Hidden API to control sorting of download manager queries.

This change adds a hidden API to sort download manager queries by size
rather than by time last modified.  This is necessary for the system
download manager UI but, in the interest of keeping the new public API
as minimal as possible for now, I'm leaving @hide on this method.

This change also changes the DownloadManager.COLUMN_ID column to be
identical to BaseColumns._ID, since some code relies on this (such as
CursorAdapter).

Change-Id: Ib89b614d63e988974d4486b122b39365b35b5269

2 files changed, 52 insertions, 5 deletions

diff --git a/api/current.xml b/api/current.xml
index a495d04..1a8953d 100644
--- a/api/current.xml
+++ b/api/current.xml
@@ -96234,7 +96234,7 @@
  type="java.lang.String"
  transient="false"
  volatile="false"
- value=""id""
+ value=""_id""
  static="true"
  final="true"
  deprecated="not deprecated"
diff --git a/core/java/android/net/DownloadManager.java b/core/java/android/net/DownloadManager.java
index cafe0f9..e04367a 100644
--- a/core/java/android/net/DownloadManager.java
+++ b/core/java/android/net/DownloadManager.java
@@ -21,6 +21,7 @@ import android.content.ContentValues;
 import android.database.Cursor;
 import android.database.CursorWrapper;
 import android.os.ParcelFileDescriptor;
+import android.provider.BaseColumns;
 import android.provider.Downloads;
 
 import java.io.File;
@@ -48,7 +49,7 @@ public class DownloadManager {
      * An identifier for a particular download, unique across the system.  Clients use this ID to
      * make subsequent calls related to the download.
      */
-    public final static String COLUMN_ID = "id";
+    public final static String COLUMN_ID = BaseColumns._ID;
 
     /**
      * The client-supplied title for this download.  This will be displayed in system notifications.
@@ -441,8 +442,22 @@ public class DownloadManager {
      * This class may be used to filter download manager queries.
      */
     public static class Query {
-        private Long mId;
+        /**
+         * Constant for use with {@link #orderBy}
+         * @hide
+         */
+        public static final int ORDER_ASCENDING = 1;
+
+        /**
+         * Constant for use with {@link #orderBy}
+         * @hide
+         */
+        public static final int ORDER_DESCENDING = 2;
+
+        private Long mId = null;
         private Integer mStatusFlags = null;
+        private String mOrderByColumn = Downloads.COLUMN_LAST_MODIFICATION;
+        private int mOrderDirection = ORDER_DESCENDING;
 
         /**
          * Include only the download with the given ID.
@@ -464,6 +479,32 @@ public class DownloadManager {
         }
 
         /**
+         * Change the sort order of the returned Cursor.
+         *
+         * @param column one of the COLUMN_* constants; currently, only
+         *         {@link #COLUMN_LAST_MODIFIED_TIMESTAMP} and {@link #COLUMN_TOTAL_SIZE_BYTES} are
+         *         supported.
+         * @param direction either {@link #ORDER_ASCENDING} or {@link #ORDER_DESCENDING}
+         * @return this object
+         * @hide
+         */
+        public Query orderBy(String column, int direction) {
+            if (direction != ORDER_ASCENDING && direction != ORDER_DESCENDING) {
+                throw new IllegalArgumentException("Invalid direction: " + direction);
+            }
+
+            if (column.equals(COLUMN_LAST_MODIFIED_TIMESTAMP)) {
+                mOrderByColumn = Downloads.COLUMN_LAST_MODIFICATION;
+            } else if (column.equals(COLUMN_TOTAL_SIZE_BYTES)) {
+                mOrderByColumn = Downloads.COLUMN_TOTAL_BYTES;
+            } else {
+                throw new IllegalArgumentException("Cannot order by " + column);
+            }
+            mOrderDirection = direction;
+            return this;
+        }
+
+        /**
          * Run this query using the given ContentResolver.
          * @param projection the projection to pass to ContentResolver.query()
          * @return the Cursor returned by ContentResolver.query()
@@ -497,7 +538,10 @@ public class DownloadManager {
                 }
                 selection = joinStrings(" OR ", parts);
             }
-            String orderBy = Downloads.COLUMN_LAST_MODIFICATION + " DESC";
+
+            String orderDirection = (mOrderDirection == ORDER_ASCENDING ? "ASC" : "DESC");
+            String orderBy = mOrderByColumn + " " + orderDirection;
+
             return resolver.query(uri, projection, selection, null, orderBy);
         }
 
@@ -567,6 +611,9 @@ public class DownloadManager {
      */
     public Cursor query(Query query) {
         Cursor underlyingCursor = query.runQuery(mResolver, UNDERLYING_COLUMNS);
+        if (underlyingCursor == null) {
+            return null;
+        }
         return new CursorTranslator(underlyingCursor);
     }
 
@@ -608,7 +655,7 @@ public class DownloadManager {
         public int getColumnIndexOrThrow(String columnName) throws IllegalArgumentException {
             int index = getColumnIndex(columnName);
             if (index == -1) {
-                throw new IllegalArgumentException();
+                throw new IllegalArgumentException("No such column: " + columnName);
             }
             return index;
         }