Insert dynamic dashboard tiles into optional placeholders

Insteads of inserting tile onto screen using absolute priority values,
now each page can have a placeholder preference, and at run time we will
add dynamic dashboard tiles to placeholder's place.

Bug: 32827787
Test: RunSettingsRoboTests
Change-Id: I1fe9e11dce4eb6fb4a9b56af05a2b8e5cdae00d2

src/com/android/settings/SecuritySettings.java

@@ -781,8 +781,8 @@ public class SecuritySettings extends SettingsPreferenceFragment
         final List<Preference> preferences = new ArrayList<>();
         for (Tile tile : tiles) {
             final Preference pref = new Preference(getPrefContext());
-            mDashboardFeatureProvider
-                    .bindPreferenceToTile(getActivity(), pref, tile, null /* key */);
+            mDashboardFeatureProvider.bindPreferenceToTile(getActivity(), pref, tile,
+                    null /* key */, Preference.DEFAULT_ORDER/* baseOrder */);
             preferences.add(pref);
         }
         return preferences;

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

@@ -63,12 +63,16 @@ public interface DashboardFeatureProvider {
      * @param pref The preference to bind data
      * @param tile The binding data
      * @param key They key for preference. If null, we will generate one from tile data
+     * @param baseOrder The order offset value. When binding, pref's order is determined by
+     * both this value and tile's own priority.
      */
-    void bindPreferenceToTile(Activity activity, Preference pref, Tile tile, String key);
+    void bindPreferenceToTile(Activity activity, Preference pref, Tile tile, String key,
+            int baseOrder);
 
     /**
      * Returns a {@link ProgressiveDisclosureMixin} for specified fragment.
      */
     ProgressiveDisclosureMixin getProgressiveDisclosureMixin(Context context,
             DashboardFragment fragment);
+
 }

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

@@ -80,7 +80,8 @@ public class DashboardFeatureProviderImpl implements DashboardFeatureProvider {
     }
 
     @Override
-    public void bindPreferenceToTile(Activity activity, Preference pref, Tile tile, String key) {
+    public void bindPreferenceToTile(Activity activity, Preference pref, Tile tile, String key,
+            int baseOrder) {
         pref.setTitle(tile.title);
         if (!TextUtils.isEmpty(key)) {
             pref.setKey(key);
@@ -112,11 +113,21 @@ public class DashboardFeatureProviderImpl implements DashboardFeatureProvider {
                 return true;
             });
         }
+        final String skipOffsetPackageName = activity.getPackageName();
         // Use negated priority for order, because tile priority is based on intent-filter
         // (larger value has higher priority). However pref order defines smaller value has
         // higher priority.
         if (tile.priority != 0) {
-            pref.setOrder(-tile.priority);
+            boolean shouldSkipBaseOrderOffset = false;
+            if (tile.intent != null) {
+                shouldSkipBaseOrderOffset = TextUtils.equals(
+                        skipOffsetPackageName, tile.intent.getComponent().getPackageName());
+            }
+            if (shouldSkipBaseOrderOffset || baseOrder == Preference.DEFAULT_ORDER) {
+                pref.setOrder(-tile.priority);
+            } else {
+                pref.setOrder(-tile.priority + baseOrder);
+            }
         }
     }
 

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

@@ -62,6 +62,7 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
 
     protected ProgressiveDisclosureMixin mProgressiveDisclosureMixin;
     protected DashboardFeatureProvider mDashboardFeatureProvider;
+    private DashboardTilePlaceholderPreferenceController mPlaceholderPreferenceController;
     private boolean mListeningToCategoryChange;
     private SummaryLoader mSummaryLoader;
 
@@ -74,10 +75,13 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
                 .getProgressiveDisclosureMixin(context, this);
         getLifecycle().addObserver(mProgressiveDisclosureMixin);
 
-        final List<PreferenceController> controllers = getPreferenceControllers(context);
+        List<PreferenceController> controllers = getPreferenceControllers(context);
         if (controllers == null) {
-            return;
+            controllers = new ArrayList<>();
         }
+        mPlaceholderPreferenceController =
+                new DashboardTilePlaceholderPreferenceController(context);
+        controllers.add(mPlaceholderPreferenceController);
         for (PreferenceController controller : controllers) {
             addPreferenceController(controller);
         }
@@ -319,12 +323,13 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
                 // Have the key already, will rebind.
                 final Preference preference = mProgressiveDisclosureMixin.findPreference(
                         screen, key);
-                mDashboardFeatureProvider.bindPreferenceToTile(
-                        getActivity(), preference, tile, key);
+                mDashboardFeatureProvider.bindPreferenceToTile(getActivity(), preference, tile, key,
+                        mPlaceholderPreferenceController.getOrder());
             } else {
                 // Don't have this key, add it.
                 final Preference pref = new Preference(getPrefContext());
-                mDashboardFeatureProvider.bindPreferenceToTile(getActivity(), pref, tile, key);
+                mDashboardFeatureProvider.bindPreferenceToTile(getActivity(), pref, tile, key,
+                        mPlaceholderPreferenceController.getOrder());
                 mProgressiveDisclosureMixin.addPreference(screen, pref);
                 mDashboardTilePrefKeys.add(key);
             }

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

@@ -0,0 +1,68 @@
+/*
+ * 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.dashboard;
+
+import android.content.Context;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceScreen;
+
+import com.android.settings.core.PreferenceController;
+
+/**
+ * PreferenceController for a dashboard_tile_placeholder, a special preference marking where
+ * dynamic dashboard tiles should be injected in a screen. It is optional when building
+ * preference screen in xml. If not present, all dynamic dashboard tiles will be added to the
+ * bottom of page.
+ */
+class DashboardTilePlaceholderPreferenceController extends PreferenceController {
+
+    private static final String KEY_PLACEHOLDER = "dashboard_tile_placeholder";
+
+    private int mOrder = Preference.DEFAULT_ORDER;
+
+    public DashboardTilePlaceholderPreferenceController(Context context) {
+        super(context);
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        final Preference pref = screen.findPreference(getPreferenceKey());
+        if (pref != null) {
+            mOrder = pref.getOrder();
+            screen.removePreference(pref);
+        }
+    }
+
+    @Override
+    public boolean isAvailable() {
+        return false;
+    }
+
+    @Override
+    public boolean handlePreferenceTreeClick(Preference preference) {
+        return false;
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return KEY_PLACEHOLDER;
+    }
+
+    public int getOrder() {
+        return mOrder;
+    }
+}