Improve Stability of Calendar Widget on Android (#238)

android/app/build.gradle

@@ -89,7 +89,7 @@ flutter {
 
 dependencies {
     implementation 'com.android.support:multidex'
-    implementation 'joda-time:joda-time:2.12.6'
+    implementation 'joda-time:joda-time:2.12.7'
     def appcompat_version = "1.6.1"
     implementation("androidx.appcompat:appcompat:$appcompat_version")
     implementation("androidx.appcompat:appcompat-resources:$appcompat_version")

android/app/proguard-rules.pro

@@ -1,4 +1,42 @@
+# joda
 -keep class org.joda.** {*;}
 -dontwarn org.joda.**
+
+# prettytime
+-keep class org.ocpsoft.pretty.time.i18n.**
 -keep class org.ocpsoft.prettytime.i18n.**
+-keep class org.ocpsoft.prettytime.units.**
 -keepnames class ** implements org.ocpsoft.prettytime.TimeUnit
+
+# gson
+-keepclassmembers,allowobfuscation class * {
+  @com.google.gson.annotations.SerializedName <fields>;
+}
+-keep class * {
+  @com.google.gson.annotations.SerializedName <fields>;
+}
+-if class *
+-keepclasseswithmembers class <1> {
+    <init>(...);
+    @com.google.gson.annotations.SerializedName <fields>;
+}
+-keepnames class com.fasterxml.jackson.databind.** { *; }
+-dontwarn com.fasterxml.jackson.databind.**
+
+# entires recommended by Android Studio
+-dontwarn com.google.android.play.core.splitcompat.SplitCompatApplication
+-dontwarn com.google.android.play.core.splitinstall.SplitInstallManager
+-dontwarn com.google.android.play.core.splitinstall.SplitInstallRequest$Builder
+-dontwarn com.google.android.play.core.splitinstall.SplitInstallRequest
+-dontwarn com.google.android.play.core.splitinstall.SplitInstallStateUpdatedListener
+-dontwarn com.google.android.play.core.tasks.OnFailureListener
+-dontwarn com.google.android.play.core.tasks.OnSuccessListener
+-dontwarn com.google.android.play.core.tasks.Task
+-dontwarn com.google.api.client.http.GenericUrl
+-dontwarn com.google.api.client.http.HttpHeaders
+-dontwarn com.google.api.client.http.HttpRequest
+-dontwarn com.google.api.client.http.HttpRequestFactory
+-dontwarn com.google.api.client.http.HttpResponse
+-dontwarn com.google.api.client.http.HttpTransport
+-dontwarn com.google.api.client.http.javanet.NetHttpTransport$Builder
+-dontwarn com.google.api.client.http.javanet.NetHttpTransport

android/app/src/main/kotlin/de/tum/in/tumcampus/util/DateTimeSerializer.kt

@@ -7,17 +7,21 @@ import org.joda.time.DateTime
 import org.joda.time.format.DateTimeFormat
 import java.lang.reflect.Type
 
-class LocalDateTimeDeserializer : JsonDeserializer<DateTime> {
+class LocalDateTimeDeserializer : JsonDeserializer<DateTime?> {
     override fun deserialize(
             json: JsonElement?,
             typeOfT: Type?,
             context: JsonDeserializationContext?
-    ): DateTime {
+    ): DateTime? {
         return deserializeStringToDate(json?.asString)
     }
 }
 
-fun deserializeStringToDate(dateString: String?): DateTime {
-    val formatter = DateTimeFormat.forPattern("yyyy-MM-dd'T'HH:mm:ss.SSSSSS")
-    return DateTime.parse(dateString, formatter)
+fun deserializeStringToDate(dateString: String?): DateTime? {
+    return try {
+        val formatter = DateTimeFormat.forPattern("yyyy-MM-dd'T'HH:mm:ss.SSSSSS")
+        DateTime.parse(dateString, formatter)
+    } catch (_: Exception) {
+        null
+    }
 }

android/app/src/main/kotlin/de/tum/in/tumcampus/widgets/calendar/CalendarWidget.kt

@@ -51,8 +51,8 @@ private fun updateAppWidget(
     val p = PrettyTime()
     val widgetData = HomeWidgetPlugin.getData(context)
     val lastSaved = widgetData.getString("calendar_save", null)
-    val lastSavedDate = deserializeStringToDate(lastSaved).toLocalDate()
-    val lastSavedDateString = p.format( deserializeStringToDate(lastSaved).toDate())
+    val lastSavedDate = deserializeStringToDate(lastSaved)?.toLocalDate()
+    val lastSavedDateString = p.format( deserializeStringToDate(lastSaved)?.toDate())
     remoteViews.setTextViewText(R.id.calendar_widget_updated_on, lastSavedDateString)
 
     val pendingIntentWithData = HomeWidgetLaunchIntent.getActivity(

lib/base/networking/cache/cache.dart

@@ -9,21 +9,7 @@ class Cache {
 
   Cache({required this.isar});
 
-  void add(String body, Uri uri) {
-    final today = DateTime.now();
-    final cacheEntry = CacheEntry(
-      id: fastHash(uri.toString()),
-      url: uri.toString(),
-      validUntil: today.add(ttl),
-      saved: today,
-      data: body,
-    );
-    isar.writeTxn(
-      () => isar.cacheEntrys.put(cacheEntry),
-    );
-  }
-
-  void addString(String body, String uri) {
+  void add(String body, String uri) {
     final today = DateTime.now();
     final cacheEntry = CacheEntry(
       id: fastHash(uri),
@@ -37,31 +23,31 @@ class Cache {
     );
   }
 
-  CacheEntry? get(Uri uri) {
-    final hash = fastHash(uri.toString());
+  CacheEntry? get(String uri) {
+    final hash = fastHash(uri);
     final entry = isar.txnSync(() => isar.cacheEntrys.getSync(hash));
     if (entry != null) {
       final today = DateTime.now();
       if (entry.validUntil.isAfter(today)) {
         return entry;
       } else {
-        isar.writeTxnSync(() => isar.cacheEntrys.deleteSync(hash));
+        isar.writeTxn(() => isar.cacheEntrys.delete(hash));
         return null;
       }
     } else {
       return null;
     }
   }
 
-  CacheEntry? getWithString(String uri) {
+  Future<CacheEntry?> getAsync(String uri) async {
     final hash = fastHash(uri);
-    final entry = isar.txnSync(() => isar.cacheEntrys.getSync(hash));
+    final entry = await isar.txn(() => isar.cacheEntrys.get(hash));
     if (entry != null) {
       final today = DateTime.now();
       if (entry.validUntil.isAfter(today)) {
         return entry;
       } else {
-        isar.writeTxnSync(() => isar.cacheEntrys.deleteSync(hash));
+        isar.writeTxn(() => isar.cacheEntrys.delete(hash));
         return null;
       }
     } else {

lib/base/networking/cache/grpc_cache_interceptor.dart

@@ -29,7 +29,7 @@ class GrpcCacheInterceptor implements ClientInterceptor {
     ClientUnaryInvoker<Q, R> invoker,
   ) {
     final key = method.path;
-    final cachedResponse = cache.getWithString(key);
+    final cachedResponse = cache.get(key);
     final factory = _getFactory<R>();
     if (cachedResponse != null && factory != null) {
       final data = factory(cachedResponse.data);
@@ -47,7 +47,7 @@ class GrpcCacheInterceptor implements ClientInterceptor {
     /// If not found in cache, invoke the actual RPC and cache the response
     final response = invoker(method, request, options);
     response.then((data) {
-      cache.addString((data as GeneratedMessage).writeToJson(), key);
+      cache.add((data as GeneratedMessage).writeToJson(), key);
     });
 
     return response;

lib/base/networking/cache/rest_cache_interceptor.dart

@@ -29,7 +29,7 @@ class RestCacheInterceptor implements Interceptor {
       if (options.extra["forcedRefresh"] == "true") {
         cache.delete(key);
       } else {
-        final cacheEntry = cache.getWithString(key);
+        final cacheEntry = await cache.getAsync(key);
 
         /// device is online, fetch every 10 minutes
         if (cacheEntry != null &&
@@ -54,7 +54,7 @@ class RestCacheInterceptor implements Interceptor {
       if (options.extra["forcedRefresh"] == "true") {
         cache.delete(key);
       } else {
-        final cacheEntry = cache.getWithString(key);
+        final cacheEntry = await cache.getAsync(key);
         if (cacheEntry != null &&
             DateTime.now().difference(cacheEntry.saved).inDays <= 30) {
           return handler.resolve(
@@ -78,7 +78,7 @@ class RestCacheInterceptor implements Interceptor {
   @override
   void onResponse(Response response, ResponseInterceptorHandler handler) {
     final key = response.realUri.toString();
-    cache.addString(response.data, key);
+    cache.add(response.data, key);
     response.extra = response.extra..addAll({"saved": DateTime.now()});
     handler.next(response);
   }