Elicit ItemsData class and add DiffUtil.Callback

In the previous version, when there is a minor change in data, we
will refresh the whole screen(and data) by invoking "recountItems"
and "notifyDataSetChanged", which did lots of unnecessary works.

In this new cl, I elicit ItemsData class, which encapsulates the list
data used in adapter. When data changed, I build another ItemsData and
use the DiffUtil.Callback to calculate diffs between ItemsDatas. In
this way we can only refresh the items that changed in adapter.

Since I cannot find usage of see_all.xml anymore, I delete the relevant
code as well as the resource files.

Bug: 30319913
Test: make RunSettingsRoboTests
Change-Id: I4f753a26f624affea6c6c35d49cfb9c43fb74fe6

res/layout/see_all.xml

@@ -1,65 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (C) 2015 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.
--->
-
-<LinearLayout
-        xmlns:android="http://schemas.android.com/apk/res/android"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:background="?android:attr/selectableItemBackground"
-        android:gravity="center_vertical"
-        android:minHeight="@dimen/dashboard_tile_minimum_height"
-        android:clickable="true"
-        android:focusable="true">
-
-    <View
-            android:layout_width="@dimen/dashboard_tile_image_size"
-            android:layout_height="@dimen/dashboard_tile_image_size"
-            android:layout_marginStart="@dimen/dashboard_tile_image_margin_start"
-            android:layout_marginEnd="@dimen/dashboard_tile_image_margin_end"
-            android:visibility="invisible" />
-
-    <LinearLayout
-            android:layout_width="match_parent"
-            android:layout_height="match_parent"
-            android:orientation="vertical">
-
-        <LinearLayout
-            android:layout_width="match_parent"
-            android:layout_height="0dip"
-            android:orientation="vertical"
-            android:gravity="center_vertical"
-            android:layout_weight="1">
-
-            <RelativeLayout
-                    android:layout_width="wrap_content"
-                    android:layout_height="wrap_content">
-
-                <TextView android:id="@android:id/title"
-                          android:layout_width="wrap_content"
-                          android:layout_height="wrap_content"
-                          android:singleLine="true"
-                          android:textAppearance="@android:style/TextAppearance.Material.Widget.Button.Inverse"
-                          android:textColor="?android:attr/colorAccent"
-                          android:ellipsize="marquee"
-                          android:fadingEdge="horizontal" />
-
-            </RelativeLayout>
-
-        </LinearLayout>
-
-    </LinearLayout>
-
-</LinearLayout>

res/values/strings.xml

@@ -7281,11 +7281,6 @@
     <!-- Conversation message timestamp of the messaging app preview screen. [CHAR LIMIT=20] -->
     <string name="screen_zoom_conversation_timestamp_4">Tue 6:03PM</string>
 
-    <!-- Button to show all top-level settings items [CHAR LIMIT=20] -->
-    <string name="see_all">See all</string>
-    <!-- Button to show less top-level settings items [CHAR LIMIT=20] -->
-    <string name="see_less">See less</string>
-
     <!-- Wi-Fi state - Disconnected [CHAR LIMIT=NONE] -->
     <string name="disconnected">Disconnected</string>
 

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

@@ -20,6 +20,7 @@ import android.content.pm.PackageManager;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.Icon;
 import android.os.Bundle;
+import android.support.v7.util.DiffUtil;
 import android.support.v7.widget.PopupMenu;
 import android.support.v7.widget.RecyclerView;
 import android.text.TextUtils;
@@ -34,7 +35,6 @@ import android.widget.ImageView;
 import android.widget.TextView;
 
 import com.android.internal.logging.MetricsProto.MetricsEvent;
-import com.android.internal.util.ArrayUtils;
 import com.android.settings.R;
 import com.android.settings.SettingsActivity;
 import com.android.settings.core.instrumentation.MetricsFeatureProvider;
@@ -48,82 +48,92 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class DashboardAdapter extends RecyclerView.Adapter<DashboardAdapter.DashboardItemHolder>
-        implements View.OnClickListener, SummaryLoader.SummaryConsumer {
+        implements SummaryLoader.SummaryConsumer {
     public static final String TAG = "DashboardAdapter";
     private static final String STATE_SUGGESTION_LIST = "suggestion_list";
     private static final String STATE_CATEGORY_LIST = "category_list";
-    private static final String STATE_IS_SHOWING_ALL = "is_showing_all";
     private static final String STATE_SUGGESTION_MODE = "suggestion_mode";
-    private static final int NS_SPACER = 0;
-    private static final int NS_SUGGESTION = 1000;
-    private static final int NS_ITEMS = 2000;
-    private static final int NS_CONDITION = 3000;
 
-    private static int SUGGESTION_MODE_DEFAULT = 0;
-    private static int SUGGESTION_MODE_COLLAPSED = 1;
-    private static int SUGGESTION_MODE_EXPANDED = 2;
-
-    private static final int DEFAULT_SUGGESTION_COUNT = 2;
-
-    private final List<Object> mItems = new ArrayList<>();
-    private final List<Integer> mTypes = new ArrayList<>();
-    private final List<Integer> mIds = new ArrayList<>();
     private final IconCache mCache;
-
     private final Context mContext;
     private final MetricsFeatureProvider mMetricsFeatureProvider;
-
+    private DashboardData mDashboardData;
-    private List<DashboardCategory> mCategories;
-    private List<Condition> mConditions;
-    private List<Tile> mSuggestions;
-
-    private boolean mIsShowingAll;
-    // Used for counting items;
-    private int mId;
-
-    private int mSuggestionMode = SUGGESTION_MODE_DEFAULT;
-
-    private Condition mExpandedCondition = null;
     private SuggestionParser mSuggestionParser;
 
+    private View.OnClickListener mTileClickListener = new View.OnClickListener() {
+        @Override
+        public void onClick(View v) {
+            //TODO: get rid of setTag/getTag
+            final Tile tile = (Tile) mDashboardData.getItemEntityByPosition((int) v.getTag());
+            ((SettingsActivity) mContext).openTile(tile);
+        }
+    };
+
+    private View.OnClickListener mConditionClickListener = new View.OnClickListener() {
+
+        @Override
+        public void onClick(View v) {
+            Condition expandedCondition = mDashboardData.getExpandedCondition();
+
+            //TODO: get rid of setTag/getTag
+            if (v.getTag() == expandedCondition) {
+                mMetricsFeatureProvider.action(mContext,
+                        MetricsEvent.ACTION_SETTINGS_CONDITION_CLICK,
+                        expandedCondition.getMetricsConstant());
+                expandedCondition.onPrimaryClick();
+            } else {
+                expandedCondition = (Condition) v.getTag();
+                mMetricsFeatureProvider.action(mContext,
+                        MetricsEvent.ACTION_SETTINGS_CONDITION_EXPAND,
+                        expandedCondition.getMetricsConstant());
+
+                updateExpandedCondition(expandedCondition);
+            }
+        }
+    };
+
     public DashboardAdapter(Context context, SuggestionParser parser,
             MetricsFeatureProvider metricsFeatureProvider, Bundle savedInstanceState,
             List<Condition> conditions) {
+        List<Tile> suggestions = null;
+        List<DashboardCategory> categories = null;
+        int suggestionMode = DashboardData.SUGGESTION_MODE_DEFAULT;
+
         mContext = context;
         mMetricsFeatureProvider = metricsFeatureProvider;
         mCache = new IconCache(context);
         mSuggestionParser = parser;
-        mConditions = conditions;
 
         setHasStableIds(true);
 
-        boolean showAll = true;
         if (savedInstanceState != null) {
-            mSuggestions = savedInstanceState.getParcelableArrayList(STATE_SUGGESTION_LIST);
+            suggestions = savedInstanceState.getParcelableArrayList(STATE_SUGGESTION_LIST);
-            mCategories = savedInstanceState.getParcelableArrayList(STATE_CATEGORY_LIST);
+            categories = savedInstanceState.getParcelableArrayList(STATE_CATEGORY_LIST);
-            showAll = savedInstanceState.getBoolean(STATE_IS_SHOWING_ALL, true);
+            suggestionMode = savedInstanceState.getInt(
-            mSuggestionMode = savedInstanceState.getInt(
+                    STATE_SUGGESTION_MODE, DashboardData.SUGGESTION_MODE_DEFAULT);
-                    STATE_SUGGESTION_MODE, SUGGESTION_MODE_DEFAULT);
         }
-        setShowingAll(showAll);
+
+        mDashboardData = new DashboardData.Builder()
+                .setConditions(conditions)
+                .setSuggestions(suggestions)
+                .setCategories(categories)
+                .setSuggestionMode(suggestionMode)
+                .build();
     }
 
     public List<Tile> getSuggestions() {
-        return mSuggestions;
+        return mDashboardData.getSuggestions();
     }
 
     public void setCategoriesAndSuggestions(List<DashboardCategory> categories,
             List<Tile> suggestions) {
-        mSuggestions = suggestions;
-        mCategories = categories;
-
         // TODO: Better place for tinting?
         TypedValue tintColor = new TypedValue();
         mContext.getTheme().resolveAttribute(com.android.internal.R.attr.colorAccent,
                 tintColor, true);
         for (int i = 0; i < categories.size(); i++) {
             for (int j = 0; j < categories.get(i).tiles.size(); j++) {
-                Tile tile = categories.get(i).tiles.get(j);
+                final Tile tile = categories.get(i).tiles.get(j);
 
                 if (!mContext.getPackageName().equals(
                         tile.intent.getComponent().getPackageName())) {
@@ -133,85 +143,49 @@ public class DashboardAdapter extends RecyclerView.Adapter<DashboardAdapter.Dash
                 }
             }
         }
-        recountItems();
+
+        final DashboardData prevData = mDashboardData;
+        mDashboardData = new DashboardData.Builder(prevData)
+                .setSuggestions(suggestions)
+                .setCategories(categories)
+                .build();
+        notifyDashboardDataChanged(prevData);
     }
 
     public void setConditions(List<Condition> conditions) {
-        mConditions = conditions;
+        final DashboardData prevData = mDashboardData;
-        recountItems();
+        mDashboardData = new DashboardData.Builder(prevData)
+                .setConditions(conditions)
+                .build();
+        notifyDashboardDataChanged(prevData);
     }
 
     @Override
     public void notifySummaryChanged(Tile tile) {
-        notifyDataSetChanged();
+        final int position = mDashboardData.getPositionByTile(tile);
+        if (position != DashboardData.POSITION_NOT_FOUND) {
+            final Tile targetTile = (Tile) mDashboardData.getItemEntityByPosition(position);
+            if (!TextUtils.equals(tile.summary, targetTile.summary)) {
+
+                // Since usually tile in parameter and tile in mCategories are same instance,
+                // which is hard to be detected by DiffUtil, so we notifyItemChanged directly.
+                notifyItemChanged(position);
+            }
+        }
     }
 
-    public void setShowingAll(boolean showingAll) {
+    // TODO: move this method to SuggestionParser or some other util class
-        mIsShowingAll = showingAll;
+    public void disableSuggestion(Tile suggestion) {
-        recountItems();
+        if (mSuggestionParser == null) {
+            return;
         }
-
+        if (mSuggestionParser.dismissSuggestion(suggestion)) {
-    private void recountItems() {
+            mContext.getPackageManager().setComponentEnabledSetting(
-        reset();
+                    suggestion.intent.getComponent(),
-        boolean hasConditions = false;
+                    PackageManager.COMPONENT_ENABLED_STATE_DISABLED,
-        for (int i = 0; mConditions != null && i < mConditions.size(); i++) {
+                    PackageManager.DONT_KILL_APP);
-            boolean shouldShow = mConditions.get(i).shouldShow();
+            mSuggestionParser.markCategoryDone(suggestion.category);
-            hasConditions |= shouldShow;
-            countItem(mConditions.get(i), R.layout.condition_card, shouldShow, NS_CONDITION);
         }
-        boolean hasSuggestions = mSuggestions != null && mSuggestions.size() != 0;
-        countItem(null, R.layout.dashboard_spacer, hasConditions && hasSuggestions, NS_SPACER);
-        countItem(null, R.layout.suggestion_header, hasSuggestions, NS_SPACER);
-        resetCount();
-        if (mSuggestions != null) {
-            int maxSuggestions = getDisplayableSuggestionCount();
-            for (int i = 0; i < mSuggestions.size(); i++) {
-                countItem(mSuggestions.get(i), R.layout.suggestion_tile, i < maxSuggestions,
-                        NS_SUGGESTION);
-            }
-        }
-        resetCount();
-        for (int i = 0; mCategories != null && i < mCategories.size(); i++) {
-            DashboardCategory category = mCategories.get(i);
-            countItem(category, R.layout.dashboard_category, mIsShowingAll
-                    && !TextUtils.isEmpty(category.title), NS_ITEMS);
-            for (int j = 0; j < category.tiles.size(); j++) {
-                Tile tile = category.tiles.get(j);
-                countItem(tile, R.layout.dashboard_tile, mIsShowingAll
-                        || ArrayUtils.contains(DashboardSummary.INITIAL_ITEMS,
-                        tile.intent.getComponent().getClassName()), NS_ITEMS);
-            }
-        }
-        notifyDataSetChanged();
-    }
-
-    private void resetCount() {
-        mId = 0;
-    }
-
-    private void reset() {
-        mItems.clear();
-        mTypes.clear();
-        mIds.clear();
-        mId = 0;
-    }
-
-    private void countItem(Object object, int type, boolean add, int nameSpace) {
-        if (add) {
-            mItems.add(object);
-            mTypes.add(type);
-            // TODO: Counting namespaces for handling of suggestions/conds appearing/disappearing.
-            mIds.add(mId + nameSpace);
-        }
-        mId++;
-    }
-
-    private int getDisplayableSuggestionCount() {
-        final int suggestionSize = mSuggestions.size();
-        return mSuggestionMode == SUGGESTION_MODE_DEFAULT
-                ? Math.min(DEFAULT_SUGGESTION_COUNT, suggestionSize)
-                : mSuggestionMode == SUGGESTION_MODE_EXPANDED
-                        ? suggestionSize : 0;
     }
 
     @Override
@@ -222,21 +196,24 @@ public class DashboardAdapter extends RecyclerView.Adapter<DashboardAdapter.Dash
 
     @Override
     public void onBindViewHolder(DashboardItemHolder holder, int position) {
-        switch (mTypes.get(position)) {
+        final int type = mDashboardData.getItemTypeByPosition(position);
+        switch (type) {
             case R.layout.dashboard_category:
-                onBindCategory(holder, (DashboardCategory) mItems.get(position));
+                onBindCategory(holder,
+                        (DashboardCategory) mDashboardData.getItemEntityByPosition(position));
                 break;
             case R.layout.dashboard_tile:
-                final Tile tile = (Tile) mItems.get(position);
+                final Tile tile = (Tile) mDashboardData.getItemEntityByPosition(position);
                 onBindTile(holder, tile);
-                holder.itemView.setTag(tile);
+                holder.itemView.setTag(position);
-                holder.itemView.setOnClickListener(this);
+                holder.itemView.setOnClickListener(mTileClickListener);
                 break;
             case R.layout.suggestion_header:
-                onBindSuggestionHeader(holder);
+                onBindSuggestionHeader(holder, (DashboardData.SuggestionHeaderData)
+                        mDashboardData.getItemEntityByPosition(position));
                 break;
             case R.layout.suggestion_tile:
-                final Tile suggestion = (Tile) mItems.get(position);
+                final Tile suggestion = (Tile) mDashboardData.getItemEntityByPosition(position);
                 onBindTile(holder, suggestion);
                 holder.itemView.setOnClickListener(new View.OnClickListener() {
                     @Override
@@ -255,12 +232,12 @@ public class DashboardAdapter extends RecyclerView.Adapter<DashboardAdapter.Dash
                             }
                         });
                 break;
-            case R.layout.see_all:
-                onBindSeeAll(holder);
-                break;
             case R.layout.condition_card:
-                ConditionAdapterUtils.bindViews((Condition) mItems.get(position), holder,
+                final boolean isExpanded = mDashboardData.getItemEntityByPosition(position)
-                        mItems.get(position) == mExpandedCondition, this,
+                        == mDashboardData.getExpandedCondition();
+                ConditionAdapterUtils.bindViews(
+                        (Condition) mDashboardData.getItemEntityByPosition(position),
+                        holder, isExpanded, mConditionClickListener,
                         new View.OnClickListener() {
                             @Override
                             public void onClick(View v) {
@@ -271,8 +248,71 @@ public class DashboardAdapter extends RecyclerView.Adapter<DashboardAdapter.Dash
         }
     }
 
+    @Override
+    public long getItemId(int position) {
+        return mDashboardData.getItemIdByPosition(position);
+    }
+
+    @Override
+    public int getItemViewType(int position) {
+        return mDashboardData.getItemTypeByPosition(position);
+    }
+
+    @Override
+    public int getItemCount() {
+        return mDashboardData.size();
+    }
+
+    public void onExpandClick(View v) {
+        Condition expandedCondition = mDashboardData.getExpandedCondition();
+        if (v.getTag() == expandedCondition) {
+            mMetricsFeatureProvider.action(mContext,
+                    MetricsEvent.ACTION_SETTINGS_CONDITION_COLLAPSE,
+                    expandedCondition.getMetricsConstant());
+            expandedCondition = null;
+        } else {
+            expandedCondition = (Condition) v.getTag();
+            mMetricsFeatureProvider.action(mContext, MetricsEvent.ACTION_SETTINGS_CONDITION_EXPAND,
+                    expandedCondition.getMetricsConstant());
+        }
+
+        updateExpandedCondition(expandedCondition);
+    }
+
+    public Object getItem(long itemId) {
+        return mDashboardData.getItemEntityById(itemId);
+    }
+
+    public static String getSuggestionIdentifier(Context context, Tile suggestion) {
+        String packageName = suggestion.intent.getComponent().getPackageName();
+        if (packageName.equals(context.getPackageName())) {
+            // Since Settings provides several suggestions, fill in the class instead of the
+            // package for these.
+            packageName = suggestion.intent.getComponent().getClassName();
+        }
+        return packageName;
+    }
+
+    private void notifyDashboardDataChanged(DashboardData prevData) {
+        if (prevData != null) {
+            final DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(new DashboardData
+                    .ItemsDataDiffCallback(prevData.getItemList(), mDashboardData.getItemList()));
+            diffResult.dispatchUpdatesTo(this);
+        } else {
+            notifyDataSetChanged();
+        }
+    }
+
+    private void updateExpandedCondition(Condition condition) {
+        final DashboardData prevData = mDashboardData;
+        mDashboardData = new DashboardData.Builder(prevData)
+                .setExpandedCondition(condition)
+                .build();
+        notifyDashboardDataChanged(prevData);
+    }
+
     private void showRemoveOption(View v, final Tile suggestion) {
-        PopupMenu popup = new PopupMenu(
+        final PopupMenu popup = new PopupMenu(
                 new ContextThemeWrapper(mContext, R.style.Theme_AppCompat_DayNight), v);
         popup.getMenu().add(R.string.suggestion_remove).setOnMenuItemClickListener(
                 new MenuItem.OnMenuItemClickListener() {
@@ -282,34 +322,29 @@ public class DashboardAdapter extends RecyclerView.Adapter<DashboardAdapter.Dash
                                 mContext, MetricsEvent.ACTION_SETTINGS_DISMISS_SUGGESTION,
                                 DashboardAdapter.getSuggestionIdentifier(mContext, suggestion));
                         disableSuggestion(suggestion);
-                mSuggestions.remove(suggestion);
+                        List<Tile> suggestions = mDashboardData.getSuggestions();
-                recountItems();
+                        suggestions.remove(suggestion);
+
+                        DashboardData prevData = mDashboardData;
+                        mDashboardData = new DashboardData.Builder(prevData)
+                                .setSuggestions(suggestions)
+                                .build();
+                        notifyDashboardDataChanged(prevData);
+
                         return true;
                     }
                 });
         popup.show();
     }
 
-    public void disableSuggestion(Tile suggestion) {
+    private void onBindSuggestionHeader(final DashboardItemHolder holder, DashboardData
-        if (mSuggestionParser == null) {
+            .SuggestionHeaderData data) {
-            return;
+        final boolean moreSuggestions = data.hasMoreSuggestions;
-        }
+        final int undisplayedSuggestionCount = data.undisplayedSuggestionCount;
-        if (mSuggestionParser.dismissSuggestion(suggestion)) {
-            mContext.getPackageManager().setComponentEnabledSetting(
-                    suggestion.intent.getComponent(),
-                    PackageManager.COMPONENT_ENABLED_STATE_DISABLED,
-                    PackageManager.DONT_KILL_APP);
-            mSuggestionParser.markCategoryDone(suggestion.category);
-        }
-    }
 
-    private void onBindSuggestionHeader(final DashboardItemHolder holder) {
-        final boolean moreSuggestions = hasMoreSuggestions();
-        final int undisplayedSuggestionCount =
-                mSuggestions.size() - getDisplayableSuggestionCount();
         holder.icon.setImageResource(moreSuggestions ? R.drawable.ic_expand_more
                 : R.drawable.ic_expand_less);
-        holder.title.setText(mContext.getString(R.string.suggestions_title, mSuggestions.size()));
+        holder.title.setText(mContext.getString(R.string.suggestions_title, data.suggestionSize));
         String summaryContentDescription;
         if (moreSuggestions) {
             summaryContentDescription = mContext.getResources().getQuantityString(
@@ -329,20 +364,20 @@ public class DashboardAdapter extends RecyclerView.Adapter<DashboardAdapter.Dash
         holder.itemView.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
-                if (hasMoreSuggestions()) {
+                final int suggestionMode;
-                    mSuggestionMode = SUGGESTION_MODE_EXPANDED;
+                if (moreSuggestions) {
+                    suggestionMode = DashboardData.SUGGESTION_MODE_EXPANDED;
                 } else {
-                    mSuggestionMode = SUGGESTION_MODE_COLLAPSED;
+                    suggestionMode = DashboardData.SUGGESTION_MODE_COLLAPSED;
-                }
-                recountItems();
-            }
-        });
                 }
 
-    private boolean hasMoreSuggestions() {
+                DashboardData prevData = mDashboardData;
-        return mSuggestionMode == SUGGESTION_MODE_COLLAPSED
+                mDashboardData = new DashboardData.Builder(prevData)
-                || (mSuggestionMode == SUGGESTION_MODE_DEFAULT
+                        .setSuggestionMode(suggestionMode)
-                && mSuggestions.size() > DEFAULT_SUGGESTION_COUNT);
+                        .build();
+                notifyDashboardDataChanged(prevData);
+            }
+        });
     }
 
     private void onBindTile(DashboardItemHolder holder, Tile tile) {
@@ -360,98 +395,21 @@ public class DashboardAdapter extends RecyclerView.Adapter<DashboardAdapter.Dash
         holder.title.setText(category.title);
     }
 
-    private void onBindSeeAll(DashboardItemHolder holder) {
-        holder.title.setText(mIsShowingAll ? R.string.see_less
-                : R.string.see_all);
-        holder.itemView.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View v) {
-                setShowingAll(!mIsShowingAll);
-            }
-        });
-    }
-
-    @Override
-    public long getItemId(int position) {
-        return mIds.get(position);
-    }
-
-    @Override
-    public int getItemViewType(int position) {
-        return mTypes.get(position);
-    }
-
-    @Override
-    public int getItemCount() {
-        return mIds.size();
-    }
-
-    @Override
-    public void onClick(View v) {
-        if (v.getId() == R.id.dashboard_tile) {
-            ((SettingsActivity) mContext).openTile((Tile) v.getTag());
-            return;
-        }
-        if (v.getTag() == mExpandedCondition) {
-            mMetricsFeatureProvider.action(mContext, MetricsEvent.ACTION_SETTINGS_CONDITION_CLICK,
-                    mExpandedCondition.getMetricsConstant());
-            mExpandedCondition.onPrimaryClick();
-        } else {
-            mExpandedCondition = (Condition) v.getTag();
-            mMetricsFeatureProvider.action(mContext, MetricsEvent.ACTION_SETTINGS_CONDITION_EXPAND,
-                    mExpandedCondition.getMetricsConstant());
-            notifyDataSetChanged();
-        }
-    }
-
-    public void onExpandClick(View v) {
-        if (v.getTag() == mExpandedCondition) {
-            mMetricsFeatureProvider.action(mContext,
-                    MetricsEvent.ACTION_SETTINGS_CONDITION_COLLAPSE,
-                    mExpandedCondition.getMetricsConstant());
-            mExpandedCondition = null;
-        } else {
-            mExpandedCondition = (Condition) v.getTag();
-            mMetricsFeatureProvider.action(mContext, MetricsEvent.ACTION_SETTINGS_CONDITION_EXPAND,
-                    mExpandedCondition.getMetricsConstant());
-        }
-        notifyDataSetChanged();
-    }
-
-    public Object getItem(long itemId) {
-        for (int i = 0; i < mIds.size(); i++) {
-            if (mIds.get(i) == itemId) {
-                return mItems.get(i);
-            }
-        }
-        return null;
-    }
-
-    public static String getSuggestionIdentifier(Context context, Tile suggestion) {
-        String packageName = suggestion.intent.getComponent().getPackageName();
-        if (packageName.equals(context.getPackageName())) {
-            // Since Settings provides several suggestions, fill in the class instead of the
-            // package for these.
-            packageName = suggestion.intent.getComponent().getClassName();
-        }
-        return packageName;
-    }
-
     void onSaveInstanceState(Bundle outState) {
-        if (mSuggestions != null) {
+        final List<Tile> suggestions = mDashboardData.getSuggestions();
+        final List<DashboardCategory> categories = mDashboardData.getCategories();
+        if (suggestions != null) {
             outState.putParcelableArrayList(STATE_SUGGESTION_LIST,
-                    new ArrayList<Tile>(mSuggestions));
+                    new ArrayList<Tile>(suggestions));
         }
-        if (mCategories != null) {
+        if (categories != null) {
             outState.putParcelableArrayList(STATE_CATEGORY_LIST,
-                    new ArrayList<DashboardCategory>(mCategories));
+                    new ArrayList<DashboardCategory>(categories));
         }
-        outState.putBoolean(STATE_IS_SHOWING_ALL, mIsShowingAll);
+        outState.putInt(STATE_SUGGESTION_MODE, mDashboardData.getSuggestionMode());
-        outState.putInt(STATE_SUGGESTION_MODE, mSuggestionMode);
     }
 
     private static class IconCache {
-
         private final Context mContext;
         private final ArrayMap<Icon, Drawable> mMap = new ArrayMap<>();
 

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

@@ -0,0 +1,488 @@
+/*
+ * 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.annotation.IntDef;
+import android.support.v7.util.DiffUtil;
+import android.text.TextUtils;
+import com.android.settings.dashboard.conditional.Condition;
+import com.android.settingslib.drawer.DashboardCategory;
+import com.android.settingslib.drawer.Tile;
+import com.android.settings.R;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Description about data list used in the DashboardAdapter. In the data list each item can be
+ * Condition, suggestion or category tile.
+ * <p>
+ * ItemsData has inner class Item, which represents the Item in data list.
+ */
+public class DashboardData {
+    public static final int SUGGESTION_MODE_DEFAULT = 0;
+    public static final int SUGGESTION_MODE_COLLAPSED = 1;
+    public static final int SUGGESTION_MODE_EXPANDED = 2;
+    public static final int POSITION_NOT_FOUND = -1;
+    public static final int DEFAULT_SUGGESTION_COUNT = 2;
+
+    // id namespace for different type of items.
+    private static final int NS_SPACER = 0;
+    private static final int NS_SUGGESTION = 1000;
+    private static final int NS_ITEMS = 2000;
+    private static final int NS_CONDITION = 3000;
+
+    private final List<Item> mItems;
+    private final List<DashboardCategory> mCategories;
+    private final List<Condition> mConditions;
+    private final List<Tile> mSuggestions;
+    private final int mSuggestionMode;
+    private final Condition mExpandedCondition;
+    private int mId;
+
+    private DashboardData(Builder builder) {
+        mCategories = builder.mCategories;
+        mConditions = builder.mConditions;
+        mSuggestions = builder.mSuggestions;
+        mSuggestionMode = builder.mSuggestionMode;
+        mExpandedCondition = builder.mExpandedCondition;
+
+        mItems = new ArrayList<>();
+        mId = 0;
+
+        buildItemsData();
+    }
+
+    public int getItemIdByPosition(int position) {
+        return mItems.get(position).id;
+    }
+
+    public int getItemTypeByPosition(int position) {
+        return mItems.get(position).type;
+    }
+
+    public Object getItemEntityByPosition(int position) {
+        return mItems.get(position).entity;
+    }
+
+    public List<Item> getItemList() {
+        return mItems;
+    }
+
+    public int size() {
+        return mItems.size();
+    }
+
+    public Object getItemEntityById(long id) {
+        for (final Item item : mItems) {
+            if (item.id == id) {
+                return item.entity;
+            }
+        }
+        return null;
+    }
+
+    public List<DashboardCategory> getCategories() {
+        return mCategories;
+    }
+
+    public List<Condition> getConditions() {
+        return mConditions;
+    }
+
+    public List<Tile> getSuggestions() {
+        return mSuggestions;
+    }
+
+    public int getSuggestionMode() {
+        return mSuggestionMode;
+    }
+
+    public Condition getExpandedCondition() {
+        return mExpandedCondition;
+    }
+
+    /**
+     * Find the position of the object in mItems list, using the equals method to compare
+     *
+     * @param entity the object that need to be found in list
+     * @return position of the object, return POSITION_NOT_FOUND if object isn't in the list
+     */
+    public int getPositionByEntity(Object entity) {
+        if (entity == null) return POSITION_NOT_FOUND;
+
+        final int size = mItems.size();
+        for (int i = 0; i < size; i++) {
+            final Object item = mItems.get(i).entity;
+            if (entity.equals(item)) {
+                return i;
+            }
+        }
+
+        return POSITION_NOT_FOUND;
+    }
+
+    /**
+     * Find the position of the Tile object.
+     * <p>
+     * First, try to find the exact identical instance of the tile object, if not found,
+     * then try to find a tile has the same title.
+     *
+     * @param tile tile that need to be found
+     * @return position of the object, return INDEX_NOT_FOUND if object isn't in the list
+     */
+    public int getPositionByTile(Tile tile) {
+        final int size = mItems.size();
+        for (int i = 0; i < size; i++) {
+            final Object entity = mItems.get(i).entity;
+            if (entity == tile) {
+                return i;
+            } else if (entity instanceof Tile && tile.title.equals(((Tile) entity).title)) {
+                return i;
+            }
+        }
+
+        return POSITION_NOT_FOUND;
+    }
+
+    /**
+     * Get the count of suggestions to display
+     *
+     * The displayable count mainly depends on the {@link #mSuggestionMode}
+     * and the size of suggestions list.
+     *
+     * When in default mode, displayable count couldn't larger than
+     * {@link #DEFAULT_SUGGESTION_COUNT}.
+     *
+     * When in expanded mode, display all the suggestions.
+     * @return the count of suggestions to display
+     */
+    public int getDisplayableSuggestionCount() {
+        final int suggestionSize = mSuggestions.size();
+        return mSuggestionMode == SUGGESTION_MODE_DEFAULT
+                ? Math.min(DEFAULT_SUGGESTION_COUNT, suggestionSize)
+                : mSuggestionMode == SUGGESTION_MODE_EXPANDED
+                ? suggestionSize : 0;
+    }
+
+    public boolean hasMoreSuggestions() {
+        return mSuggestionMode == SUGGESTION_MODE_COLLAPSED
+                || (mSuggestionMode == SUGGESTION_MODE_DEFAULT
+                && mSuggestions.size() > DEFAULT_SUGGESTION_COUNT);
+    }
+
+    private void resetCount() {
+        mId = 0;
+    }
+
+    /**
+     * Count the item and add it into list when {@paramref add} is true.
+     *
+     * Note that {@link #mId} will increment automatically and the real
+     * id stored in {@link Item} is shifted by {@paramref nameSpace}. This is a
+     * simple way to keep the id stable.
+     *
+     * @param object maybe {@link Condition}, {@link Tile}, {@link DashboardCategory} or null
+     * @param type type of the item, and value is the layout id
+     * @param add  flag about whether to add item into list
+     * @param nameSpace namespace based on the type
+     */
+    private void countItem(Object object, int type, boolean add, int nameSpace) {
+        if (add) {
+            mItems.add(new Item(object, type, mId + nameSpace, object == mExpandedCondition));
+        }
+        mId++;
+    }
+
+    /**
+     * Build the mItems list using mConditions, mSuggestions, mCategories data
+     * and mIsShowingAll, mSuggestionMode flag.
+     */
+    private void buildItemsData() {
+        boolean hasConditions = false;
+        for (int i = 0; mConditions != null && i < mConditions.size(); i++) {
+            boolean shouldShow = mConditions.get(i).shouldShow();
+            hasConditions |= shouldShow;
+            countItem(mConditions.get(i), R.layout.condition_card, shouldShow, NS_CONDITION);
+        }
+
+        resetCount();
+        final boolean hasSuggestions = mSuggestions != null && mSuggestions.size() != 0;
+        countItem(null, R.layout.dashboard_spacer, hasConditions && hasSuggestions, NS_SPACER);
+        countItem(buildSuggestionHeaderData(), R.layout.suggestion_header, hasSuggestions,
+                NS_SPACER);
+
+        resetCount();
+        if (mSuggestions != null) {
+            int maxSuggestions = getDisplayableSuggestionCount();
+            for (int i = 0; i < mSuggestions.size(); i++) {
+                countItem(mSuggestions.get(i), R.layout.suggestion_tile, i < maxSuggestions,
+                        NS_SUGGESTION);
+            }
+        }
+        resetCount();
+        for (int i = 0; mCategories != null && i < mCategories.size(); i++) {
+            DashboardCategory category = mCategories.get(i);
+            countItem(category, R.layout.dashboard_category,
+                    !TextUtils.isEmpty(category.title), NS_ITEMS);
+            for (int j = 0; j < category.tiles.size(); j++) {
+                Tile tile = category.tiles.get(j);
+                countItem(tile, R.layout.dashboard_tile, true, NS_ITEMS);
+            }
+        }
+    }
+
+    private SuggestionHeaderData buildSuggestionHeaderData() {
+        SuggestionHeaderData data;
+        if (mSuggestions == null) {
+            data = new SuggestionHeaderData();
+        } else {
+            final boolean hasMoreSuggestions = hasMoreSuggestions();
+            final int suggestionSize = mSuggestions.size();
+            final int undisplayedSuggestionCount = suggestionSize - getDisplayableSuggestionCount();
+            data = new SuggestionHeaderData(hasMoreSuggestions, suggestionSize,
+                    undisplayedSuggestionCount);
+        }
+
+        return data;
+    }
+
+    /**
+     * Builder used to build the ItemsData
+     * <p>
+     * {@link #mExpandedCondition} and {@link #mSuggestionMode} have default value
+     * while others are not.
+     */
+    public static class Builder {
+        private int mSuggestionMode = SUGGESTION_MODE_DEFAULT;
+        private Condition mExpandedCondition = null;
+
+        private List<DashboardCategory> mCategories;
+        private List<Condition> mConditions;
+        private List<Tile> mSuggestions;
+
+
+        public Builder() {
+        }
+
+        public Builder(DashboardData dashboardData) {
+            mCategories = dashboardData.mCategories;
+            mConditions = dashboardData.mConditions;
+            mSuggestions = dashboardData.mSuggestions;
+            mSuggestionMode = dashboardData.mSuggestionMode;
+            mExpandedCondition = dashboardData.mExpandedCondition;
+        }
+
+        public Builder setCategories(List<DashboardCategory> categories) {
+            this.mCategories = categories;
+            return this;
+        }
+
+        public Builder setConditions(List<Condition> conditions) {
+            this.mConditions = conditions;
+            return this;
+        }
+
+        public Builder setSuggestions(List<Tile> suggestions) {
+            this.mSuggestions = suggestions;
+            return this;
+        }
+
+        public Builder setSuggestionMode(int suggestionMode) {
+            this.mSuggestionMode = suggestionMode;
+            return this;
+        }
+
+        public Builder setExpandedCondition(Condition expandedCondition) {
+            this.mExpandedCondition = expandedCondition;
+            return this;
+        }
+
+        public DashboardData build() {
+            return new DashboardData(this);
+        }
+    }
+
+    /**
+     * A DiffCallback to calculate the difference between old and new Item
+     * List in DashboardData
+     */
+    public static class ItemsDataDiffCallback extends DiffUtil.Callback {
+        final private List<Item> mOldItems;
+        final private List<Item> mNewItems;
+
+        public ItemsDataDiffCallback(List<Item> oldItems, List<Item> newItems) {
+            mOldItems = oldItems;
+            mNewItems = newItems;
+        }
+
+        @Override
+        public int getOldListSize() {
+            return mOldItems.size();
+        }
+
+        @Override
+        public int getNewListSize() {
+            return mNewItems.size();
+        }
+
+        @Override
+        public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
+            return mOldItems.get(oldItemPosition).id == mNewItems.get(newItemPosition).id;
+        }
+
+        @Override
+        public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
+            return mOldItems.get(oldItemPosition).equals(mNewItems.get(newItemPosition));
+        }
+    }
+
+    /**
+     * An item contains the data needed in the DashboardData.
+     */
+    private static class Item {
+        // valid types in field type
+        private static final int TYPE_DASHBOARD_CATEGORY = R.layout.dashboard_category;
+        private static final int TYPE_DASHBOARD_TILE = R.layout.dashboard_tile;
+        private static final int TYPE_SUGGESTION_HEADER = R.layout.suggestion_header;
+        private static final int TYPE_SUGGESTION_TILE = R.layout.suggestion_tile;
+        private static final int TYPE_CONDITION_CARD = R.layout.condition_card;
+        private static final int TYPE_DASHBOARD_SPACER = R.layout.dashboard_spacer;
+
+        @IntDef({TYPE_DASHBOARD_CATEGORY, TYPE_DASHBOARD_TILE, TYPE_SUGGESTION_HEADER,
+                TYPE_SUGGESTION_TILE, TYPE_CONDITION_CARD, TYPE_DASHBOARD_SPACER})
+        @Retention(RetentionPolicy.SOURCE)
+        public @interface ItemTypes{}
+
+        /**
+         * The main data object in item, usually is a {@link Tile}, {@link Condition} or
+         * {@link DashboardCategory} object. This object can also be null when the
+         * item is an divider line. Please refer to {@link #buildItemsData()} for
+         * detail usage of the Item.
+         */
+        public final Object entity;
+
+        /**
+         * The type of item, value inside is the layout id(e.g. R.layout.dashboard_tile)
+         */
+        public final @ItemTypes int type;
+
+        /**
+         * Id of this item, used in the {@link ItemsDataDiffCallback} to identify the same item.
+         */
+        public final int id;
+
+        /**
+         * To store whether the condition is expanded, useless when {@link #type} is not
+         * {@link #TYPE_CONDITION_CARD}
+         */
+        public final boolean conditionExpanded;
+
+        public Item(Object entity, @ItemTypes int type, int id, boolean conditionExpanded) {
+            this.entity = entity;
+            this.type = type;
+            this.id = id;
+            this.conditionExpanded = conditionExpanded;
+        }
+
+        /**
+         * Override it to make comparision in the {@link ItemsDataDiffCallback}
+         * @param obj object to compared with
+         * @return true if the same object or has equal value.
+         */
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) {
+                return true;
+            }
+
+            if (!(obj instanceof Item)) {
+                return false;
+            }
+
+            final Item targetItem = (Item) obj;
+            if (type != targetItem.type || id != targetItem.id) {
+                return false;
+            }
+
+            switch (type) {
+                case TYPE_DASHBOARD_CATEGORY:
+                    // Only check title for dashboard category
+                    return TextUtils.equals(((DashboardCategory)entity).title,
+                            ((DashboardCategory) targetItem.entity).title);
+                case TYPE_DASHBOARD_TILE:
+                    final Tile localTile = (Tile)entity;
+                    final Tile targetTile = (Tile)targetItem.entity;
+
+                    // Only check title and summary for dashboard tile
+                    return TextUtils.equals(localTile.title, targetTile.title)
+                            && TextUtils.equals(localTile.summary, targetTile.summary);
+                case TYPE_CONDITION_CARD:
+                    // First check conditionExpanded for quick return
+                    if (conditionExpanded != targetItem.conditionExpanded) {
+                        return false;
+                    }
+                    // After that, go to default to do final check
+                default:
+                    return entity == null ? targetItem.entity == null
+                            : entity.equals(targetItem.entity);
+            }
+        }
+    }
+
+    /**
+     * This class contains the data needed to build the header. The data can also be
+     * used to check the diff in DiffUtil.Callback
+     */
+    public static class SuggestionHeaderData {
+        public final boolean hasMoreSuggestions;
+        public final int suggestionSize;
+        public final int undisplayedSuggestionCount;
+
+        public SuggestionHeaderData(boolean moreSuggestions, int suggestionSize, int
+                undisplayedSuggestionCount) {
+            this.hasMoreSuggestions = moreSuggestions;
+            this.suggestionSize = suggestionSize;
+            this.undisplayedSuggestionCount = undisplayedSuggestionCount;
+        }
+
+        public SuggestionHeaderData() {
+            hasMoreSuggestions = false;
+            suggestionSize = 0;
+            undisplayedSuggestionCount = 0;
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) {
+                return true;
+            }
+
+            if (!(obj instanceof SuggestionHeaderData)) {
+                return false;
+            }
+
+            SuggestionHeaderData targetData = (SuggestionHeaderData) obj;
+
+            return hasMoreSuggestions == targetData.hasMoreSuggestions
+                    && suggestionSize == targetData.suggestionSize
+                    && undisplayedSuggestionCount == targetData.undisplayedSuggestionCount;
+        }
+    }
+
+}

tests/robotests/src/com/android/settings/dashboard/DashboardDataTest.java

@@ -0,0 +1,336 @@
+/*
+ * 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.support.annotation.NonNull;
+import android.support.v7.util.DiffUtil;
+import android.support.v7.util.ListUpdateCallback;
+import com.android.settings.TestConfig;
+import com.android.settings.dashboard.conditional.AirplaneModeCondition;
+import com.android.settings.dashboard.conditional.Condition;
+import com.android.settingslib.drawer.DashboardCategory;
+import com.android.settingslib.drawer.Tile;
+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.annotation.Config;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+@RunWith(RobolectricTestRunner.class)
+@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
+public class DashboardDataTest {
+    private static final String TEST_SUGGESTION_TITLE = "Use fingerprint";
+    private static final String TEST_CATEGORY_TILE_TITLE = "Display";
+
+    private DashboardData mDashboardDataWithOneConditions;
+    private DashboardData mDashboardDataWithTwoConditions;
+    private DashboardData mDashboardDataWithNoItems;
+    @Mock
+    private Tile mTestCategoryTile;
+    @Mock
+    private Tile mTestSuggestion;
+    @Mock
+    private DashboardCategory mDashboardCategory;
+    @Mock
+    private Condition mTestCondition;
+    @Mock
+    private Condition mSecondCondition; // condition used to test insert in DiffUtil
+
+    @Before
+    public void SetUp() {
+        MockitoAnnotations.initMocks(this);
+
+        // Build suggestions
+        final List<Tile> suggestions = new ArrayList<>();
+        mTestSuggestion.title = TEST_SUGGESTION_TITLE;
+        suggestions.add(mTestSuggestion);
+
+        // Build oneItemConditions
+        final List<Condition> oneItemConditions = new ArrayList<>();
+        when(mTestCondition.shouldShow()).thenReturn(true);
+        oneItemConditions.add(mTestCondition);
+
+        // Build twoItemConditions
+        final List<Condition> twoItemsConditions = new ArrayList<>();
+        when(mSecondCondition.shouldShow()).thenReturn(true);
+        twoItemsConditions.add(mTestCondition);
+        twoItemsConditions.add(mSecondCondition);
+
+        // Build categories
+        final List<DashboardCategory> categories = new ArrayList<>();
+        mTestCategoryTile.title = TEST_CATEGORY_TILE_TITLE;
+        mDashboardCategory.title = "test";
+        mDashboardCategory.tiles = new ArrayList<>();
+        mDashboardCategory.tiles.add(mTestCategoryTile);
+        categories.add(mDashboardCategory);
+
+        // Build DashboardData 
+        mDashboardDataWithOneConditions = new DashboardData.Builder()
+                .setConditions(oneItemConditions)
+                .setCategories(categories)
+                .setSuggestions(suggestions)
+                .build();
+
+        mDashboardDataWithTwoConditions = new DashboardData.Builder()
+                .setConditions(twoItemsConditions)
+                .setCategories(categories)
+                .setSuggestions(suggestions)
+                .build();
+
+        mDashboardDataWithNoItems = new DashboardData.Builder()
+                .setConditions(null)
+                .setCategories(null)
+                .setSuggestions(null)
+                .build();
+    }
+
+    @Test
+    public void testBuildItemsData_containsAllData() {
+        final DashboardData.SuggestionHeaderData data =
+                new DashboardData.SuggestionHeaderData(false, 1, 0);
+        final Object[] expectedObjects = {mTestCondition, null, data, mTestSuggestion,
+                mDashboardCategory, mTestCategoryTile};
+        final int expectedSize = expectedObjects.length;
+
+        assertThat(mDashboardDataWithOneConditions.getItemList().size())
+                .isEqualTo(expectedSize);
+        for (int i = 0; i < expectedSize; i++) {
+            if (mDashboardDataWithOneConditions.getItemEntityByPosition(i)
+                    instanceof DashboardData.SuggestionHeaderData) {
+                // SuggestionHeaderData is created inside when build, we can only use isEqualTo
+                assertThat(mDashboardDataWithOneConditions.getItemEntityByPosition(i))
+                        .isEqualTo(expectedObjects[i]);
+            } else {
+                assertThat(mDashboardDataWithOneConditions.getItemEntityByPosition(i))
+                        .isSameAs(expectedObjects[i]);
+            }
+        }
+    }
+
+    @Test
+    public void testGetPositionByEntity_selfInstance_returnPositionFound() {
+        final int position = mDashboardDataWithOneConditions
+                .getPositionByEntity(mTestCondition);
+        assertThat(position).isNotEqualTo(DashboardData.POSITION_NOT_FOUND);
+    }
+
+    @Test
+    public void testGetPositionByEntity_notExisted_returnNotFound() {
+        final Condition condition = mock(AirplaneModeCondition.class);
+        final int position = mDashboardDataWithOneConditions.getPositionByEntity(condition);
+        assertThat(position).isEqualTo(DashboardData.POSITION_NOT_FOUND);
+    }
+
+    @Test
+    public void testGetPositionByTile_selfInstance_returnPositionFound() {
+        final int position = mDashboardDataWithOneConditions
+                .getPositionByTile(mTestCategoryTile);
+        assertThat(position).isNotEqualTo(DashboardData.POSITION_NOT_FOUND);
+    }
+
+    @Test
+    public void testGetPositionByTile_equalTitle_returnPositionFound() {
+        final Tile tile = mock(Tile.class);
+        tile.title = TEST_CATEGORY_TILE_TITLE;
+        final int position = mDashboardDataWithOneConditions.getPositionByTile(tile);
+        assertThat(position).isNotEqualTo(DashboardData.POSITION_NOT_FOUND);
+    }
+
+    @Test
+    public void testGetPositionByTile_notExisted_returnNotFound() {
+        final Tile tile = mock(Tile.class);
+        tile.title = "";
+        final int position = mDashboardDataWithOneConditions.getPositionByTile(tile);
+        assertThat(position).isEqualTo(DashboardData.POSITION_NOT_FOUND);
+    }
+
+    @Test
+    public void testDiffUtil_DataEqual_noResultData() {
+        List<ListUpdateResult.ResultData> testResultData = new ArrayList<>();
+        testDiffUtil(mDashboardDataWithOneConditions, 
+                mDashboardDataWithOneConditions, testResultData);
+    }
+
+    @Test
+    public void testDiffUtil_InsertOneCondition_ResultDataOneInserted() {
+        //Build testResultData
+        final List<ListUpdateResult.ResultData> testResultData = new ArrayList<>();
+        testResultData.add(new ListUpdateResult.ResultData(
+                ListUpdateResult.ResultData.TYPE_OPERATION_INSERT, 1, 1));
+
+        testDiffUtil(mDashboardDataWithOneConditions,
+                mDashboardDataWithTwoConditions, testResultData);
+    }
+
+    @Test
+    public void testDiffUtil_DeleteAllData_ResultDataOneDeleted() {
+        //Build testResultData
+        final List<ListUpdateResult.ResultData> testResultData = new ArrayList<>();
+        testResultData.add(new ListUpdateResult.ResultData(
+                ListUpdateResult.ResultData.TYPE_OPERATION_REMOVE, 0, 6));
+
+        testDiffUtil(mDashboardDataWithOneConditions, mDashboardDataWithNoItems, testResultData);
+    }
+
+    /**
+     * Test when using the
+     * {@link com.android.settings.dashboard.DashboardData.ItemsDataDiffCallback}
+     * to transfer List from {@paramref baseDashboardData} to {@paramref diffDashboardData}, whether
+     * the transform data result is equals to {@paramref testResultData}
+     * <p>
+     * The steps are described below:
+     * 1. Calculate a {@link android.support.v7.util.DiffUtil.DiffResult} from
+     * {@paramref baseDashboardData} to {@paramref diffDashboardData}
+     * <p>
+     * 2. Dispatch the {@link android.support.v7.util.DiffUtil.DiffResult} calculated from step 1
+     * into {@link ListUpdateResult}
+     * <p>
+     * 3. Get result data(a.k.a. baseResultData) from {@link ListUpdateResult} and compare it to
+     * {@paramref testResultData}
+     * <p>
+     * Because baseResultData and {@paramref testResultData} don't have sequence. When do the
+     * comparison, we will sort them first and then compare the inside data from them one by one.
+     *
+     * @param baseDashboardData
+     * @param diffDashboardData
+     * @param testResultData
+     */
+    private void testDiffUtil(DashboardData baseDashboardData, DashboardData diffDashboardData,
+            List<ListUpdateResult.ResultData> testResultData) {
+        final DiffUtil.DiffResult diffUtilResult = DiffUtil.calculateDiff(
+                new DashboardData.ItemsDataDiffCallback(
+                        baseDashboardData.getItemList(), diffDashboardData.getItemList()));
+
+        // Dispatch to listUpdateResult, then listUpdateResult will have result data
+        final ListUpdateResult listUpdateResult = new ListUpdateResult();
+        diffUtilResult.dispatchUpdatesTo(listUpdateResult);
+
+        final List<ListUpdateResult.ResultData> baseResultData = listUpdateResult.getResultData();
+        assertThat(testResultData.size()).isEqualTo(baseResultData.size());
+
+        // Sort them so we can compare them one by one using a for loop
+        Collections.sort(baseResultData);
+        Collections.sort(testResultData);
+        final int size = baseResultData.size();
+        for (int i = 0; i < size; i++) {
+            // Refer to equals method in ResultData
+            assertThat(baseResultData.get(i)).isEqualTo(testResultData.get(i));
+        }
+    }
+
+    /**
+     * This class contains the result about how the changes made to convert one
+     * list to another list. It implements ListUpdateCallback to record the result data.
+     */
+    private static class ListUpdateResult implements ListUpdateCallback {
+        final private List<ResultData> mResultData;
+
+        public ListUpdateResult() {
+            mResultData = new ArrayList<>();
+        }
+
+        public List<ResultData> getResultData() {
+            return mResultData;
+        }
+
+        @Override
+        public void onInserted(int position, int count) {
+            mResultData.add(new ResultData(ResultData.TYPE_OPERATION_INSERT, position, count));
+        }
+
+        @Override
+        public void onRemoved(int position, int count) {
+            mResultData.add(new ResultData(ResultData.TYPE_OPERATION_REMOVE, position, count));
+        }
+
+        @Override
+        public void onMoved(int fromPosition, int toPosition) {
+            mResultData.add(
+                    new ResultData(ResultData.TYPE_OPERATION_MOVE, fromPosition, toPosition));
+        }
+
+        @Override
+        public void onChanged(int position, int count, Object payload) {
+            mResultData.add(new ResultData(ResultData.TYPE_OPERATION_CHANGE, position, count));
+        }
+
+        /**
+         * This class contains general type and field to record the operation data generated
+         * in {@link ListUpdateCallback}. Please refer to {@link ListUpdateCallback} for more info.
+         * <p>
+         * The following are examples about the data stored in this class:
+         * <p>
+         * "The data starts from position(arg1) with count number(arg2) is changed(operation)"
+         * or "The data is moved(operation) from position1(arg1) to position2(arg2)"
+         */
+        private static class ResultData implements Comparable<ResultData> {
+            public static final int TYPE_OPERATION_INSERT = 0;
+            public static final int TYPE_OPERATION_REMOVE = 1;
+            public static final int TYPE_OPERATION_MOVE = 2;
+            public static final int TYPE_OPERATION_CHANGE = 3;
+
+            public final int operation;
+            public final int arg1;
+            public final int arg2;
+
+            public ResultData(int operation, int arg1, int arg2) {
+                this.operation = operation;
+                this.arg1 = arg1;
+                this.arg2 = arg2;
+            }
+
+            @Override
+            public boolean equals(Object obj) {
+                if (this == obj) {
+                    return true;
+                }
+
+                if (!(obj instanceof ResultData)) {
+                    return false;
+                }
+
+                ResultData targetData = (ResultData) obj;
+
+                return operation == targetData.operation && arg1 == targetData.arg1
+                        && arg2 == targetData.arg2;
+            }
+
+            @Override
+            public int compareTo(@NonNull ResultData resultData) {
+                if (this.operation != resultData.operation) {
+                    return operation - resultData.operation;
+                }
+
+                if (arg1 != resultData.arg1) {
+                    return arg1 - resultData.arg1;
+                }
+
+                return arg2 - resultData.arg2;
+            }
+        }
+    }
+}