b/2555049 Will only query accounts once when entering Calendars screen

There was noticeable jitter on entering the Calendars screen including
misregistering taps due to the cursor requerying repeatedly during a
sync. This change makes it so we only query on accounts once and then
will requery every five seconds for about a minute. The view will only
be updated if a change has occurred.

Change-Id: I53610836e78d970d452d4c9724a2d3525cd85482

3 files changed, 109 insertions, 90 deletions

diff --git a/src/com/android/calendar/SelectCalendarsActivity.java b/src/com/android/calendar/SelectCalendarsActivity.java
index 74474886..5e46172d 100644
--- a/src/com/android/calendar/SelectCalendarsActivity.java
+++ b/src/com/android/calendar/SelectCalendarsActivity.java
@@ -21,6 +21,7 @@ import android.content.ContentResolver;
 import android.content.Context;
 import android.database.Cursor;
 import android.database.ContentObserver;
+import android.database.MatrixCursor;
 import android.os.Bundle;
 import android.os.Handler;
 import android.provider.Calendar.Calendars;
@@ -41,7 +42,6 @@ public class SelectCalendarsActivity extends ExpandableListActivity
     private Cursor mCursor = null;
     private ExpandableListView mList;
     private SelectCalendarsAdapter mAdapter;
-    private ContentResolver mContentResolver;
     private static final String[] PROJECTION = new String[] {
         Calendars._ID,
         Calendars._SYNC_ACCOUNT_TYPE,
@@ -64,8 +64,9 @@ public class SelectCalendarsActivity extends ExpandableListActivity
                 "1) GROUP BY (_sync_account", //Cheap hack to make WHERE a GROUP BY query
                 null /* selectionArgs */,
                 Calendars._SYNC_ACCOUNT /*sort order*/);
-        mContentResolver = getContentResolver();
-        mAdapter = new SelectCalendarsAdapter(context, mCursor, this);
+        MatrixCursor accountsCursor = Utils.matrixCursorFromCursor(mCursor);
+        startManagingCursor(accountsCursor);
+        mAdapter = new SelectCalendarsAdapter(context, accountsCursor, this);
         mList.setAdapter(mAdapter);
 
         mList.setOnChildClickListener(this);
@@ -79,36 +80,6 @@ public class SelectCalendarsActivity extends ExpandableListActivity
         for(int i = 0; i < count; i++) {
             mList.expandGroup(i);
         }
-
-    }
-
-    // Create an observer so that we can update the views whenever a
-    // Calendar changes.
-    private ContentObserver mObserver = new ContentObserver(new Handler())
-    {
-        @Override
-        public boolean deliverSelfNotifications() {
-            return true;
-        }
-
-        @Override
-        public void onChange(boolean selfChange) {
-            if (!isFinishing()) {
-                mCursor.requery();
-            }
-        }
-    };
-
-    @Override
-    public void onPause() {
-        super.onPause();
-        mContentResolver.unregisterContentObserver(mObserver);
-    }
-
-    @Override
-    protected void onResume() {
-        super.onResume();
-        mContentResolver.registerContentObserver(Calendar.Events.CONTENT_URI, true, mObserver);
     }
 
     @Override
diff --git a/src/com/android/calendar/SelectCalendarsAdapter.java b/src/com/android/calendar/SelectCalendarsAdapter.java
index 47048f54..516cb1e4 100644
--- a/src/com/android/calendar/SelectCalendarsAdapter.java
+++ b/src/com/android/calendar/SelectCalendarsAdapter.java
@@ -48,6 +48,7 @@ public class SelectCalendarsAdapter extends CursorTreeAdapter implements View.On
     private static final String IS_PRIMARY = "\"primary\"";
     private static final String CALENDARS_ORDERBY = IS_PRIMARY + " DESC," + Calendars.DISPLAY_NAME +
             COLLATE_NOCASE;
+    private static final String ACCOUNT_SELECTION = Calendars._SYNC_ACCOUNT + "=?";
 
     // The drawables used for the button to change the visible and sync states on a calendar
     private static final int[] SYNC_VIS_BUTTON_RES = new int[] {
@@ -59,6 +60,7 @@ public class SelectCalendarsAdapter extends CursorTreeAdapter implements View.On
     private final LayoutInflater mInflater;
     private final ContentResolver mResolver;
     private final SelectCalendarsActivity mActivity;
+    private final View mView;
     private Map<String, AuthenticatorDescription> mTypeToAuthDescription
         = new HashMap<String, AuthenticatorDescription>();
     protected AuthenticatorDescription[] mAuthDescs;
@@ -81,6 +83,12 @@ public class SelectCalendarsAdapter extends CursorTreeAdapter implements View.On
     // when a new update comes in, we'd like to leave a token space that won't be canceled.
     private static final int MIN_UPDATE_TOKEN = 1000;
     private static int mUpdateToken = MIN_UPDATE_TOKEN;
+    // How long to wait between requeries of the calendars to see if anything has changed.
+    private static final int REFRESH_DELAY = 5000;
+    // How long to keep refreshing for
+    private static final int REFRESH_DURATION = 60000;
+    private boolean mRefresh = true;
+    private int mNumAccounts;
 
     private static String syncedVisible;
     private static String syncedNotVisible;
@@ -121,22 +129,26 @@ public class SelectCalendarsAdapter extends CursorTreeAdapter implements View.On
                 return;
             }
 
+            // Set up a refresh for some point in the future if we haven't reached our max number
+            // of requeries yet. To make the code to track this easier we just use one count across
+            // all accounts and scale our max by the number of accounts.
+            if(mRefresh) {
+                mView.postDelayed(new RefreshCalendars(token, cookie), REFRESH_DELAY);
+            }
+
             Cursor currentCursor = mChildrenCursors.get(cookie);
             // Check if the new cursor has the same content as our old cursor
             if (currentCursor != null) {
-                if (compareCursors(currentCursor, cursor)) {
+                if (Utils.compareCursors(currentCursor, cursor)) {
                     cursor.close();
                     return;
-                } else {
-                    mActivity.stopManagingCursor(currentCursor);
-                    currentCursor.close();
-                    mChildrenCursors.remove(cookie);
                 }
             }
             // If not then make a new matrix cursor for our Map
-            MatrixCursor newCursor = matrixCursorFromCursor(cursor);
+            MatrixCursor newCursor = Utils.matrixCursorFromCursor(cursor);
+            cursor.close();
             // And update our list of duplicated names
-            Utils.checkForDuplicateNames(mIsDuplicateName, cursor, NAME_COLUMN);
+            Utils.checkForDuplicateNames(mIsDuplicateName, newCursor, NAME_COLUMN);
 
             mChildrenCursors.put((String)cookie, newCursor);
             try {
@@ -145,57 +157,17 @@ public class SelectCalendarsAdapter extends CursorTreeAdapter implements View.On
             } catch (NullPointerException e) {
                 Log.w(TAG, "Adapter expired, try again on the next query: " + e.getMessage());
             }
-            cursor.close();
-        }
-
-        /**
-         * Compares two cursors to see if they contain the same data.
-         *
-         * @return Returns true of the cursors contain the same data and are not null, false
-         * otherwise
-         */
-        private boolean compareCursors(Cursor c1, Cursor c2) {
-            if(c1 == null || c2 == null) {
-                return false;
-            }
-
-            int numColumns = c1.getColumnCount();
-            if (numColumns != c2.getColumnCount()) {
-                return false;
-            }
-
-            if (c1.getCount() != c2.getCount()) {
-                return false;
-            }
-
-            c1.moveToPosition(-1);
-            c2.moveToPosition(-1);
-            while(c1.moveToNext() && c2.moveToNext()) {
-                for(int i = 0; i < numColumns; i++) {
-                    if(!c1.getString(i).equals(c2.getString(i))) {
-                        return false;
-                    }
-                }
-            }
-
-            return true;
-        }
-
-        private MatrixCursor matrixCursorFromCursor(Cursor cursor) {
-            MatrixCursor newCursor = new MatrixCursor(cursor.getColumnNames());
-            int numColumns = cursor.getColumnCount();
-            String data[] = new String[numColumns];
-            cursor.moveToPosition(-1);
-            while (cursor.moveToNext()) {
-                for (int i = 0; i < numColumns; i++) {
-                    data[i] = cursor.getString(i);
-                }
-                newCursor.addRow(data);
+            // Clean up our old cursor if we had one. We have to do this after setting the new
+            // cursor so that our view doesn't throw on an invalid cursor.
+            if (currentCursor != null) {
+                mActivity.stopManagingCursor(currentCursor);
+                currentCursor.close();
             }
-            return newCursor;
         }
     }
 
+
+
     /**
      * Method for changing the sync/vis state when a calendar's button is pressed.
      *
@@ -253,7 +225,9 @@ public class SelectCalendarsAdapter extends CursorTreeAdapter implements View.On
         if (mCalendarsUpdater == null) {
             mCalendarsUpdater = new AsyncCalendarsUpdater(mResolver);
         }
-        if(cursor.getCount() == 0) {
+
+        mNumAccounts = cursor.getCount();
+        if(mNumAccounts == 0) {
             //Should never happen since Calendar requires an account exist to use it.
             Log.e(TAG, "SelectCalendarsAdapter: No accounts were returned!");
         }
@@ -262,6 +236,12 @@ public class SelectCalendarsAdapter extends CursorTreeAdapter implements View.On
         for (int i = 0; i < mAuthDescs.length; i++) {
             mTypeToAuthDescription.put(mAuthDescs[i].type, mAuthDescs[i]);
         }
+        mView = mActivity.getExpandableListView();
+        mView.postDelayed(new Runnable() {
+            public void run() {
+                mRefresh = false;
+            }
+        }, REFRESH_DURATION);
     }
 
     /*
@@ -394,8 +374,8 @@ public class SelectCalendarsAdapter extends CursorTreeAdapter implements View.On
         mCalendarsUpdater.startQuery(groupCursor.getPosition(),
                 account,
                 Calendars.CONTENT_URI, PROJECTION,
-                Calendars._SYNC_ACCOUNT + "=\"" + account + "\"" /*Selection*/,
-                null /* selectionArgs */,
+                ACCOUNT_SELECTION,
+                new String[] { account } /*selectionArgs*/,
                 CALENDARS_ORDERBY);
         return childCursor;
     }
@@ -411,4 +391,24 @@ public class SelectCalendarsAdapter extends CursorTreeAdapter implements View.On
             ViewGroup parent) {
         return mInflater.inflate(R.layout.account_item, parent, false);
     }
+
+    private class RefreshCalendars implements Runnable {
+
+        int mToken;
+        Object mAccount;
+
+        public RefreshCalendars(int token, Object cookie) {
+            mToken = token;
+            mAccount = cookie;
+        }
+
+        public void run() {
+            mCalendarsUpdater.startQuery(mToken,
+                    mAccount,
+                    Calendars.CONTENT_URI, PROJECTION,
+                    ACCOUNT_SELECTION,
+                    new String[] { mAccount.toString() } /*selectionArgs*/,
+                    CALENDARS_ORDERBY);
+        }
+    }
 }
diff --git a/src/com/android/calendar/Utils.java b/src/com/android/calendar/Utils.java
index 8b2660de..adba8214 100644
--- a/src/com/android/calendar/Utils.java
+++ b/src/com/android/calendar/Utils.java
@@ -22,6 +22,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.database.Cursor;
+import android.database.MatrixCursor;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.GradientDrawable;
 import android.net.Uri;
@@ -91,6 +92,53 @@ public class Utils {
         return time;
     }
 
+    public static MatrixCursor matrixCursorFromCursor(Cursor cursor) {
+        MatrixCursor newCursor = new MatrixCursor(cursor.getColumnNames());
+        int numColumns = cursor.getColumnCount();
+        String data[] = new String[numColumns];
+        cursor.moveToPosition(-1);
+        while (cursor.moveToNext()) {
+            for (int i = 0; i < numColumns; i++) {
+                data[i] = cursor.getString(i);
+            }
+            newCursor.addRow(data);
+        }
+        return newCursor;
+    }
+
+    /**
+     * Compares two cursors to see if they contain the same data.
+     *
+     * @return Returns true of the cursors contain the same data and are not null, false
+     * otherwise
+     */
+    public static boolean compareCursors(Cursor c1, Cursor c2) {
+        if(c1 == null || c2 == null) {
+            return false;
+        }
+
+        int numColumns = c1.getColumnCount();
+        if (numColumns != c2.getColumnCount()) {
+            return false;
+        }
+
+        if (c1.getCount() != c2.getCount()) {
+            return false;
+        }
+
+        c1.moveToPosition(-1);
+        c2.moveToPosition(-1);
+        while(c1.moveToNext() && c2.moveToNext()) {
+            for(int i = 0; i < numColumns; i++) {
+                if(!c1.getString(i).equals(c2.getString(i))) {
+                    return false;
+                }
+            }
+        }
+
+        return true;
+    }
+
     /**
      * If the given intent specifies a time (in milliseconds since the epoch),
      * then that time is returned. Otherwise, the current time is returned.