaoLazy.get()
+    }
 
-    suspend fun insert(packet: Packet) {
+    suspend fun getAllPackets(): Flow<List<Packet>> = withContext(Dispatchers.IO) {
+        packetDao.getAllPacket(MAX_ITEMS)
+    }
+
+    suspend fun getAllPacketsInReceiveOrder(): Flow<List<Packet>> = withContext(Dispatchers.IO) {
+        packetDao.getAllPacketsInReceiveOrder(MAX_ITEMS)
+    }
+
+    suspend fun insert(packet: Packet) = withContext(Dispatchers.IO) {
         packetDao.insert(packet)
     }
 
-    suspend fun deleteAll() {
+    suspend fun deleteAll() = withContext(Dispatchers.IO) {
         packetDao.deleteAll()
     }
 
     companion object {
         private const val MAX_ITEMS = 500
     }
-
 }

app/src/main/java/com/geeksville/mesh/database/dao/PacketDao.kt

@@ -1,6 +1,5 @@
 package com.geeksville.mesh.database.dao
 
-import androidx.lifecycle.LiveData
 import androidx.room.Dao
 import androidx.room.Insert
 import androidx.room.Query
@@ -11,7 +10,7 @@ import kotlinx.coroutines.flow.Flow
 interface PacketDao {
 
     @Query("Select * from packet order by received_date desc limit 0,:maxItem")
-    fun getAllPacket(maxItem: Int): LiveData<List<Packet>>
+    fun getAllPacket(maxItem: Int): Flow<List<Packet>>
 
     @Query("Select * from packet order by received_date asc limit 0,:maxItem")
     fun getAllPacketsInReceiveOrder(maxItem: Int): Flow<List<Packet>>

app/src/main/java/com/geeksville/mesh/model/UIState.kt

@@ -7,18 +7,20 @@ import android.net.Uri
 import android.os.RemoteException
 import android.view.Menu
 import androidx.core.content.edit
-import androidx.lifecycle.AndroidViewModel
-import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.geeksville.android.Logging
 import com.geeksville.mesh.*
-import com.geeksville.mesh.database.MeshtasticDatabase
 import com.geeksville.mesh.database.PacketRepository
 import com.geeksville.mesh.database.entity.Packet
 import com.geeksville.mesh.service.MeshService
 import com.geeksville.mesh.ui.positionToMeter
+import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -26,6 +28,7 @@ import java.io.BufferedWriter
 import java.io.FileWriter
 import java.text.SimpleDateFormat
 import java.util.*
+import javax.inject.Inject
 import kotlin.math.roundToInt
 
 /// Given a human name, strip out the first letter of the first three words and return that as the initials for
@@ -51,20 +54,25 @@ fun getInitials(nameIn: String): String {
     return initials.take(nchars)
 }
 
-class UIViewModel(private val app: Application) : AndroidViewModel(app), Logging {
+@HiltViewModel
+class UIViewModel @Inject constructor(
+    private val app: Application,
+    private val repository: PacketRepository,
+    private val preferences: SharedPreferences
+) : ViewModel(), Logging {
 
-    private val repository: PacketRepository
+    private val _allPacketState = MutableStateFlow<List<Packet>>(emptyList())
-
+    val allPackets: StateFlow<List<Packet>> = _allPacketState
-    val allPackets: LiveData<List<Packet>>
 
     init {
-        val packetsDao = MeshtasticDatabase.getDatabase(app).packetDao()
+        viewModelScope.launch {
-        repository = PacketRepository(packetsDao)
+            repository.getAllPackets().collect { packets ->
-        allPackets = repository.allPackets
+                _allPacketState.value = packets
+            }
+        }
         debug("ViewModel created")
     }
 
-
     fun insertPacket(packet: Packet) = viewModelScope.launch(Dispatchers.IO) {
         repository.insert(packet)
     }
@@ -78,8 +86,6 @@ class UIViewModel(private val app: Application) : AndroidViewModel(app), Logging
             context.getSharedPreferences("ui-prefs", Context.MODE_PRIVATE)
     }
 
-    private val context: Context get() = app.applicationContext
-
     var actionBarMenu: Menu? = null
 
     var meshService: IMeshService? = null
@@ -208,7 +214,7 @@ class UIViewModel(private val app: Application) : AndroidViewModel(app), Logging
         channels.value =
             c // Must be done after calling the service, so we will will properly throw if the service failed (and therefore not cache invalid new settings)
 
-        getPreferences(context).edit(commit = true) {
+        preferences.edit(commit = true) {
             this.putString("channel-url", c.getChannelUrl().toString())
         }
     }
@@ -226,11 +232,11 @@ class UIViewModel(private val app: Application) : AndroidViewModel(app), Logging
     val bluetoothEnabled = object : MutableLiveData<Boolean>(false) {
     }
 
-    val provideLocation = object : MutableLiveData<Boolean>(getPreferences(context).getBoolean(MyPreferences.provideLocationKey, false)) {
+    val provideLocation = object : MutableLiveData<Boolean>(preferences.getBoolean(MyPreferences.provideLocationKey, false)) {
         override fun setValue(value: Boolean) {
             super.setValue(value)
 
-            getPreferences(context).edit(commit = true) {
+            preferences.edit(commit = true) {
                 this.putBoolean(MyPreferences.provideLocationKey, value)
             }
         }
@@ -246,7 +252,7 @@ class UIViewModel(private val app: Application) : AndroidViewModel(app), Logging
             ownerName.value = s
 
             // note: we allow an empty userstring to be written to prefs
-            getPreferences(context).edit(commit = true) {
+            preferences.edit(commit = true) {
                 putString("owner", s)
             }
         }
@@ -286,7 +292,7 @@ class UIViewModel(private val app: Application) : AndroidViewModel(app), Logging
                 // our device in localNodePosition.
                 var localNodePosition: MeshProtos.Position? = null
                 val dateFormat = SimpleDateFormat("yyyy-MM-dd,HH:mm:ss", Locale.getDefault())
-                repository.allPacketsInReceiveOrder.first().forEach { packet ->
+                repository.getAllPacketsInReceiveOrder().first().forEach { packet ->
                     packet.proto?.let { proto ->
                         packet.position?.let { position ->
                             if (proto.from == myNodeNum) {

app/src/main/java/com/geeksville/mesh/service/MeshService.kt

@@ -22,7 +22,6 @@ import com.geeksville.mesh.*
 import com.geeksville.mesh.MeshProtos.MeshPacket
 import com.geeksville.mesh.MeshProtos.ToRadio
 import com.geeksville.mesh.android.hasBackgroundPermission
-import com.geeksville.mesh.database.MeshtasticDatabase
 import com.geeksville.mesh.database.PacketRepository
 import com.geeksville.mesh.database.entity.Packet
 import com.geeksville.mesh.model.DeviceVersion
@@ -36,9 +35,12 @@ import com.google.android.gms.location.LocationServices
 import com.google.android.gms.location.LocationSettingsRequest
 import com.google.protobuf.ByteString
 import com.google.protobuf.InvalidProtocolBufferException
+import dagger.Lazy
+import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.*
 import kotlinx.serialization.json.Json
 import java.util.*
+import javax.inject.Inject
 import kotlin.math.absoluteValue
 import kotlin.math.max
 
@@ -49,7 +51,10 @@ import kotlin.math.max
  * Note: this service will go away once all clients are unbound from it.
  * Warning: do not override toString, it causes infinite recursion on some androids (because contextWrapper.getResources calls to string
  */
+@AndroidEntryPoint
 class MeshService : Service(), Logging {
+    @Inject
+    lateinit var packetRepository: Lazy<PacketRepository>
 
     companion object : Logging {
 
@@ -119,9 +124,6 @@ class MeshService : Service(), Logging {
     private val serviceScope = CoroutineScope(Dispatchers.IO + serviceJob)
     private var connectionState = ConnectionState.DISCONNECTED
 
-    /// A database of received packets - used only for debug log
-    private var packetRepo: PacketRepository? = null
-
     private var fusedLocationClient: FusedLocationProviderClient? = null
 
     // If we've ever read a valid region code from our device it will be here
@@ -326,9 +328,6 @@ class MeshService : Service(), Logging {
 
         info("Creating mesh service")
 
-        val packetsDao = MeshtasticDatabase.getDatabase(applicationContext).packetDao()
-        packetRepo = PacketRepository(packetsDao)
-
         // Switch to the IO thread
         serviceScope.handledLaunch {
             loadSettings() // Load our last known node DB
@@ -994,7 +993,7 @@ class MeshService : Service(), Logging {
         serviceScope.handledLaunch {
             // Do not log, because might contain PII
             // info("insert: ${packetToSave.message_type} = ${packetToSave.raw_message.toOneLineString()}")
-            packetRepo!!.insert(packetToSave)
+            packetRepository.get().insert(packetToSave)
         }
     }
 

app/src/main/java/com/geeksville/mesh/ui/AdvancedSettingsFragment.kt

@@ -6,7 +6,6 @@ import android.view.View
 import android.view.ViewGroup
 import android.view.inputmethod.EditorInfo
 import androidx.fragment.app.activityViewModels
-import androidx.lifecycle.Observer
 import com.geeksville.android.Logging
 import com.geeksville.android.hideKeyboard
 import com.geeksville.mesh.R
@@ -16,7 +15,9 @@ import com.geeksville.mesh.model.UIViewModel
 import com.geeksville.mesh.service.MeshService
 import com.geeksville.util.exceptionToSnackbar
 import com.google.android.material.snackbar.Snackbar
+import dagger.hilt.android.AndroidEntryPoint
 
+@AndroidEntryPoint
 class AdvancedSettingsFragment : ScreenFragment("Advanced Settings"), Logging {
     private val MAX_INT_DEVICE = 0xFFFFFFFF
     private var _binding: AdvancedSettingsBinding? = null

app/src/main/java/com/geeksville/mesh/ui/ChannelFragment.kt

@@ -33,6 +33,7 @@ import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.android.material.snackbar.Snackbar
 import com.google.protobuf.ByteString
 import com.google.zxing.integration.android.IntentIntegrator
+import dagger.hilt.android.AndroidEntryPoint
 import java.security.SecureRandom
 
 
@@ -51,6 +52,7 @@ fun ImageView.setOpaque() {
     imageAlpha = 255
 }
 
+@AndroidEntryPoint
 class ChannelFragment : ScreenFragment("Channel"), Logging {
 
     private var _binding: ChannelFragmentBinding? = null

app/src/main/java/com/geeksville/mesh/ui/DebugFragment.kt

@@ -6,13 +6,15 @@ import android.view.View
 import android.view.ViewGroup
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.viewModels
-import androidx.lifecycle.Observer
+import androidx.lifecycle.asLiveData
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.geeksville.mesh.R
 import com.geeksville.mesh.databinding.DebugFragmentBinding
 import com.geeksville.mesh.model.UIViewModel
+import dagger.hilt.android.AndroidEntryPoint
 
+@AndroidEntryPoint
 class DebugFragment : Fragment() {
 
     private var _binding: DebugFragmentBinding? = null
@@ -48,8 +50,8 @@ class DebugFragment : Fragment() {
         binding.closeButton.setOnClickListener {
             parentFragmentManager.popBackStack()
         }
-        model.allPackets.observe(viewLifecycleOwner, Observer { packets ->
+        model.allPackets.asLiveData().observe(viewLifecycleOwner) { packets ->
             packets?.let { adapter.setPackets(it) }
-        })
+        }
     }
 }

app/src/main/java/com/geeksville/mesh/ui/MapFragment.kt

@@ -32,8 +32,10 @@ import com.mapbox.maps.extension.style.sources.generated.GeoJsonSource
 import com.mapbox.maps.plugin.animation.MapAnimationOptions
 import com.mapbox.maps.plugin.animation.flyTo
 import com.mapbox.maps.plugin.gestures.gestures
+import dagger.hilt.android.AndroidEntryPoint
 
 
+@AndroidEntryPoint
 class MapFragment : ScreenFragment("Map"), Logging {
 
     private val model: UIViewModel by activityViewModels()

app/src/main/java/com/geeksville/mesh/ui/MessagesFragment.kt

@@ -26,6 +26,7 @@ import com.geeksville.mesh.databinding.MessagesFragmentBinding
 import com.geeksville.mesh.model.UIViewModel
 import com.geeksville.mesh.service.MeshService
 import com.google.android.material.chip.Chip
+import dagger.hilt.android.AndroidEntryPoint
 import java.text.DateFormat
 import java.util.*
 
@@ -41,6 +42,7 @@ fun EditText.on(actionId: Int, func: () -> Unit) {
     }
 }
 
+@AndroidEntryPoint
 class MessagesFragment : ScreenFragment("Messages"), Logging {
 
     private var _binding: MessagesFragmentBinding? = null

app/src/main/java/com/geeksville/mesh/ui/SettingsFragment.kt

@@ -49,6 +49,7 @@ import com.google.android.gms.location.LocationSettingsRequest
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.android.material.snackbar.Snackbar
 import com.hoho.android.usbserial.driver.UsbSerialDriver
+import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
@@ -439,6 +440,7 @@ class BTScanModel(app: Application) : AndroidViewModel(app), Logging {
 }
 
 @SuppressLint("NewApi")
+@AndroidEntryPoint
 class SettingsFragment : ScreenFragment("Settings"), Logging {
     private var _binding: SettingsFragmentBinding? = null
 

app/src/main/java/com/geeksville/mesh/ui/UsersFragment.kt

@@ -9,7 +9,6 @@ import android.view.ViewGroup
 import androidx.core.content.ContextCompat
 import androidx.core.text.HtmlCompat
 import androidx.fragment.app.activityViewModels
-import androidx.lifecycle.Observer
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.geeksville.android.Logging
@@ -19,9 +18,11 @@ import com.geeksville.mesh.databinding.AdapterNodeLayoutBinding
 import com.geeksville.mesh.databinding.NodelistFragmentBinding
 import com.geeksville.mesh.model.UIViewModel
 import com.geeksville.util.formatAgo
+import dagger.hilt.android.AndroidEntryPoint
 import java.net.URLEncoder
 import kotlin.math.roundToInt
 
+@AndroidEntryPoint
 class UsersFragment : ScreenFragment("Users"), Logging {
 
     private var _binding: NodelistFragmentBinding? = null

build.gradle

@@ -3,6 +3,7 @@
 buildscript {
     ext.kotlin_version = '1.6.10'
     ext.coroutines_version = "1.5.2"
+    ext.hilt_version = '2.40.5'
 
     repositories {
         google()
@@ -30,6 +31,8 @@ buildscript {
 
         // for unit testing https://github.com/bjoernQ/unmock-plugin
         classpath 'com.github.bjoernq:unmockplugin:0.7.9'
+
+        classpath "com.google.dagger:hilt-android-gradle-plugin:$hilt_version"
     }
 }