Switch to GridLayoutManager to support two-column layout

In order to display both half-width card and full-width card,
we use GridLayoutManager and SpanSizeLookup to achieve this purpose.

Bug: 111822407
Test: manual
Change-Id: I225fb0b5f731e3faf2bca9858395c40d318acf2f

src/com/android/settings/homepage/HomepageAdapter.java

@@ -21,6 +21,7 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import androidx.recyclerview.widget.GridLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 
 import java.util.ArrayList;
@@ -28,14 +29,16 @@ import java.util.List;
 
 public class HomepageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> implements
         HomepageCardUpdateListener {
+    static final int SPAN_COUNT = 2;
 
     private static final String TAG = "HomepageAdapter";
+    private static final int HALF_WIDTH = 1;
+    private static final int FULL_WIDTH = 2;
 
     private final Context mContext;
     private final ControllerRendererPool mControllerRendererPool;
 
     private List<HomepageCard> mHomepageCards;
-    private RecyclerView mRecyclerView;
 
     public HomepageAdapter(Context context, HomepageManager manager) {
         mContext = context;
@@ -81,7 +84,21 @@ public class HomepageAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolde
     @Override
     public void onAttachedToRecyclerView(RecyclerView recyclerView) {
         super.onAttachedToRecyclerView(recyclerView);
-        mRecyclerView = recyclerView;
+        final RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
+        if (layoutManager instanceof GridLayoutManager) {
+            final GridLayoutManager gridLayoutManager = (GridLayoutManager) layoutManager;
+            gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
+                @Override
+                public int getSpanSize(int position) {
+                    final HomepageCard card = mHomepageCards.get(position);
+                    //TODO(b/114009676): may use another field to make decision. still under review.
+                    if (card.isHalfWidth()) {
+                        return HALF_WIDTH;
+                    }
+                    return FULL_WIDTH;
+                }
+            });
+        }
     }
 
     @Override

src/com/android/settings/homepage/PersonalSettingsFragment.java

@@ -16,11 +16,14 @@
 
 package com.android.settings.homepage;
 
+import static com.android.settings.homepage.HomepageAdapter.SPAN_COUNT;
+
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import androidx.recyclerview.widget.GridLayoutManager;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 
@@ -35,7 +38,7 @@ public class PersonalSettingsFragment extends InstrumentedFragment {
     private RecyclerView mCardsContainer;
     //TODO(b/113966426): rename
     private HomepageAdapter mHomepageAdapter;
-    private LinearLayoutManager mLayoutManager;
+    private GridLayoutManager mLayoutManager;
     //TODO(b/113966426): rename
     private HomepageManager mHomepageManager;
 
@@ -52,8 +55,8 @@ public class PersonalSettingsFragment extends InstrumentedFragment {
         final View rootView = inflater.inflate(R.layout.settings_homepage,
                 container, false);
         mCardsContainer = (RecyclerView) rootView.findViewById(R.id.card_container);
-        //TODO(b/111822407): May have to swap to GridLayoutManager
-        mLayoutManager = new LinearLayoutManager(getActivity());
+        mLayoutManager = new GridLayoutManager(getActivity(), SPAN_COUNT,
+                LinearLayoutManager.VERTICAL, false /* reverseLayout */);
         mCardsContainer.setLayoutManager(mLayoutManager);
         mHomepageAdapter = new HomepageAdapter(getContext(), mHomepageManager);
         mCardsContainer.setAdapter(mHomepageAdapter);