Only run queries for the active tab in the library

src/org/kreed/vanilla/LibraryActivity.java

@@ -58,11 +58,6 @@ import android.widget.Toast;
  * The library activity where songs to play can be selected from the library.
  */
 public class LibraryActivity extends PlaybackActivity implements AdapterView.OnItemClickListener, TextWatcher {
-	/**
-	 * The number of tabs in the song selector.
-	 */
-	private static final int TAB_COUNT = 5;
-
 	private static final int ACTION_PLAY = 0;
 	private static final int ACTION_ENQUEUE = 1;
 	private static final int ACTION_LAST_USED = 2;
@@ -101,7 +96,7 @@ public class LibraryActivity extends PlaybackActivity implements AdapterView.OnI
 		@Override
 		public void onChange(boolean selfChange)
 		{
-			runQuery(mPlaylistAdapter);
+			requestRequery(mPlaylistAdapter);
 		}
 	};
 
@@ -174,9 +169,6 @@ public class LibraryActivity extends PlaybackActivity implements AdapterView.OnI
 
 		if (state != null)
 			mTextFilter.setText(state.getString("filter"));
-
-		// query adapters
-		onMediaChange();
 	}
 
 	@Override
@@ -302,32 +294,37 @@ public class LibraryActivity extends PlaybackActivity implements AdapterView.OnI
 	 */
 	private int setLimiter(MediaAdapter.Limiter limiter)
 	{
+		int tab;
+
 		if (limiter == null) {
 			mAlbumAdapter.setLimiter(null);
 			mSongAdapter.setLimiter(null);
-			return -1;
+			tab = -1;
+		} else {
+			switch (limiter.type) {
+			case MediaUtils.TYPE_ALBUM:
+				mSongAdapter.setLimiter(limiter);
+				requestRequery(mSongAdapter);
+				return 2;
+			case MediaUtils.TYPE_ARTIST:
+				mAlbumAdapter.setLimiter(limiter);
+				mSongAdapter.setLimiter(limiter);
+				tab = 1;
+				break;
+			case MediaUtils.TYPE_GENRE:
+				mSongAdapter.setLimiter(limiter);
+				mAlbumAdapter.setLimiter(null);
+				tab = 2;
+				break;
+			default:
+				throw new IllegalArgumentException("Unsupported limiter type: " + limiter.type);
+			}
 		}
 
-		switch (limiter.type) {
+		requestRequery(mSongAdapter);
-		case MediaUtils.TYPE_ALBUM:
+		requestRequery(mAlbumAdapter);
-			// Clear the cursor so we don't have the old selection showing when
+
-			// we switch to that tab.
+		return tab;
-			mSongAdapter.changeCursor(null);
-			mSongAdapter.setLimiter(limiter);
-			return 2;
-		case MediaUtils.TYPE_ARTIST:
-			mAlbumAdapter.changeCursor(null);
-			mAlbumAdapter.setLimiter(limiter);
-			mSongAdapter.setLimiter(limiter);
-			return 1;
-		case MediaUtils.TYPE_GENRE:
-			mSongAdapter.changeCursor(null);
-			mSongAdapter.setLimiter(limiter);
-			mAlbumAdapter.setLimiter(null);
-			return 2;
-		default:
-			throw new IllegalArgumentException("Unsupported limiter type: " + limiter.type);
-		}
 	}
 
 	public void onItemClick(AdapterView<?> list, View view, int pos, long id)
@@ -351,15 +348,10 @@ public class LibraryActivity extends PlaybackActivity implements AdapterView.OnI
 
 	public void onTextChanged(CharSequence text, int start, int before, int count)
 	{
-		MediaAdapter adapter = mCurrentAdapter;
+		String filter = text.toString();
-		if (adapter != null) {
+		for (MediaAdapter adapter : mAdapters) {
-			String filter = text.toString();
+			adapter.setFilter(filter);
-			adapter.filter(filter);
+			requestRequery(adapter);
-
-			for (int i = TAB_COUNT; --i != -1; ) {
-				if (mAdapters[i] != adapter)
-					mAdapters[i].filter(filter);
-			}
 		}
 	}
 
@@ -751,6 +743,23 @@ public class LibraryActivity extends PlaybackActivity implements AdapterView.OnI
 		return true;
 	}
 
+	/**
+	 * Requery the given adapter. If it is the current adapter, requery
+	 * immediately. Otherwise, mark the adapter as needing a requery and requery
+	 * when its tab is selected.
+	 */
+	public void requestRequery(MediaAdapter adapter)
+	{
+		if (adapter == mCurrentAdapter) {
+			runQuery(adapter);
+		} else {
+			adapter.requestRequery();
+			// Clear the data for non-visible adapters (so we don't show the old
+			// data briefly when we later switch to that adapter)
+			adapter.changeCursor(null);
+		}
+	}
+
 	/**
 	 * Schedule a query to be run for the given adapter on the worker thread.
 	 *
@@ -765,8 +774,8 @@ public class LibraryActivity extends PlaybackActivity implements AdapterView.OnI
 	@Override
 	public void onMediaChange()
 	{
-		for (int i = 0; i != TAB_COUNT; ++i)
+		for (MediaAdapter adapter : mAdapters)
-			runQuery(mAdapters[i]);
+			requestRequery(adapter);
 	}
 
 	private void setSearchBoxVisible(boolean visible)
@@ -811,7 +820,10 @@ public class LibraryActivity extends PlaybackActivity implements AdapterView.OnI
 	 */
 	private void setCurrentTab(int i)
 	{
-		mCurrentAdapter = mAdapters[i];
+		MediaAdapter adapter = mAdapters[i];
+		mCurrentAdapter = adapter;
+		if (adapter.isRequeryNeeded())
+			runQuery(adapter);
 		mTabWidget.setCurrentTab(i);
 		mLists.getChildAt(mCurrentTab).setVisibility(View.GONE);
 		mLists.getChildAt(i).setVisibility(View.VISIBLE);

src/org/kreed/vanilla/MediaAdapter.java

@@ -47,9 +47,9 @@ import java.io.Serializable;
  */
 public class MediaAdapter extends CursorAdapter implements SectionIndexer {
 	/**
-	 * The activity that owns this adapter.
+	 * A context to use.
 	 */
-	private LibraryActivity mActivity;
+	private Context mContext;
 	/**
 	 * The type of media represented by this adapter. Must be one of the
 	 * MediaUtils.FIELD_* constants. Determines which content provider to query for
@@ -106,12 +106,16 @@ public class MediaAdapter extends CursorAdapter implements SectionIndexer {
 	 * The sort order for use with buildSongQuery().
 	 */
 	private String mSongSort;
+	/**
+	 * True if the data is stale and the query should be re-run.
+	 */
+	private boolean mNeedsRequery;
 
 	/**
 	 * Construct a MediaAdapter representing the given <code>type</code> of
 	 * media.
 	 *
-	 * @param activity The activity that owns this adapter.
+	 * @param context A context to use.
 	 * @param type The type of media to represent. Must be one of the
 	 * Song.TYPE_* constants. This determines which content provider to query
 	 * and what fields to display in the views.
@@ -120,16 +124,17 @@ public class MediaAdapter extends CursorAdapter implements SectionIndexer {
 	 * @param hasHeader Wether this view has a header row.
 	 * @param limiter An initial limiter to use
 	 */
-	public MediaAdapter(LibraryActivity activity, int type, boolean expandable, boolean hasHeader, Limiter limiter)
+	public MediaAdapter(Context context, int type, boolean expandable, boolean hasHeader, Limiter limiter)
 	{
-		super(activity, null, false);
+		super(context, null, false);
 
-		mActivity = activity;
+		mContext = context;
 		mType = type;
 		mExpandable = expandable;
 		mHasHeader = hasHeader;
 		mLimiter = limiter;
 		mIndexer = new MusicAlphabetIndexer(1);
+		mNeedsRequery = true;
 
 		switch (type) {
 		case MediaUtils.TYPE_ARTIST:
@@ -215,7 +220,7 @@ public class MediaAdapter extends CursorAdapter implements SectionIndexer {
 			if (pos == 0) {
 				MediaView view;
 				if (convertView == null)
-					view = new MediaView(mActivity, mExpandable);
+					view = new MediaView(mContext, mExpandable);
 				else
 					view = (MediaView)convertView;
 				view.makeHeader(mHeaderText);
@@ -240,16 +245,33 @@ public class MediaAdapter extends CursorAdapter implements SectionIndexer {
 	}
 
 	/**
-	 * Perform filtering on a background thread.
+	 * Returns true if the data is stale and should be requeried.
+	 */
+	public boolean isRequeryNeeded()
+	{
+		return mNeedsRequery;
+	}
+
+	/**
+	 * Mark the current data as requiring a requery.
+	 */
+	public void requestRequery()
+	{
+		mNeedsRequery = true;
+	}
+
+	/**
+	 * Set a new filter.
 	 *
-	 * @param constraint The terms to filter on, separated by spaces. Only
+	 * The data should be requeried after calling this.
+	 *
+	 * @param filter The terms to filter on, separated by spaces. Only
 	 * media that contain all of the terms (in any order) will be displayed
 	 * after filtering is complete.
 	 */
-	public void filter(String constraint)
+	public void setFilter(String filter)
 	{
-		mConstraint = constraint;
+		mConstraint = filter;
-		mActivity.runQuery(this);
 	}
 
 	/**
@@ -334,6 +356,7 @@ public class MediaAdapter extends CursorAdapter implements SectionIndexer {
 	 */
 	public QueryTask buildQuery()
 	{
+		mNeedsRequery = false;
 		return buildQuery(mProjection, false);
 	}
 
@@ -363,16 +386,18 @@ public class MediaAdapter extends CursorAdapter implements SectionIndexer {
 	}
 
 	/**
-	 * Set the limiter for the adapter. A limiter is intended to restrict
+	 * Set the limiter for the adapter.
-	 * displayed media to only those that are children of a given parent
+	 *
-	 * media item.
+	 * A limiter is intended to restrict displayed media to only those that are
+	 * children of a given parent media item.
+	 *
+	 * The data should be requeried after calling this.
 	 *
 	 * @param limiter The limiter, created by {@link MediaAdapter#getLimiter(long)}.
 	 */
 	public final void setLimiter(Limiter limiter)
 	{
 		mLimiter = limiter;
-		mActivity.runQuery(this);
 	}
 
 	/**