2 files changed, 62 insertions, 5 deletions

diff --git a/src/com/android/documentsui/dirlist/AnimationView.java b/src/com/android/documentsui/dirlist/AnimationView.java
index d17bddf98..5813085b3 100644
--- a/src/com/android/documentsui/dirlist/AnimationView.java
+++ b/src/com/android/documentsui/dirlist/AnimationView.java
@@ -16,19 +16,22 @@
 
 package com.android.documentsui.dirlist;
 
-import androidx.annotation.IntDef;
-import androidx.fragment.app.FragmentTransaction;
+import static com.android.documentsui.util.FlagUtils.isUseMaterial3FlagEnabled;
 
 import android.content.Context;
 import android.os.Bundle;
 import android.util.AttributeSet;
 import android.widget.LinearLayout;
 
+import androidx.annotation.IntDef;
+import androidx.fragment.app.FragmentTransaction;
+
 import com.android.documentsui.R;
 import com.android.documentsui.base.Shared;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
+import java.util.ArrayList;
 
 /**
  * This class exists solely to support animated transition of our directory fragment.
@@ -51,6 +54,8 @@ public class AnimationView extends LinearLayout {
     public static final int ANIM_LEAVE = 3;
     public static final int ANIM_ENTER = 4;
 
+    private final ArrayList<OnSizeChangedListener> mOnSizeChangedListeners = new ArrayList<>();
+
     private float mPosition = 0f;
 
     // The distance the animation will cover...currently matches the height of the
@@ -65,11 +70,45 @@ public class AnimationView extends LinearLayout {
         super(context, attrs);
     }
 
+    /**
+     * A listener of the onSizeChanged method.
+     */
+    public interface OnSizeChangedListener {
+        /**
+         * Called on the View's onSizeChanged.
+         */
+        void onSizeChanged();
+    }
+
+    /**
+     * Adds a listener of the onSizeChanged method.
+     */
+    public void addOnSizeChangedListener(OnSizeChangedListener listener) {
+        if (isUseMaterial3FlagEnabled()) {
+            mOnSizeChangedListeners.add(listener);
+        }
+    }
+
+    /**
+     * Removes a listener of the onSizeChanged method.
+     */
+    public void removeOnSizeChangedListener(OnSizeChangedListener listener) {
+        if (isUseMaterial3FlagEnabled()) {
+            mOnSizeChangedListeners.remove(listener);
+        }
+    }
+
+
     @Override
     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
         super.onSizeChanged(w, h, oldw, oldh);
         mSpan = h;
         setPosition(mPosition);
+        if (isUseMaterial3FlagEnabled()) {
+            for (int i = mOnSizeChangedListeners.size() - 1; i >= 0; --i) {
+                mOnSizeChangedListeners.get(i).onSizeChanged();
+            }
+        }
     }
 
     public float getPosition() {
diff --git a/src/com/android/documentsui/dirlist/DirectoryFragment.java b/src/com/android/documentsui/dirlist/DirectoryFragment.java
index 2ea906a60..2911d04e9 100644
--- a/src/com/android/documentsui/dirlist/DirectoryFragment.java
+++ b/src/com/android/documentsui/dirlist/DirectoryFragment.java
@@ -108,6 +108,7 @@ import com.android.documentsui.clipping.ClipStore;
 import com.android.documentsui.clipping.DocumentClipper;
 import com.android.documentsui.clipping.UrisSupplier;
 import com.android.documentsui.dirlist.AnimationView.AnimationType;
+import com.android.documentsui.dirlist.AnimationView.OnSizeChangedListener;
 import com.android.documentsui.picker.PickActivity;
 import com.android.documentsui.services.FileOperation;
 import com.android.documentsui.services.FileOperationService;
@@ -188,7 +189,7 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
     private SelectionMetadata mSelectionMetadata;
     private KeyInputHandler mKeyListener;
     private @Nullable DragHoverListener mDragHoverListener;
-    private View mRootView;
+    private AnimationView mRootView;
     private IconHelper mIconHelper;
     private SwipeRefreshLayout mRefreshLayout;
     private RecyclerView mRecView;
@@ -416,13 +417,27 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
                 || Intent.ACTION_MANAGED_PROFILE_UNAVAILABLE.equals(action);
     }
 
+    private OnSizeChangedListener mOnSizeChangedListener =
+            new AnimationView.OnSizeChangedListener() {
+                @Override
+                public void onSizeChanged() {
+                    if (isUseMaterial3FlagEnabled() && mState.derivedMode != MODE_LIST) {
+                        // Update the grid layout when the window size changes.
+                        updateLayout(mState.derivedMode);
+                    }
+                }
+            };
+
     @Override
     public View onCreateView(
             LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
 
         mHandler = new Handler(Looper.getMainLooper());
         mActivity = (BaseActivity) getActivity();
-        mRootView = inflater.inflate(R.layout.fragment_directory, container, false);
+        mRootView = (AnimationView) inflater.inflate(R.layout.fragment_directory, container, false);
+        if (isUseMaterial3FlagEnabled()) {
+            mRootView.addOnSizeChangedListener(mOnSizeChangedListener);
+        }
 
         mProgressBar = mRootView.findViewById(R.id.progressbar);
         assert mProgressBar != null;
@@ -497,6 +512,10 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         mModel.removeUpdateListener(mAdapter.getModelUpdateListener());
         setPreDrawListenerEnabled(false);
 
+        if (isUseMaterial3FlagEnabled()) {
+            mRootView.removeOnSizeChangedListener(mOnSizeChangedListener);
+        }
+
         super.onDestroyView();
     }
 
@@ -809,7 +828,6 @@ public class DirectoryFragment extends Fragment implements SwipeRefreshLayout.On
         if (mLayout != null) {
             mLayout.setSpanCount(mColumnCount);
         }
-
         int pad = getDirectoryPadding(mode);
         mAppBarHeight = getAppBarLayoutHeight();
         mSaveLayoutHeight = getSaveLayoutHeight();