diff --git a/app/src/main/java/org/mercury_im/messenger/android/ui/base/SingleLiveEvent.java b/app/src/main/java/org/mercury_im/messenger/android/ui/base/SingleLiveEvent.java new file mode 100644 index 0000000..879bdf4 --- /dev/null +++ b/app/src/main/java/org/mercury_im/messenger/android/ui/base/SingleLiveEvent.java @@ -0,0 +1,75 @@ +/* + * Copyright 2017 Google Inc. + * + * 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 org.mercury_im.messenger.android.ui.base; + +import android.util.Log; + +import androidx.annotation.MainThread; +import androidx.annotation.NonNull; +import androidx.lifecycle.LifecycleOwner; +import androidx.lifecycle.MutableLiveData; +import androidx.lifecycle.Observer; + +import java.util.concurrent.atomic.AtomicBoolean; + +/** + * A lifecycle-aware observable that sends only new updates after subscription, used for events like + * navigation and Snackbar messages. + *
+ * This avoids a common problem with events: on configuration change (like rotation) an update + * can be emitted if the observer is active. This LiveData only calls the observable if there's an + * explicit call to setValue() or call(). + *
+ * Note that only one observer is going to be notified of changes.
+ */
+public class SingleLiveEvent