Minor refactor

ground/src/main/java/com/google/android/ground/repository/OfflineAreaRepository.kt

@@ -25,12 +25,12 @@ import com.google.android.ground.system.GeocodingManager
 import com.google.android.ground.ui.map.Bounds
 import com.google.android.ground.ui.map.gms.mog.*
 import com.google.android.ground.ui.util.FileUtil
+import com.google.android.ground.util.deleteIfEmpty
+import com.google.android.ground.util.rangeOf
 import io.reactivex.*
 import java.io.File
 import javax.inject.Inject
 import javax.inject.Singleton
-import kotlin.math.max
-import kotlin.math.min
 import kotlinx.coroutines.flow.*
 import kotlinx.coroutines.reactive.asFlow
 import kotlinx.coroutines.reactive.awaitFirst
@@ -180,14 +180,3 @@ constructor(
     }
   }
 }
-
-private fun File?.isEmpty() = this?.listFiles().isNullOrEmpty()
-
-private fun File?.deleteIfEmpty() {
-  if (isEmpty()) this?.delete()
-}
-
-private inline fun <T> Iterable<T>.rangeOf(selector: (T) -> Int): IntRange =
-  map(selector)
-    .map { IntRange(it, it) }
-    .reduce { out, el -> IntRange(min(out.first, el.first), max(out.last, el.last)) }

ground/src/main/java/com/google/android/ground/ui/offlineareas/selector/OfflineAreaSelectorViewModel.kt

@@ -35,6 +35,8 @@ import com.google.android.ground.ui.common.SharedViewModel
 import com.google.android.ground.ui.map.Bounds
 import com.google.android.ground.ui.map.CameraPosition
 import com.google.android.ground.ui.map.MapType
+import com.google.android.ground.util.toMb
+import com.google.android.ground.util.toMbString
 import javax.inject.Inject
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.launch
@@ -139,7 +141,7 @@ internal constructor(
     }
     sizeOnDisk.postValue(offlineAreaSizeLoadingSymbol)
     visibleBottomTextViewId.postValue(R.id.size_on_disk_text_view)
-    val sizeInMb = offlineAreaRepository.estimateSizeOnDisk(bounds) / (1024f * 1024f)
+    val sizeInMb = offlineAreaRepository.estimateSizeOnDisk(bounds).toMb()
     if (sizeInMb > MAX_AREA_DOWNLOAD_SIZE_MB) {
       onLargeAreaSelected()
     } else {
@@ -153,8 +155,7 @@ internal constructor(
   }
 
   private fun onDownloadableAreaSelected(sizeInMb: Float) {
-    val sizeString = if (sizeInMb < 0.1f) "<0.1" else "%.1f".format(sizeInMb)
-    sizeOnDisk.postValue(sizeString)
+    sizeOnDisk.postValue(sizeInMb.toMbString())
     visibleBottomTextViewId.postValue(R.id.size_on_disk_text_view)
     downloadButtonEnabled.postValue(true)
   }

ground/src/main/java/com/google/android/ground/ui/offlineareas/viewer/OfflineAreaViewerViewModel.kt

@@ -31,6 +31,8 @@ import com.google.android.ground.ui.common.BaseMapViewModel
 import com.google.android.ground.ui.common.MapConfig
 import com.google.android.ground.ui.common.Navigator
 import com.google.android.ground.ui.map.MapType
+import com.google.android.ground.util.toMbString
+import com.google.android.ground.util.toMb
 import javax.inject.Inject
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.launch
@@ -68,7 +70,7 @@ constructor(
   /** Returns the offline area associated with this view model. */
   val area = MutableLiveData<OfflineArea>()
   val areaName = area.map { it.name }
-  val areaSize = MutableLiveData<Float>()
+  val areaSize = MutableLiveData<String>()
   val progressOverlayVisible = MutableLiveData<Boolean>()
 
   private var offlineAreaId: String? = null
@@ -87,7 +89,7 @@ constructor(
     viewModelScope.launch(ioDispatcher) {
       val thisArea = offlineAreaRepository.getOfflineArea(offlineAreaId!!).await()
       area.postValue(thisArea)
-      areaSize.postValue((offlineAreaRepository.sizeOnDevice(thisArea) / 1024f * 1024f))
+      areaSize.postValue((offlineAreaRepository.sizeOnDevice(thisArea).toMb().toMbString()))
     }
   }
 

ground/src/main/java/com/google/android/ground/util/FileExt.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2023 Google LLC
+ *
+ * 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
+ *
+ *     https://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.ground.util
+
+import java.io.File
+import kotlin.math.ceil
+
+typealias ByteCount = Int
+
+typealias MegabyteCount = Float
+
+/** Return true iff the file is non-null and contains other files. */
+fun File?.isEmpty() = this?.listFiles().isNullOrEmpty()
+
+/** Deletes the file if itt is non-null and doesn't contain other files. */
+fun File?.deleteIfEmpty() {
+  if (isEmpty()) this?.delete()
+}
+
+/** Returns the byte count as an equivalent megabyte count. */
+fun ByteCount.toMb(): MegabyteCount = this / 1024f * 1024f
+
+/**
+ * Returns the number of megabytes a string, replacing smaller sizes with "<1" and rounding up
+ * others.
+ */
+fun MegabyteCount.toMbString(): String = if (this < 1) "<1" else ceil(this).toString()

ground/src/main/java/com/google/android/ground/util/RangeExt.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2023 Google LLC
+ *
+ * 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
+ *
+ *     https://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.ground.util
+
+import kotlin.math.max
+import kotlin.math.min
+
+/**
+ * Returns a range containing the smallest and largest among all values produced by the selector
+ * function applied to each element in the iterable collection.
+ */
+inline fun <T> Iterable<T>.rangeOf(selector: (T) -> Int): IntRange =
+  map(selector)
+    .map { IntRange(it, it) }
+    .reduce { out, el -> IntRange(min(out.first, el.first), max(out.last, el.last)) }

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

@@ -171,5 +171,5 @@
   <string name="area">Area</string>
   <string name="unnamed_point">Unnamed point</string>
   <string name="unnamed_area">Unnamed area</string>
-  <string name="offline_area_size_on_disk_mb">%.1f\u00A0MB on disk</string>
+  <string name="offline_area_size_on_disk_mb">%s\u00A0MB on disk</string>
 </resources>