[Settings] Code refactor for Lifecycle listening
This is an abstract class for building a set of callback behavior
based on Lifecycle status change.
Through extending this class, the implemented methods are invoked
only when required.
Bug: 229689535
Test: unit test
Change-Id: I7534393546f821738a63ebde121a5a88ee03b23b
(cherry picked from commit 9a4c66d23ba1631350bcdf5d4bba0d5067e2beff)
diff --git a/src/com/android/settings/network/helper/LifecycleCallbackAdapter.java b/src/com/android/settings/network/helper/LifecycleCallbackAdapter.java
new file mode 100644
index 0000000..548eae5
--- /dev/null
+++ b/src/com/android/settings/network/helper/LifecycleCallbackAdapter.java
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2022 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.settings.network.helper;
+
+import androidx.annotation.MainThread;
+import androidx.annotation.NonNull;
+import androidx.annotation.VisibleForTesting;
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.LifecycleEventObserver;
+import androidx.lifecycle.LifecycleOwner;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * A {@link androidx.lifecycle.LifecycleObserver} implementation of adapter over callback.
+ *
+ * Which including:
+ * 1. Request to active callback when Lifecycle.State.STARTED
+ * 2. Request to inactive callback when Lifecycle.State.STOPPED
+ * 3. Close (no further resume) when Lifecycle.State.DESTROYED
+ */
+@VisibleForTesting
+abstract class LifecycleCallbackAdapter implements LifecycleEventObserver, AutoCloseable {
+ private static final String TAG = "LifecycleCallbackAdapter";
+ private AtomicReference<Lifecycle> mLifecycle = new AtomicReference<Lifecycle>();
+
+ /**
+ * Constructor
+ * @param lifecycle {@link Lifecycle} to monitor
+ */
+ @VisibleForTesting
+ protected LifecycleCallbackAdapter(@NonNull Lifecycle lifecycle) {
+ mLifecycle.set(lifecycle);
+ lifecycle.addObserver(this);
+ }
+
+ /**
+ * Get {@link Lifecycle} under monitor.
+ * @return {@link Lifecycle}. Return {@code null} when closed.
+ */
+ @VisibleForTesting
+ public Lifecycle getLifecycle() {
+ return mLifecycle.get();
+ }
+
+ /**
+ * Check current callback status.
+ * @return true when callback is active.
+ */
+ public abstract boolean isCallbackActive();
+
+ /**
+ * Change callback status.
+ * @param isActive true to active callback, otherwise inactive.
+ */
+ public abstract void setCallbackActive(boolean isActive);
+
+ /**
+ * Implementation of LifecycleEventObserver.
+ */
+ public void onStateChanged(LifecycleOwner source, Lifecycle.Event event) {
+ if (mLifecycle.get() == null) {
+ return;
+ }
+
+ Lifecycle.State state = event.getTargetState();
+ boolean expectCallbackActive = state.isAtLeast(Lifecycle.State.STARTED);
+ if (expectCallbackActive != isCallbackActive()) {
+ setCallbackActive(expectCallbackActive);
+ }
+ if (state == Lifecycle.State.DESTROYED) {
+ close();
+ }
+ }
+
+ /**
+ * Implementation of AutoCloseable.
+ */
+ @MainThread
+ public void close() {
+ Lifecycle lifecycle = mLifecycle.getAndSet(null);
+ if (lifecycle != null) {
+ lifecycle.removeObserver(this);
+ }
+ }
+}
diff --git a/tests/unit/src/com/android/settings/network/helper/LifecycleCallbackAdapterTest.java b/tests/unit/src/com/android/settings/network/helper/LifecycleCallbackAdapterTest.java
new file mode 100644
index 0000000..ddeb3f8
--- /dev/null
+++ b/tests/unit/src/com/android/settings/network/helper/LifecycleCallbackAdapterTest.java
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2022 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.settings.network.helper;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.LifecycleOwner;
+import androidx.lifecycle.LifecycleRegistry;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+public class LifecycleCallbackAdapterTest implements LifecycleOwner {
+
+ private final LifecycleRegistry mRegistry = LifecycleRegistry.createUnsafe(this);
+
+ private TestObj mTarget;
+
+ @Before
+ public void setUp() {
+ mTarget = new TestObj(getLifecycle());
+ }
+
+ public Lifecycle getLifecycle() {
+ return mRegistry;
+ }
+
+ @Test
+ public void lifecycle_get_lifecycleToMonitor() {
+ assertThat(mTarget.getLifecycle()).isEqualTo(mRegistry);
+ }
+
+ @Test
+ public void lifecycle_stateChangeToStart_callbackActive() {
+ mRegistry.handleLifecycleEvent(Lifecycle.Event.ON_CREATE);
+
+ assertThat(mTarget.getCallbackCount()).isEqualTo(0);
+ assertThat(mTarget.isCallbackActive()).isEqualTo(Boolean.FALSE);
+
+ mRegistry.handleLifecycleEvent(Lifecycle.Event.ON_START);
+
+ assertThat(mTarget.getCallbackCount()).isEqualTo(1);
+ assertThat(mTarget.isCallbackActive()).isEqualTo(Boolean.TRUE);
+ }
+
+ @Test
+ public void lifecycle_stateChangeToStop_callbackInActive() {
+ mRegistry.handleLifecycleEvent(Lifecycle.Event.ON_CREATE);
+ mRegistry.handleLifecycleEvent(Lifecycle.Event.ON_START);
+ mRegistry.handleLifecycleEvent(Lifecycle.Event.ON_STOP);
+
+ assertThat(mTarget.getCallbackCount()).isEqualTo(2);
+ assertThat(mTarget.isCallbackActive()).isEqualTo(Boolean.FALSE);
+ }
+
+ @Test
+ public void lifecycle_stateChangeToDestroy_noFurtherActive() {
+ mRegistry.handleLifecycleEvent(Lifecycle.Event.ON_CREATE);
+ mRegistry.handleLifecycleEvent(Lifecycle.Event.ON_START);
+ mRegistry.handleLifecycleEvent(Lifecycle.Event.ON_STOP);
+ mRegistry.handleLifecycleEvent(Lifecycle.Event.ON_DESTROY);
+
+ assertThat(mTarget.getCallbackCount()).isEqualTo(2);
+ assertThat(mTarget.isCallbackActive()).isEqualTo(Boolean.FALSE);
+
+ mRegistry.handleLifecycleEvent(Lifecycle.Event.ON_CREATE);
+ mRegistry.handleLifecycleEvent(Lifecycle.Event.ON_START);
+
+ assertThat(mTarget.getCallbackCount()).isEqualTo(2);
+ assertThat(mTarget.isCallbackActive()).isEqualTo(Boolean.FALSE);
+ }
+
+ public static class TestObj extends LifecycleCallbackAdapter {
+ boolean mIsActive;
+ int mNumberOfCallback;
+
+ public TestObj(Lifecycle lifecycle) {
+ super(lifecycle);
+ }
+
+ public boolean isCallbackActive() {
+ return mIsActive;
+ }
+
+ public void setCallbackActive(boolean isActive) {
+ mIsActive = isActive;
+ mNumberOfCallback ++;
+ }
+
+ protected int getCallbackCount() {
+ return mNumberOfCallback;
+ }
+ }
+}