Adds data layer for location background sample.

LocationUpdatesBackgroundKotlin/app/src/main/java/com/google/android/gms/location/sample/locationupdatesbackgroundkotlin/Utils.kt

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+/*
+ * Copyright (C) 2020 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.gms.location.sample.locationupdatesbackgroundkotlin
+
+import android.Manifest
+import android.content.Context
+import android.content.pm.PackageManager
+import androidx.core.app.ActivityCompat
+import androidx.fragment.app.Fragment
+import com.google.android.material.snackbar.Snackbar
+
+/**
+ * Helper functions to simplify permission checks/requests.
+ */
+fun Context.hasPermission(permission: String): Boolean {
+
+    // Background permissions didn't exit prior to Q, so it's approved by default.
+    if (permission == Manifest.permission.ACCESS_BACKGROUND_LOCATION &&
+        android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.Q) {
+        return true
+    }
+
+    return ActivityCompat.checkSelfPermission(this, permission) ==
+            PackageManager.PERMISSION_GRANTED
+}
+
+/**
+ * Requests permission and if the user denied a previous request, but didn't check
+ * "Don't ask again", we provide additional rationale.
+ *
+ * Note: The Snackbar should have an action to request the permission.
+ */
+fun Fragment.requestPermissionWithRationale(
+    permission: String,
+    requestCode: Int,
+    snackbar: Snackbar
+) {
+    val provideRationale = shouldShowRequestPermissionRationale(permission)
+
+    if (provideRationale) {
+        snackbar.show()
+    } else {
+        requestPermissions(arrayOf(permission), requestCode)
+    }
+}

LocationUpdatesBackgroundKotlin/app/src/main/java/com/google/android/gms/location/sample/locationupdatesbackgroundkotlin/data/LocationRepository.kt

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+/*
+ * Copyright (C) 2020 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.gms.location.sample.locationupdatesbackgroundkotlin.data
+
+import android.content.Context
+import androidx.annotation.MainThread
+import androidx.lifecycle.LiveData
+import com.google.android.gms.location.sample.locationupdatesbackgroundkotlin.data.db.MyLocationDatabase
+import com.google.android.gms.location.sample.locationupdatesbackgroundkotlin.data.db.MyLocationEntity
+import java.util.UUID
+import java.util.concurrent.ExecutorService
+import java.util.concurrent.Executors
+
+private const val TAG = "LocationRepository"
+
+/**
+ * Access point for database (MyLocation data) and location APIs (start/stop location tracking and
+ * checking tracking status).
+ */
+class LocationRepository private constructor(
+    private val myLocationDatabase: MyLocationDatabase,
+    private val myLocationManager: MyLocationManager,
+    private val executor:ExecutorService
+) {
+
+    // Database related fields/methods:
+    private val locationDao = myLocationDatabase.locationDao()
+
+    /**
+     * Returns all recorded locations from database.
+     */
+    fun getLocations(): LiveData<List<MyLocationEntity>> = locationDao.getLocations()
+
+    // Not being used now but could in future versions.
+    /**
+     * Returns specific location in database.
+     */
+    fun getLocation(id: UUID): LiveData<MyLocationEntity> = locationDao.getLocation(id)
+
+    // Not being used now but could in future versions.
+    /**
+     * Updates location in database.
+     */
+    fun updateLocation(myLocationEntity: MyLocationEntity) {
+        executor.execute {
+            locationDao.updateLocation(myLocationEntity)
+        }
+    }
+
+    /**
+     * Adds location to the database.
+     */
+    fun addLocation(myLocationEntity: MyLocationEntity) {
+        executor.execute {
+            locationDao.addLocation(myLocationEntity)
+        }
+    }
+
+    // Location related fields/methods:
+    /**
+     * Tracks whether the app is actively subscribed to location changes.
+     */
+    val trackingLocation: LiveData<Boolean> = myLocationManager.trackingLocation
+
+    /**
+     * Subscribes to location updates.
+     */
+    @MainThread
+    fun startLocationUpdates() = myLocationManager.startLocationUpdates()
+
+    /**
+     * Un-subscribes from location updates.
+     */
+    @MainThread
+    fun stopLocationUpdates() = myLocationManager.stopLocationUpdates()
+
+    companion object {
+        @Volatile private var INSTANCE: LocationRepository? = null
+
+        fun getInstance(context: Context, executor: ExecutorService): LocationRepository {
+            return INSTANCE ?: synchronized(this) {
+                INSTANCE ?: LocationRepository(
+                    MyLocationDatabase.getInstance(context),
+                    MyLocationManager.getInstance(context),
+                    executor)
+                    .also { INSTANCE = it }
+            }
+        }
+    }
+}

LocationUpdatesBackgroundKotlin/app/src/main/java/com/google/android/gms/location/sample/locationupdatesbackgroundkotlin/data/MyLocationManager.kt

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+/*
+ * Copyright (C) 2020 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.gms.location.sample.locationupdatesbackgroundkotlin.data
+
+import android.Manifest
+import android.app.PendingIntent
+import android.content.Context
+import android.content.Intent
+import android.util.Log
+import androidx.annotation.MainThread
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
+import com.google.android.gms.location.FusedLocationProviderClient
+import com.google.android.gms.location.LocationRequest
+import com.google.android.gms.location.LocationServices
+import com.google.android.gms.location.sample.locationupdatesbackgroundkotlin.LocationUpdatesBroadcastReceiver
+import com.google.android.gms.location.sample.locationupdatesbackgroundkotlin.hasPermission
+import java.util.concurrent.TimeUnit
+
+private const val TAG = "MyLocationManager"
+
+/**
+ * Manages all location related tasks for the app.
+ */
+class MyLocationManager private constructor(private val context: Context) {
+
+    private val _trackingLocation: MutableLiveData<Boolean> = MutableLiveData<Boolean>(false)
+
+    /**
+     * Tracks whether the app is actively subscribed to location changes.
+     */
+    val trackingLocation: LiveData<Boolean>
+        get() = _trackingLocation
+
+    // The Fused Location Provider provides access to location tracking APIs.
+    private val fusedLocationClient: FusedLocationProviderClient =
+        LocationServices.getFusedLocationProviderClient(context)
+
+    // Stores parameters for requests to the FusedLocationProviderApi.
+    private val locationRequest: LocationRequest = LocationRequest().apply {
+        // Sets the desired interval for active location updates. This interval is inexact. You
+        // may not receive updates at all if no location sources are available, or you may
+        // receive them slower than requested. You may also receive updates faster than
+        // requested if other applications are requesting location at a faster interval.
+        //
+        // IMPORTANT NOTE: Apps running on "O" devices (regardless of targetSdkVersion) may
+        // receive updates less frequently than this interval when the app is no longer in the
+        // foreground.
+        interval = TimeUnit.SECONDS.toMillis(60)
+
+        // Sets the fastest rate for active location updates. This interval is exact, and your
+        // application will never receive updates faster than this value.
+        fastestInterval = TimeUnit.SECONDS.toMillis(30)
+
+        // Sets the maximum time when batched location updates are delivered. Updates may be
+        // delivered sooner than this interval.
+        maxWaitTime = TimeUnit.MINUTES.toMillis(2)
+
+        priority = LocationRequest.PRIORITY_HIGH_ACCURACY
+    }
+
+    /**
+     * Creates default PendingIntent for location changes.
+     *
+     * Note: We use a BroadcastReceiver because on API level 26 and above (Oreo+), Android places
+     * limits on Services.
+     */
+    private val locationUpdatePendingIntent: PendingIntent by lazy {
+        val intent = Intent(context, LocationUpdatesBroadcastReceiver::class.java)
+        intent.action = LocationUpdatesBroadcastReceiver.ACTION_PROCESS_UPDATES
+        PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT)
+    }
+
+    /**
+     * Uses the FusedLocationProvider to start tracking location if the correct fine locations are
+     * approved.
+     *
+     * @throws SecurityException if ACCESS_FINE_LOCATION permission is removed before the
+     * FusedLocationClient's requestLocationUpdates() has been completed.
+     */
+    @Throws(SecurityException::class)
+    @MainThread
+    fun startLocationUpdates() {
+        Log.d(TAG, "startLocationUpdates()")
+
+        if (!context.hasPermission(Manifest.permission.ACCESS_FINE_LOCATION)) return
+
+        try {
+            _trackingLocation.value = true
+            // If the PendingIntent is the same as the last request (which it always is), this
+            // request will replace any requestLocationUpdates() called before.
+            fusedLocationClient.requestLocationUpdates(locationRequest, locationUpdatePendingIntent)
+        } catch (permissionRevoked: SecurityException) {
+            _trackingLocation.value = false
+
+            // Exception only occurs if the user revokes the FINE location permission before
+            // requestLocationUpdates() is finished executing (very rare).
+            Log.d(TAG, "Location permission revoked; details: $permissionRevoked")
+            throw permissionRevoked
+        }
+    }
+
+    @MainThread
+    fun stopLocationUpdates() {
+        Log.d(TAG, "stopLocationUpdates()")
+        _trackingLocation.value = false
+        fusedLocationClient.removeLocationUpdates(locationUpdatePendingIntent)
+    }
+
+    companion object {
+        @Volatile private var INSTANCE: MyLocationManager? = null
+
+        fun getInstance(context: Context): MyLocationManager {
+            return INSTANCE ?: synchronized(this) {
+                INSTANCE ?: MyLocationManager(context).also { INSTANCE = it }
+            }
+        }
+    }
+}

LocationUpdatesBackgroundKotlin/app/src/main/java/com/google/android/gms/location/sample/locationupdatesbackgroundkotlin/data/db/MyLocationDao.kt

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+/*
+ * Copyright (C) 2020 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.gms.location.sample.locationupdatesbackgroundkotlin.data.db
+
+import androidx.lifecycle.LiveData
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.Query
+import androidx.room.Update
+import java.util.UUID
+
+/**
+ * Defines database operations.
+ */
+@Dao
+interface MyLocationDao {
+
+    @Query("SELECT * FROM my_location_table ORDER BY date DESC")
+    fun getLocations(): LiveData<List<MyLocationEntity>>
+
+    @Query("SELECT * FROM my_location_table WHERE id=(:id)")
+    fun getLocation(id: UUID): LiveData<MyLocationEntity>
+
+    @Update
+    fun updateLocation(myLocationEntity: MyLocationEntity)
+
+    @Insert
+    fun addLocation(myLocationEntity: MyLocationEntity)
+}

LocationUpdatesBackgroundKotlin/app/src/main/java/com/google/android/gms/location/sample/locationupdatesbackgroundkotlin/data/db/MyLocationDatabase.kt

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+/*
+ * Copyright (C) 2020 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.gms.location.sample.locationupdatesbackgroundkotlin.data.db
+
+import android.content.Context
+import androidx.room.Database
+import androidx.room.Room
+import androidx.room.RoomDatabase
+import androidx.room.TypeConverters
+
+private const val DATABASE_NAME = "my-location-database"
+
+/**
+ * Database for storing all location data.
+ */
+@Database(entities = [MyLocationEntity::class], version = 1)
+@TypeConverters(MyLocationTypeConverters::class)
+abstract class MyLocationDatabase : RoomDatabase() {
+    abstract fun locationDao(): MyLocationDao
+
+    companion object {
+        // For Singleton instantiation
+        @Volatile private var INSTANCE: MyLocationDatabase? = null
+
+        fun getInstance(context: Context): MyLocationDatabase {
+            return INSTANCE ?: synchronized(this) {
+                INSTANCE ?: buildDatabase(context).also { INSTANCE = it }
+            }
+        }
+
+        private fun buildDatabase(context: Context): MyLocationDatabase {
+            return Room.databaseBuilder(
+                    context,
+                    MyLocationDatabase::class.java,
+                    DATABASE_NAME
+                ).build()
+        }
+    }
+}