Showing recents in search

A list of recent queries will display when search first launches, or
when text query is empty.

Fix: 32452066
Test: make RunSettingsRoboTests
Change-Id: Ic697f8c0795f2315a01406537c7ce1bbf9a813be

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

@@ -0,0 +1,77 @@
+/*
+ * 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.content.Context;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.support.annotation.VisibleForTesting;
+
+import com.android.settings.search.IndexDatabaseHelper;
+import com.android.settings.search.IndexDatabaseHelper.SavedQueriesColumns;
+import com.android.settings.utils.AsyncLoader;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Loader for recently searched queries.
+ */
+public class SavedQueryLoader extends AsyncLoader<List<SearchResult>> {
+
+    // Max number of proposed suggestions
+    @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
+    static final int MAX_PROPOSED_SUGGESTIONS = 5;
+
+    private final SQLiteDatabase mDatabase;
+
+    public SavedQueryLoader(Context context) {
+        super(context);
+        mDatabase = IndexDatabaseHelper.getInstance(context).getReadableDatabase();
+    }
+
+    @Override
+    protected void onDiscardResult(List<SearchResult> result) {
+
+    }
+
+    @Override
+    public List<SearchResult> loadInBackground() {
+        Cursor cursor = mDatabase.query(IndexDatabaseHelper.Tables.TABLE_SAVED_QUERIES /* table */,
+                new String[]{SavedQueriesColumns.QUERY} /* columns */,
+                null /* selection */,
+                null /* selectionArgs */,
+                null /* groupBy */,
+                null /* having */,
+                "rowId DESC" /* orderBy */,
+                String.valueOf(MAX_PROPOSED_SUGGESTIONS) /* limit */);
+        return convertCursorToResult(cursor);
+    }
+
+    private List<SearchResult> convertCursorToResult(Cursor cursor) {
+        final List<SearchResult> results = new ArrayList<>();
+        while (cursor.moveToNext()) {
+            final SavedQueryPayload payload = new SavedQueryPayload(
+                    cursor.getString(cursor.getColumnIndex(SavedQueriesColumns.QUERY)));
+            results.add(new SearchResult.Builder()
+                    .addTitle(payload.query)
+                    .addPayload(payload)
+                    .build());
+        }
+        return results;
+    }
+}