Move ActionBarShadowController to settingslib.

And remove dependency to settingslib.core.Lifecycle. This class use
androidx.Lifecycle instead.

Bug: 123311100
Test: robotests
Change-Id: I80bbbf4bc2759e574d8dabf1799b3bded216f2f3

5 files changed, 287 insertions, 0 deletions

diff --git a/packages/SettingsLib/ActionBarShadow/Android.bp b/packages/SettingsLib/ActionBarShadow/Android.bp
new file mode 100644
index 000000000000..d2848564abea
--- /dev/null
+++ b/packages/SettingsLib/ActionBarShadow/Android.bp
@@ -0,0 +1,14 @@
+android_library {
+    name: "SettingsLibActionBarShadow",
+
+    srcs: ["src/**/*.java"],
+
+    static_libs: [
+        "androidx.annotation_annotation",
+        "androidx.lifecycle_lifecycle-runtime",
+        "androidx.recyclerview_recyclerview",
+    ],
+
+    sdk_version: "system_current",
+    min_sdk_version: "21",
+}
diff --git a/packages/SettingsLib/ActionBarShadow/AndroidManifest.xml b/packages/SettingsLib/ActionBarShadow/AndroidManifest.xml
new file mode 100644
index 000000000000..4b9f1ab8d6cc
--- /dev/null
+++ b/packages/SettingsLib/ActionBarShadow/AndroidManifest.xml
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright (C) 2018 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.
+  -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="com.android.settingslib.widget">
+
+    <uses-sdk android:minSdkVersion="21" />
+
+</manifest>
diff --git a/packages/SettingsLib/ActionBarShadow/src/com/android/settingslib/widget/ActionBarShadowController.java b/packages/SettingsLib/ActionBarShadow/src/com/android/settingslib/widget/ActionBarShadowController.java
new file mode 100644
index 000000000000..68ba5fbd120f
--- /dev/null
+++ b/packages/SettingsLib/ActionBarShadow/src/com/android/settingslib/widget/ActionBarShadowController.java
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2019 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.settingslib.widget;
+
+import static androidx.lifecycle.Lifecycle.Event.ON_START;
+import static androidx.lifecycle.Lifecycle.Event.ON_STOP;
+
+import android.app.ActionBar;
+import android.app.Activity;
+import android.view.View;
+
+import androidx.annotation.VisibleForTesting;
+import androidx.lifecycle.Lifecycle;
+import androidx.lifecycle.LifecycleObserver;
+import androidx.lifecycle.OnLifecycleEvent;
+import androidx.recyclerview.widget.RecyclerView;
+
+/**
+ * UI controller that adds a shadow appear/disappear animation to action bar scroll.
+ */
+public class ActionBarShadowController implements LifecycleObserver {
+
+    @VisibleForTesting
+    static final float ELEVATION_HIGH = 8;
+    @VisibleForTesting
+    static final float ELEVATION_LOW = 0;
+
+    @VisibleForTesting
+    ScrollChangeWatcher mScrollChangeWatcher;
+    private RecyclerView mRecyclerView;
+    private boolean mIsScrollWatcherAttached;
+
+    /**
+     * Wire up the animation to to an {@link Activity}. Shadow will be applied to activity's
+     * action bar.
+     */
+    public static ActionBarShadowController attachToRecyclerView(
+            Activity activity, Lifecycle lifecycle, RecyclerView recyclerView) {
+        return new ActionBarShadowController(activity, lifecycle, recyclerView);
+    }
+
+    /**
+     * Wire up the animation to to a {@link View}. Shadow will be applied to the view.
+     */
+    public static ActionBarShadowController attachToRecyclerView(
+            View anchorView, Lifecycle lifecycle, RecyclerView recyclerView) {
+        return new ActionBarShadowController(anchorView, lifecycle, recyclerView);
+    }
+
+    private ActionBarShadowController(Activity activity, Lifecycle lifecycle,
+            RecyclerView recyclerView) {
+        mScrollChangeWatcher =
+                new ActionBarShadowController.ScrollChangeWatcher(activity);
+        mRecyclerView = recyclerView;
+        attachScrollWatcher();
+        lifecycle.addObserver(this);
+    }
+
+    private ActionBarShadowController(View anchorView, Lifecycle lifecycle,
+            RecyclerView recyclerView) {
+        mScrollChangeWatcher =
+                new ActionBarShadowController.ScrollChangeWatcher(anchorView);
+        mRecyclerView = recyclerView;
+        attachScrollWatcher();
+        lifecycle.addObserver(this);
+    }
+
+    @OnLifecycleEvent(ON_START)
+    private void attachScrollWatcher() {
+        if (!mIsScrollWatcherAttached) {
+            mIsScrollWatcherAttached = true;
+            mRecyclerView.addOnScrollListener(mScrollChangeWatcher);
+            mScrollChangeWatcher.updateDropShadow(mRecyclerView);
+        }
+    }
+
+    @OnLifecycleEvent(ON_STOP)
+    private void detachScrollWatcher() {
+        mRecyclerView.removeOnScrollListener(mScrollChangeWatcher);
+        mIsScrollWatcherAttached = false;
+    }
+
+    /**
+     * Update the drop shadow as the scrollable entity is scrolled.
+     */
+    final class ScrollChangeWatcher extends RecyclerView.OnScrollListener {
+
+        private final Activity mActivity;
+        private final View mAnchorView;
+
+        ScrollChangeWatcher(Activity activity) {
+            mActivity = activity;
+            mAnchorView = null;
+        }
+
+        ScrollChangeWatcher(View anchorView) {
+            mAnchorView = anchorView;
+            mActivity = null;
+        }
+
+        // RecyclerView scrolled.
+        @Override
+        public void onScrolled(RecyclerView view, int dx, int dy) {
+            updateDropShadow(view);
+        }
+
+        public void updateDropShadow(View view) {
+            final boolean shouldShowShadow = view.canScrollVertically(-1);
+            if (mAnchorView != null) {
+                mAnchorView.setElevation(shouldShowShadow ? ELEVATION_HIGH : ELEVATION_LOW);
+            } else if (mActivity != null) { // activity can become null when running monkey
+                final ActionBar actionBar = mActivity.getActionBar();
+                if (actionBar != null) {
+                    actionBar.setElevation(shouldShowShadow ? ELEVATION_HIGH : ELEVATION_LOW);
+                }
+            }
+        }
+    }
+}
diff --git a/packages/SettingsLib/Android.bp b/packages/SettingsLib/Android.bp
index 2321790fa960..5a81f8bc6566 100644
--- a/packages/SettingsLib/Android.bp
+++ b/packages/SettingsLib/Android.bp
@@ -13,6 +13,7 @@ android_library {
 
         "SettingsLibHelpUtils",
         "SettingsLibRestrictedLockUtils",
+        "SettingsLibActionBarShadow",
         "SettingsLibAppPreference",
         "SettingsLibSearchWidget",
         "SettingsLibSettingsSpinner",
diff --git a/packages/SettingsLib/tests/robotests/src/com/android/settingslib/widget/ActionBarShadowControllerTest.java b/packages/SettingsLib/tests/robotests/src/com/android/settingslib/widget/ActionBarShadowControllerTest.java
new file mode 100644
index 000000000000..a25b51298d3e
--- /dev/null
+++ b/packages/SettingsLib/tests/robotests/src/com/android/settingslib/widget/ActionBarShadowControllerTest.java
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2019 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.settingslib.widget;
+
+import static androidx.lifecycle.Lifecycle.Event.ON_START;
+import static androidx.lifecycle.Lifecycle.Event.ON_STOP;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.app.ActionBar;
+import android.app.Activity;
+import android.view.View;
+
+import androidx.lifecycle.LifecycleOwner;
+import androidx.recyclerview.widget.RecyclerView;
+
+import com.android.settingslib.core.lifecycle.Lifecycle;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+@RunWith(RobolectricTestRunner.class)
+public class ActionBarShadowControllerTest {
+
+    @Mock
+    private RecyclerView mRecyclerView;
+    @Mock
+    private Activity mActivity;
+    @Mock
+    private ActionBar mActionBar;
+    private Lifecycle mLifecycle;
+    private LifecycleOwner mLifecycleOwner;
+    private View mView;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        when(mActivity.getActionBar()).thenReturn(mActionBar);
+        mView = new View(RuntimeEnvironment.application);
+        mLifecycleOwner = () -> mLifecycle;
+        mLifecycle = new Lifecycle(mLifecycleOwner);
+    }
+
+    @Test
+    public void attachToRecyclerView_shouldAddScrollWatcherAndUpdateActionBar() {
+        when(mRecyclerView.canScrollVertically(-1)).thenReturn(false);
+
+        ActionBarShadowController.attachToRecyclerView(mActivity, mLifecycle, mRecyclerView);
+
+        verify(mActionBar).setElevation(ActionBarShadowController.ELEVATION_LOW);
+    }
+
+    @Test
+    public void attachToRecyclerView_customViewAsActionBar_shouldUpdateElevationOnScroll() {
+        // Setup
+        mView.setElevation(50);
+        when(mRecyclerView.canScrollVertically(-1)).thenReturn(false);
+        final ActionBarShadowController controller =
+                ActionBarShadowController.attachToRecyclerView(mView, mLifecycle, mRecyclerView);
+        assertThat(mView.getElevation()).isEqualTo(ActionBarShadowController.ELEVATION_LOW);
+
+        // Scroll
+        when(mRecyclerView.canScrollVertically(-1)).thenReturn(true);
+        controller.mScrollChangeWatcher.onScrolled(mRecyclerView, 10 /* dx */, 10 /* dy */);
+        assertThat(mView.getElevation()).isEqualTo(ActionBarShadowController.ELEVATION_HIGH);
+    }
+
+    @Test
+    public void attachToRecyclerView_lifecycleChange_shouldAttachDetach() {
+        ActionBarShadowController.attachToRecyclerView(mActivity, mLifecycle, mRecyclerView);
+
+        verify(mRecyclerView).addOnScrollListener(any());
+
+        mLifecycle.handleLifecycleEvent(ON_START);
+        mLifecycle.handleLifecycleEvent(ON_STOP);
+        verify(mRecyclerView).removeOnScrollListener(any());
+
+        mLifecycle.handleLifecycleEvent(ON_START);
+        verify(mRecyclerView, times(2)).addOnScrollListener(any());
+    }
+
+    @Test
+    public void onScrolled_nullAnchorViewAndActivity_shouldNotCrash() {
+        final Activity activity = null;
+        final ActionBarShadowController controller =
+                ActionBarShadowController.attachToRecyclerView(activity, mLifecycle, mRecyclerView);
+
+        // Scroll
+        controller.mScrollChangeWatcher.onScrolled(mRecyclerView, 10 /* dx */, 10 /* dy */);
+        // no crash
+    }
+}