Remove divider lines from all PreferenceFragments.

(this is partially revert of ag/I0ce486f7ac6)

- Only draw divider lines on top of PreferenceCategory and
  FooterPreference

Bug: 33601143
Test: make RunSettingsRoboTests
Change-Id: I26146dcae1603dc807e54ea431910685107be94c

src/com/android/settings/core/InstrumentedPreferenceFragment.java

@@ -17,13 +17,20 @@
 package com.android.settings.core;
 
 import android.content.Context;
+import android.graphics.Color;
+import android.graphics.drawable.ColorDrawable;
+import android.graphics.drawable.Drawable;
 import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
 
 import com.android.settings.core.instrumentation.Instrumentable;
 import com.android.settings.core.instrumentation.MetricsFeatureProvider;
 import com.android.settings.core.instrumentation.VisibilityLoggerMixin;
 import com.android.settings.core.lifecycle.ObservablePreferenceFragment;
 import com.android.settings.overlay.FeatureFactory;
+import com.android.settings.widget.PreferenceDividerDecoration;
 
 /**
  * Instrumented fragment that logs visibility state.
@@ -48,6 +55,9 @@ public abstract class InstrumentedPreferenceFragment extends ObservablePreferenc
     protected final int GESTURE_DOUBLE_TAP_SCREEN = PLACEHOLDER_METRIC + 11;
     protected final int GESTURE_DOUBLE_TWIST = PLACEHOLDER_METRIC + 12;
 
+    private final PreferenceDividerDecoration mDividerDecoration =
+            new PreferenceDividerDecoration();
+
     public InstrumentedPreferenceFragment() {
         // Mixin that logs visibility change for activity.
         getLifecycle().addObserver(new VisibilityLoggerMixin(getMetricsCategory()));
@@ -59,7 +69,21 @@ public abstract class InstrumentedPreferenceFragment extends ObservablePreferenc
         mMetricsFeatureProvider = FeatureFactory.getFactory(context).getMetricsFeatureProvider();
     }
 
+    @Override
+    public View onCreateView(LayoutInflater inflater, ViewGroup container,
+            Bundle savedInstanceState) {
+        final View view = super.onCreateView(inflater, container, savedInstanceState);
+        getListView().addItemDecoration(mDividerDecoration);
+        return view;
+    }
+
     @Override
     public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
     }
+
+    @Override
+    public void setDivider(Drawable divider) {
+        mDividerDecoration.setDivider(divider);
+        super.setDivider(new ColorDrawable(Color.TRANSPARENT));
+    }
 }

src/com/android/settings/dashboard/DashboardFragment.java

@@ -17,9 +17,6 @@ package com.android.settings.dashboard;
 
 import android.app.Activity;
 import android.content.Context;
-import android.graphics.Color;
-import android.graphics.drawable.ColorDrawable;
-import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.support.annotation.VisibleForTesting;
 import android.support.v7.preference.Preference;
@@ -117,16 +114,6 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
         refreshAllPreferences(getLogTag());
     }
 
-    @Override
-    public void setDivider(Drawable divider) {
-        if (mDashboardFeatureProvider.isEnabled()) {
-            // Intercept divider and set it transparent so system divider decoration is disabled.
-            super.setDivider(new ColorDrawable(Color.TRANSPARENT));
-        } else {
-            super.setDivider(divider);
-        }
-    }
-
     @Override
     public void onStart() {
         super.onStart();

src/com/android/settings/widget/PreferenceDividerDecoration.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2016 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.widget;
+
+import android.graphics.Canvas;
+import android.graphics.drawable.Drawable;
+import android.support.v4.view.ViewCompat;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceCategory;
+import android.support.v7.preference.PreferenceGroupAdapter;
+import android.support.v7.widget.RecyclerView;
+import android.view.View;
+
+public class PreferenceDividerDecoration extends RecyclerView.ItemDecoration {
+
+    private Drawable mDivider;
+    private int mDividerHeight;
+
+    public void setDivider(Drawable divider) {
+        if (divider != null) {
+            mDividerHeight = divider.getIntrinsicHeight();
+        } else {
+            mDividerHeight = 0;
+        }
+        mDivider = divider;
+    }
+
+    public void setDividerHeight(int dividerHeight) {
+        mDividerHeight = dividerHeight;
+    }
+
+    @Override
+    public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
+        if (mDivider == null) {
+            return;
+        }
+        final int childCount = parent.getChildCount();
+        final int width = parent.getWidth();
+        for (int childViewIndex = 0; childViewIndex < childCount; childViewIndex++) {
+            final View view = parent.getChildAt(childViewIndex);
+            if (shouldDrawDividerAbove(view, parent)) {
+                int top = (int) ViewCompat.getY(view);
+                mDivider.setBounds(0, top, width, top + mDividerHeight);
+                mDivider.draw(c);
+            }
+        }
+    }
+
+    private boolean shouldDrawDividerAbove(View view, RecyclerView parent) {
+        final RecyclerView.Adapter adapter = parent.getAdapter();
+        if (adapter == null || !(adapter instanceof PreferenceGroupAdapter)) {
+            return false;
+        }
+        final PreferenceGroupAdapter prefAdapter = (PreferenceGroupAdapter) adapter;
+        final int adapterPosition = parent.getChildAdapterPosition(view);
+        if (adapterPosition == RecyclerView.NO_POSITION) {
+            return false;
+        }
+        final Preference pref = prefAdapter.getItem(adapterPosition);
+        if (pref instanceof PreferenceCategory) {
+            return adapterPosition != 0;
+        }
+        return pref instanceof FooterPreference;
+    }
+}

tests/robotests/src/com/android/settings/widget/PreferenceDividerDecorationTest.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2016 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.widget;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.drawable.Drawable;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceCategory;
+import android.support.v7.preference.PreferenceGroupAdapter;
+import android.support.v7.widget.RecyclerView;
+import android.view.View;
+
+import com.android.settings.SettingsRobolectricTestRunner;
+import com.android.settings.TestConfig;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Answers;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.annotation.Config;
+
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.anyInt;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+@RunWith(SettingsRobolectricTestRunner.class)
+@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
+public class PreferenceDividerDecorationTest {
+
+    @Mock(answer = Answers.RETURNS_DEEP_STUBS)
+    private Context mContext;
+    @Mock
+    private Drawable mDrawable;
+    @Mock
+    private Canvas mCanvas;
+    @Mock(answer = Answers.RETURNS_DEEP_STUBS)
+    private RecyclerView mRecyclerView;
+    @Mock
+    private PreferenceGroupAdapter mAdapter;
+    @Mock
+    private PreferenceCategory mPrefCategory;
+    @Mock
+    private Preference mNormalPref;
+    @Mock
+    private FooterPreference mFooterPref;
+    private PreferenceDividerDecoration mDecoration;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mDecoration = new PreferenceDividerDecoration();
+        mDecoration.setDivider(mDrawable);
+        mDecoration.setDividerHeight(3);
+    }
+
+    @Test
+    public void drawOver_footerPreference_shouldDrawDivider() {
+        when(mRecyclerView.getAdapter()).thenReturn(mAdapter);
+        when(mRecyclerView.getChildCount()).thenReturn(1);
+        when(mAdapter.getItem(anyInt())).thenReturn(mFooterPref);
+
+        mDecoration.onDrawOver(mCanvas, mRecyclerView, null /* state */);
+
+        verify(mDrawable).draw(mCanvas);
+    }
+
+    @Test
+    public void drawOver_preferenceCategory_shouldSkipFirst() {
+        when(mRecyclerView.getAdapter()).thenReturn(mAdapter);
+        when(mRecyclerView.getChildCount()).thenReturn(3);
+        when(mAdapter.getItem(anyInt())).thenReturn(mPrefCategory);
+        when(mRecyclerView.getChildAdapterPosition(any(View.class)))
+                .thenReturn(0)
+                .thenReturn(1)
+                .thenReturn(2);
+
+        mDecoration.onDrawOver(mCanvas, mRecyclerView, null /* state */);
+
+        // 3 prefCategory, should skip first draw
+        verify(mDrawable, times(2)).draw(mCanvas);
+    }
+
+    @Test
+    public void drawOver_preference_doNotDrawDivider() {
+        when(mRecyclerView.getAdapter()).thenReturn(mAdapter);
+        when(mRecyclerView.getChildCount()).thenReturn(1);
+        when(mAdapter.getItem(anyInt())).thenReturn(mNormalPref);
+
+        mDecoration.onDrawOver(mCanvas, mRecyclerView, null /* state */);
+
+        verify(mDrawable, never()).draw(mCanvas);
+    }
+}