Add a "Shared with me" section.

MyTracks/src/com/google/android/apps/mytracks/SectionResourceCursorAdapter.java

@@ -0,0 +1,168 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * 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.google.android.apps.mytracks;
+
+import com.google.android.apps.mytracks.content.TracksColumns;
+import com.google.android.maps.mytracks.R;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.database.DataSetObserver;
+import android.support.v4.widget.ResourceCursorAdapter;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.TextView;
+
+/**
+ * A section based resource cursor adapter. Currently only supports one
+ * additional section header, "Shared with me".
+ * 
+ * @author Jimmy Shih
+ */
+public abstract class SectionResourceCursorAdapter extends ResourceCursorAdapter {
+
+  private enum ItemType {
+    TRACK, HEADER
+  }
+
+  private final LayoutInflater layoutInflater;
+  private int sharedWithMeIndex = -1;
+
+  public SectionResourceCursorAdapter(Context context, int layout, Cursor cursor, int flags) {
+    super(context, layout, cursor, flags);
+    this.layoutInflater = LayoutInflater.from(context);
+
+    if (cursor != null) {
+      sharedWithMeIndex = getSharedWithMeIndex();
+      cursor.registerDataSetObserver(dataSetObserver);
+    }
+  }
+
+  private DataSetObserver dataSetObserver = new DataSetObserver() {
+      @Override
+    public void onChanged() {
+      sharedWithMeIndex = getSharedWithMeIndex();
+    };
+
+      @Override
+    public void onInvalidated() {
+      sharedWithMeIndex = -1;
+    };
+  };
+
+  @Override
+  public View getView(int position, View convertView, ViewGroup parent) {
+    if (getItemViewType(position) == ItemType.TRACK.ordinal()) {
+      return super.getView(getCursorPosition(position), convertView, parent);
+    } else {
+      TextView textView;
+      if (convertView == null) {
+        textView = (TextView) layoutInflater.inflate(R.layout.track_list_header, parent, false);
+      } else {
+        textView = (TextView) convertView;
+      }
+      return textView;
+    }
+  }
+
+  @Override
+  public int getViewTypeCount() {
+    return ItemType.values().length;
+  }
+
+  @Override
+  public int getCount() {
+    int count = super.getCount();
+    return count != 0 && sharedWithMeIndex != -1 ? count + 1 : count;
+  }
+
+  @Override
+  public boolean isEnabled(int position) {
+    return getItemViewType(position) == ItemType.TRACK.ordinal();
+  }
+
+  @Override
+  public Object getItem(int position) {
+    if (getItemViewType(position) == ItemType.TRACK.ordinal()) {
+      return super.getItem(getCursorPosition(position));
+    }
+    return null;
+  }
+
+  @Override
+  public long getItemId(int position) {
+    if (getItemViewType(position) == ItemType.TRACK.ordinal()) {
+      return super.getItemId(getCursorPosition(position));
+    }
+    return -1L;
+  }
+
+  @Override
+  public int getItemViewType(int position) {
+    if (sharedWithMeIndex != -1 && sharedWithMeIndex == position) {
+      return ItemType.HEADER.ordinal();
+    }
+    return ItemType.TRACK.ordinal();
+  }
+
+  @Override
+  public Cursor swapCursor(Cursor newCursor) {
+    if (getCursor() != null) {
+      getCursor().unregisterDataSetObserver(dataSetObserver);
+    }
+
+    Cursor oldCursor = super.swapCursor(newCursor);
+    if (newCursor != null) {
+      sharedWithMeIndex = getSharedWithMeIndex();
+      newCursor.registerDataSetObserver(dataSetObserver);
+    }
+    return oldCursor;
+  }
+
+  /**
+   * Gets the Shared with me header index.
+   */
+  private int getSharedWithMeIndex() {
+    int i = 0;
+    Cursor cursor = getCursor();
+    if (cursor != null && cursor.moveToFirst()) {
+      int index = cursor.getColumnIndex(TracksColumns.SHAREDWITHME);
+      do {
+        int sharedWithMe = cursor.getInt(index);
+        if (sharedWithMe == 1) {
+          // Returns the index where sharedWithMe == 1 
+          return i;
+        }
+        i++;
+      } while (cursor.moveToNext());
+    }
+    return -1;
+  }
+
+  /**
+   * Gets the underlying cursor position.
+   * 
+   * @param position the requested position
+   */
+  private int getCursorPosition(int position) {
+    if (sharedWithMeIndex != -1 && position > sharedWithMeIndex) {
+      return position - 1;
+    }
+    return position;
+  }
+}