Android: Dynamically adapt grid span to card_game size

In order to avoid getting stuck making a new dimension file every time a new device is found we take a known value for how large the game card will be, take the screen size, and adjust the grid accordingly.

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/ui/platform/PlatformGamesFragment.java

@@ -6,12 +6,12 @@
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
+import android.view.ViewTreeObserver;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
 import androidx.recyclerview.widget.GridLayoutManager;
-import androidx.recyclerview.widget.RecyclerView;
 import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 
 import com.google.android.material.color.MaterialColors;
@@ -62,11 +62,33 @@ public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
   public void onViewCreated(@NonNull View view, Bundle savedInstanceState)
   {
     mSwipeRefresh = mBinding.swipeRefresh;
-
-    int columns = getResources().getInteger(R.integer.game_grid_columns);
-    RecyclerView.LayoutManager layoutManager = new GridLayoutManager(getActivity(), columns);
     mAdapter = new GameAdapter(requireActivity());
 
+    // Here we have to make sure the fragment is attached to an activity, wait for the layout
+    // to be drawn, and make sure it is drawn with a width > 0 before finding the correct
+    // span for our grid layout. Once drawn correctly, we can stop listening for layout changes.
+    if (isAdded())
+    {
+      view.getViewTreeObserver()
+              .addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener()
+              {
+                @Override
+                public void onGlobalLayout()
+                {
+                  int columns = mBinding.getRoot().getMeasuredWidth() /
+                          requireContext().getResources().getDimensionPixelSize(R.dimen.card_width);
+                  if (columns == 0)
+                  {
+                    columns = 1;
+                  }
+                  view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
+                  GridLayoutManager layoutManager = new GridLayoutManager(getActivity(), columns);
+                  mBinding.gridGames.setLayoutManager(layoutManager);
+                  mBinding.gridGames.setAdapter(mAdapter);
+                }
+              });
+    }
+
     // Set theme color to the refresh animation's background
     mSwipeRefresh.setProgressBackgroundColorSchemeColor(
             MaterialColors.getColor(mSwipeRefresh, R.attr.colorPrimary));
@@ -75,9 +97,6 @@ public void onViewCreated(@NonNull View view, Bundle savedInstanceState)
 
     mSwipeRefresh.setOnRefreshListener(mOnRefreshListener);
 
-    mBinding.gridGames.setLayoutManager(layoutManager);
-    mBinding.gridGames.setAdapter(mAdapter);
-
     InsetsHelper.setUpList(getContext(), mBinding.gridGames);
 
     setRefreshing(GameFileCacheManager.isLoadingOrRescanning());

Source/Android/app/src/main/res/layout/fragment_grid.xml

@@ -7,9 +7,7 @@
     <androidx.swiperefreshlayout.widget.SwipeRefreshLayout
         android:id="@+id/swipe_refresh"
         android:layout_width="wrap_content"
-        android:layout_height="wrap_content"
-        android:layout_marginLeft="@dimen/activity_horizontal_margin"
-        android:layout_marginRight="@dimen/activity_horizontal_margin">
+        android:layout_height="wrap_content">
 
         <androidx.recyclerview.widget.RecyclerView
             android:id="@+id/grid_games"

Source/Android/app/src/main/res/values/dimens.xml

@@ -1,8 +1,6 @@
 <resources>
-    <!-- Default screen margins, per the Android Design guidelines. -->
-    <dimen name="activity_horizontal_margin">16dp</dimen>
-
     <dimen name="spacing_small">4dp</dimen>
     <dimen name="spacing_medlarge">12dp</dimen>
     <dimen name="spacing_large">16dp</dimen>
+    <dimen name="card_width">140dp</dimen>
 </resources>

Source/Android/app/src/main/res/values/integers.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <integer name="game_title_lines">2</integer>
-    <integer name="game_grid_columns">1</integer>
     <integer name="loadsave_state_columns">1</integer>
     <integer name="loadsave_state_rows">6</integer>