Error Handling for urlConnection

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

@@ -85,7 +85,7 @@
    * Downloads tiles in the specified bounds and stores them in the local filesystem. Emits the
    * number of bytes processed and total expected bytes as the download progresses.
    */
-  suspend fun downloadTiles(bounds: Bounds): Flow<Pair<Int, Int>> = flow {
+  fun downloadTiles(bounds: Bounds): Flow<Pair<Int, Int>> = flow {
     val requests = mogClient.buildTilesRequests(bounds)
     val totalBytes = requests.sumOf { it.totalBytes }
     var bytesDownloaded = 0

ground/src/main/java/com/google/android/ground/ui/map/gms/mog/UrlInputStream.kt

@@ -22,7 +22,7 @@ import java.io.InputStream
 import java.net.HttpURLConnection
 import java.net.URL
 
-const val READ_TIMEOUT_MS = 5 * 1000
+private const val READ_TIMEOUT_MS = 5 * 1000
 
 /**
  * @constructor Creates a [UrlInputStream] by opening a connection to an actual URL, requesting the

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

@@ -20,12 +20,16 @@
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import android.widget.Toast
 import androidx.compose.runtime.livedata.observeAsState
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.ui.platform.ComposeView
+import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.repeatOnLifecycle
 import androidx.navigation.fragment.findNavController
+import com.google.android.ground.R
 import com.google.android.ground.databinding.OfflineAreaSelectorFragBinding
 import com.google.android.ground.ui.common.AbstractMapContainerFragment
 import com.google.android.ground.ui.common.BaseMapViewModel
@@ -62,8 +66,17 @@
 
   override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
     super.onViewCreated(view, savedInstanceState)
-    viewModel.isDownloadProgressVisible.observe(viewLifecycleOwner) {
-      showDownloadProgressDialog(it)
+    viewLifecycleOwner.lifecycleScope.launch {
+      repeatOnLifecycle(Lifecycle.State.RESUMED) {
+        viewModel.isDownloadProgressVisible.observe(viewLifecycleOwner) {
+          showDownloadProgressDialog(it)
+        }
+        viewModel.isFailure.observe(viewLifecycleOwner) {
+          if (it) {
+            Toast.makeText(context, R.string.offline_area_download_error, Toast.LENGTH_LONG).show()
+          }
+        }
+      }
     }
 
     lifecycleScope.launch {

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

@@ -39,6 +39,7 @@
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.asSharedFlow
+import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.launch
 
 private const val MIN_DOWNLOAD_ZOOM_LEVEL = 9
@@ -77,6 +78,7 @@
   val downloadProgress = MutableLiveData(0f)
   val bottomText = MutableLiveData<String?>(null)
   val downloadButtonEnabled = MutableLiveData(false)
+  val isFailure = MutableLiveData(false)
 
   private val _navigate = MutableSharedFlow<UiState>(replay = 0)
   val navigate = _navigate.asSharedFlow()
@@ -98,20 +100,30 @@
     isDownloadProgressVisible.value = true
     downloadProgress.value = 0f
     viewModelScope.launch(ioDispatcher) {
-      offlineAreaRepository.downloadTiles(viewport!!).collect { (bytesDownloaded, totalBytes) ->
-        val progressValue =
-          if (totalBytes > 0) {
-            (bytesDownloaded.toFloat() / totalBytes.toFloat()).coerceIn(0f, 1f)
-          } else {
-            0f
-          }
-        downloadProgress.postValue(progressValue)
-      }
+      offlineAreaRepository
+        .downloadTiles(viewport!!)
+        .catch {
+          isFailure.postValue(true)
+          isDownloadProgressVisible.postValue(false)
+        }
+        .collect { (bytesDownloaded, totalBytes) ->
+          updateDownloadProgress(bytesDownloaded, totalBytes)
+        }
       isDownloadProgressVisible.postValue(false)
       _navigate.emit(UiState.OfflineAreaBackToHomeScreen)
     }
   }
 
+  private fun updateDownloadProgress(bytesDownloaded: Int, totalBytes: Int) {
+    val progressValue =
+      if (totalBytes > 0) {
+        (bytesDownloaded.toFloat() / totalBytes.toFloat()).coerceIn(0f, 1f)
+      } else {
+        0f
+      }
+    downloadProgress.postValue(progressValue)
+  }
+
   fun onCancelClick() {
     viewModelScope.launch { _navigate.emit(UiState.Up) }
   }

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

@@ -52,6 +52,7 @@
   <string name="settings">Configuración</string>
   <string name="offline_area_viewer_title">Área descargada</string>
   <string name="offline_area_viewer_remove_button">Eliminar del dispositivo</string>
+  <string name="offline_area_download_error">¡Error de descarga. Por favor inténtalo de nuevo</string>
   <!-- Label of button used enter the offline area selector. -->
   <string name="offline_area_selector_select">Seleccionar área</string>
   <string name="no_basemaps_downloaded">No se ha descargado ningún mapa para su uso sin conexión</string>

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

@@ -53,6 +53,7 @@
   <string name="settings">Paramètres</string>
   <string name="offline_area_viewer_title">Zone téléchargée</string>
   <string name="offline_area_viewer_remove_button">Supprimer de l&#8217;appareil</string>
+  <string name="offline_area_download_error">Échec du téléchargement. Veuillez réessayer</string>
   <!-- Label of button used enter the offline area selector. -->
   <string name="offline_area_selector_select">Sélectionnez une zone</string>
   <string name="no_basemaps_downloaded">Aucune image n&#8217;a été téléchargée pour l&#8217;utilisation hors ligne. Appuyez sur « Sélectionner et télécharger » pour commencer.</string>

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

@@ -52,6 +52,7 @@
   <string name="settings">Configurações</string>
   <string name="offline_area_viewer_title">Área descarregada</string>
   <string name="offline_area_viewer_remove_button">Remover do dispositivo</string>
+  <string name="offline_area_download_error">Falha no download! Por favor, tente novamente</string>
   <!-- Label of button used enter the offline area selector. -->
   <string name="offline_area_selector_select">Selecionar área</string>
   <string name="no_basemaps_downloaded">Nenhuma imagem de mapa descarregada para uso offline</string>

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

@@ -53,6 +53,7 @@
   <string name="settings">Settings</string>
   <string name="offline_area_viewer_title">Downloaded area</string>
   <string name="offline_area_viewer_remove_button">Remove from device</string>
+  <string name="offline_area_download_error">Download failed. Please try again</string>
   <!-- Label of button used enter the offline area selector. -->
   <string name="offline_area_selector_select">Select area</string>
   <string name="no_basemaps_downloaded">No map imagery downloaded for offline use</string>