1 files changed, 47 insertions, 0 deletions
diff --git a/src/com/android/car/messenger/impl/datamodels/RefreshLiveData.java b/src/com/android/car/messenger/impl/datamodels/RefreshLiveData.java
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+++ b/src/com/android/car/messenger/impl/datamodels/RefreshLiveData.java
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+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * 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.android.car.messenger.impl.datamodels;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.lifecycle.LiveData;
+
+/**
+ * Refresh live data for other live data to force refresh. When a live data listens for updates, it
+ * can refresh its data and repost as needed. This typically occurs when the user revisits the
+ * activity from the background. The background has a number of states that leads to live datas not
+ * being updated. The content observer from the telephony database does not always update when in
+ * the background if something changes. Same thing occurs with shared preferences. By checking the
+ * data again for any stale data when we resume, we can ensure the latest data is provided.
+ */
+public class RefreshLiveData extends LiveData<Boolean> {
+
+    @Nullable private static RefreshLiveData sInstance;
+
+    /** Gets the instance of {@link RefreshLiveData} */
+    @NonNull
+    public static RefreshLiveData getInstance() {
+        if (sInstance == null) {
+            sInstance = new RefreshLiveData();
+        }
+        return sInstance;
+    }
+
+    /** Posts value to listeners to refresh */
+    public void refresh() {
+        postValue(true);
+    }
+}