Prevent search crashes from uninstalled apps

All search results are now refreshed when resuming the
search fragment, to prevent crashes from results that
no longer exist.

Change-Id: I905465d14f415598ec7a2ebe7b29ed620cde0962
Fixes: 34817357
Test: make RunSettingsRoboTests
Merged-In: I96a0cbfee711ab9dee49d56bfdc4e885202d9ecd

src/com/android/settings/search2/SearchResultDiffCallback.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2017 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.search2;
+
+import android.support.v7.util.DiffUtil;
+
+import java.util.List;
+
+/**
+ * Callback for DiffUtil to elegantly update search data when the query changes.
+ */
+public class SearchResultDiffCallback extends DiffUtil.Callback {
+
+    private List<SearchResult> mOldList;
+    private List<SearchResult> mNewList;
+
+    public SearchResultDiffCallback(List<SearchResult> oldList, List<SearchResult> newList) {
+        mOldList = oldList;
+        mNewList = newList;
+    }
+
+    @Override
+    public int getOldListSize() {
+        return mOldList.size();
+    }
+
+    @Override
+    public int getNewListSize() {
+        return mNewList.size();
+    }
+
+    @Override
+    public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
+        return mOldList.get(oldItemPosition).equals(mNewList.get(newItemPosition));
+    }
+
+    @Override
+    public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
+        return mOldList.get(oldItemPosition).equals(mNewList.get(newItemPosition));
+    }
+}