diff --git a/api/current.txt b/api/current.txt
index 5fd52e3..2b05c3c 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -20301,6 +20301,7 @@
     field public static final java.lang.String FLAGS = "flags";
     field public static final java.lang.String LAST_MODIFIED = "last_modified";
     field public static final java.lang.String MIME_TYPE = "mime_type";
+    field public static final java.lang.String SUMMARY = "summary";
   }
 
   public static abstract interface DocumentsContract.RootColumns {
diff --git a/core/java/android/provider/DocumentsContract.java b/core/java/android/provider/DocumentsContract.java
index 9c2bb49..289531e 100644
--- a/core/java/android/provider/DocumentsContract.java
+++ b/core/java/android/provider/DocumentsContract.java
@@ -267,11 +267,43 @@
          * Type: INTEGER (int)
          */
         public static final String FLAGS = "flags";
+
+        /**
+         * Summary for this document, or {@code null} to omit.
+         * <p>
+         * Type: STRING
+         */
+        public static final String SUMMARY = "summary";
     }
 
+    /**
+     * Root that represents a cloud-based storage service.
+     *
+     * @see RootColumns#ROOT_TYPE
+     */
     public static final int ROOT_TYPE_SERVICE = 1;
+
+    /**
+     * Root that represents a shortcut to content that may be available
+     * elsewhere through another storage root.
+     *
+     * @see RootColumns#ROOT_TYPE
+     */
     public static final int ROOT_TYPE_SHORTCUT = 2;
+
+    /**
+     * Root that represents a physical storage device.
+     *
+     * @see RootColumns#ROOT_TYPE
+     */
     public static final int ROOT_TYPE_DEVICE = 3;
+
+    /**
+     * Root that represents a physical storage device that should only be
+     * displayed to advanced users.
+     *
+     * @see RootColumns#ROOT_TYPE
+     */
     public static final int ROOT_TYPE_DEVICE_ADVANCED = 4;
 
     /**
diff --git a/packages/DocumentsUI/res/layout/activity.xml b/packages/DocumentsUI/res/layout/activity.xml
index d4a01d3..ff28e41 100644
--- a/packages/DocumentsUI/res/layout/activity.xml
+++ b/packages/DocumentsUI/res/layout/activity.xml
@@ -25,20 +25,20 @@
         android:orientation="vertical">
 
         <FrameLayout
-            android:id="@+id/directory"
+            android:id="@+id/container_directory"
             android:layout_width="match_parent"
             android:layout_height="0dip"
             android:layout_weight="1" />
 
         <FrameLayout
-            android:id="@+id/save"
+            android:id="@+id/container_save"
             android:layout_width="match_parent"
             android:layout_height="wrap_content" />
 
     </LinearLayout>
 
-    <ListView
-        android:id="@+id/roots_list"
+    <FrameLayout
+        android:id="@+id/container_roots"
         android:layout_width="250dp"
         android:layout_height="match_parent"
         android:layout_gravity="start"
diff --git a/packages/DocumentsUI/res/layout/fragment_roots.xml b/packages/DocumentsUI/res/layout/fragment_roots.xml
new file mode 100644
index 0000000..d772892
--- /dev/null
+++ b/packages/DocumentsUI/res/layout/fragment_roots.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2013 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.
+-->
+
+<ListView xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@android:id/list"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent" />
diff --git a/packages/DocumentsUI/res/layout/item_root_header.xml b/packages/DocumentsUI/res/layout/item_root_header.xml
new file mode 100644
index 0000000..2b9a46f
--- /dev/null
+++ b/packages/DocumentsUI/res/layout/item_root_header.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2013 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.
+-->
+
+<TextView xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@android:id/title"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:paddingStart="?android:attr/listPreferredItemPaddingStart"
+    android:paddingEnd="?android:attr/listPreferredItemPaddingEnd"
+    android:paddingTop="8dp"
+    android:paddingBottom="8dp"
+    android:singleLine="true"
+    android:ellipsize="marquee"
+    android:textAllCaps="true"
+    android:textAppearance="?android:attr/textAppearanceSmall"
+    android:textAlignment="viewStart" />
diff --git a/packages/DocumentsUI/res/values/strings.xml b/packages/DocumentsUI/res/values/strings.xml
index 3eda207..2ff5d03 100644
--- a/packages/DocumentsUI/res/values/strings.xml
+++ b/packages/DocumentsUI/res/values/strings.xml
@@ -41,4 +41,8 @@
 
     <string name="root_recent">Recent</string>
 
+    <string name="root_type_service">Services</string>
+    <string name="root_type_shortcut">Shortcuts</string>
+    <string name="root_type_device">Devices</string>
+
 </resources>
diff --git a/packages/DocumentsUI/src/com/android/documentsui/CreateDirectoryFragment.java b/packages/DocumentsUI/src/com/android/documentsui/CreateDirectoryFragment.java
new file mode 100644
index 0000000..e19505f
--- /dev/null
+++ b/packages/DocumentsUI/src/com/android/documentsui/CreateDirectoryFragment.java
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2013 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.documentsui;
+
+import android.app.AlertDialog;
+import android.app.Dialog;
+import android.app.DialogFragment;
+import android.app.FragmentManager;
+import android.content.ContentResolver;
+import android.content.ContentValues;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.DialogInterface.OnClickListener;
+import android.net.Uri;
+import android.os.Bundle;
+import android.provider.DocumentsContract;
+import android.provider.DocumentsContract.DocumentColumns;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.widget.EditText;
+import android.widget.Toast;
+
+import com.android.documentsui.model.Document;
+
+/**
+ * Dialog to create a new directory.
+ */
+public class CreateDirectoryFragment extends DialogFragment {
+    private static final String TAG_CREATE_DIRECTORY = "create_directory";
+
+    public static void show(FragmentManager fm) {
+        final CreateDirectoryFragment dialog = new CreateDirectoryFragment();
+        dialog.show(fm, TAG_CREATE_DIRECTORY);
+    }
+
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        final Context context = getActivity();
+        final ContentResolver resolver = context.getContentResolver();
+
+        final AlertDialog.Builder builder = new AlertDialog.Builder(context);
+        final LayoutInflater dialogInflater = LayoutInflater.from(builder.getContext());
+
+        final View view = dialogInflater.inflate(R.layout.dialog_create_dir, null, false);
+        final EditText text1 = (EditText)view.findViewById(android.R.id.text1);
+
+        builder.setTitle(R.string.menu_create_dir);
+        builder.setView(view);
+
+        builder.setPositiveButton(android.R.string.ok, new OnClickListener() {
+            @Override
+            public void onClick(DialogInterface dialog, int which) {
+                final String displayName = text1.getText().toString();
+
+                final ContentValues values = new ContentValues();
+                values.put(DocumentColumns.MIME_TYPE, DocumentsContract.MIME_TYPE_DIRECTORY);
+                values.put(DocumentColumns.DISPLAY_NAME, displayName);
+
+                final DocumentsActivity activity = (DocumentsActivity) getActivity();
+                final Document cwd = activity.getCurrentDirectory();
+
+                final Uri childUri = resolver.insert(cwd.uri, values);
+                if (childUri != null) {
+                    // Navigate into newly created child
+                    final Document childDoc = Document.fromUri(resolver, childUri);
+                    activity.onDocumentPicked(childDoc);
+                } else {
+                    Toast.makeText(context, R.string.save_error, Toast.LENGTH_SHORT).show();
+                }
+            }
+        });
+        builder.setNegativeButton(android.R.string.cancel, null);
+
+        return builder.create();
+    }
+}
diff --git a/packages/DocumentsUI/src/com/android/documentsui/DirectoryFragment.java b/packages/DocumentsUI/src/com/android/documentsui/DirectoryFragment.java
index f6f3f9c..1443f26 100644
--- a/packages/DocumentsUI/src/com/android/documentsui/DirectoryFragment.java
+++ b/packages/DocumentsUI/src/com/android/documentsui/DirectoryFragment.java
@@ -87,13 +87,13 @@
         fragment.setArguments(args);
 
         final FragmentTransaction ft = fm.beginTransaction();
-        ft.replace(R.id.directory, fragment);
+        ft.replace(R.id.container_directory, fragment);
         ft.commitAllowingStateLoss();
     }
 
     public static DirectoryFragment get(FragmentManager fm) {
         // TODO: deal with multiple directories shown at once
-        return (DirectoryFragment) fm.findFragmentById(R.id.directory);
+        return (DirectoryFragment) fm.findFragmentById(R.id.container_directory);
     }
 
     @Override
@@ -360,7 +360,7 @@
                 // TODO: load thumbnails async
                 icon.setImageURI(doc.uri);
             } else {
-                icon.setImageDrawable(DocumentsActivity.resolveDocumentIcon(
+                icon.setImageDrawable(RootsCache.resolveDocumentIcon(
                         context, doc.uri.getAuthority(), doc.mimeType));
             }
 
diff --git a/packages/DocumentsUI/src/com/android/documentsui/DocumentsActivity.java b/packages/DocumentsUI/src/com/android/documentsui/DocumentsActivity.java
index 0cbd1cb..6067581 100644
--- a/packages/DocumentsUI/src/com/android/documentsui/DocumentsActivity.java
+++ b/packages/DocumentsUI/src/com/android/documentsui/DocumentsActivity.java
@@ -19,25 +19,13 @@
 import android.app.ActionBar;
 import android.app.ActionBar.OnNavigationListener;
 import android.app.Activity;
-import android.app.AlertDialog;
-import android.app.Dialog;
-import android.app.DialogFragment;
 import android.app.FragmentManager;
 import android.content.ClipData;
-import android.content.ComponentName;
 import android.content.ContentResolver;
 import android.content.ContentValues;
-import android.content.Context;
-import android.content.DialogInterface;
-import android.content.DialogInterface.OnClickListener;
 import android.content.Intent;
-import android.content.pm.PackageManager;
-import android.content.pm.PackageManager.NameNotFoundException;
-import android.content.pm.ProviderInfo;
-import android.content.pm.ResolveInfo;
 import android.database.Cursor;
 import android.graphics.drawable.ColorDrawable;
-import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.Bundle;
 import android.provider.DocumentsContract;
@@ -47,37 +35,24 @@
 import android.support.v4.widget.DrawerLayout;
 import android.support.v4.widget.DrawerLayout.DrawerListener;
 import android.util.Log;
-import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
-import android.widget.AdapterView;
-import android.widget.AdapterView.OnItemClickListener;
-import android.widget.ArrayAdapter;
 import android.widget.BaseAdapter;
-import android.widget.EditText;
-import android.widget.ImageView;
-import android.widget.ListView;
 import android.widget.SearchView;
 import android.widget.SearchView.OnQueryTextListener;
 import android.widget.TextView;
 import android.widget.Toast;
 
 import com.android.documentsui.model.Document;
-import com.android.documentsui.model.DocumentsProviderInfo;
-import com.android.documentsui.model.DocumentsProviderInfo.Icon;
 import com.android.documentsui.model.Root;
-import com.google.android.collect.Lists;
-import com.google.android.collect.Maps;
 
 import org.json.JSONArray;
 import org.json.JSONException;
 
-import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.List;
 
@@ -86,8 +61,6 @@
 
     // TODO: share backend root cache with recents provider
 
-    private static final String TAG_CREATE_DIRECTORY = "create_directory";
-
     private static final int ACTION_OPEN = 1;
     private static final int ACTION_CREATE = 2;
 
@@ -95,24 +68,12 @@
 
     private SearchView mSearchView;
 
+    private View mRootsContainer;
     private DrawerLayout mDrawerLayout;
     private ActionBarDrawerToggle mDrawerToggle;
 
     private Root mCurrentRoot;
 
-    /** Map from authority to cached info */
-    private static HashMap<String, DocumentsProviderInfo> sProviders = Maps.newHashMap();
-    /** Map from (authority+rootId) to cached info */
-    private static HashMap<Pair<String, String>, Root> sRoots = Maps.newHashMap();
-
-    // TODO: remove once adapter split by type
-    private static ArrayList<Root> sRootsList = Lists.newArrayList();
-
-    private static Root sRecentOpenRoot;
-
-    private RootsAdapter mRootsAdapter;
-    private ListView mRootsList;
-
     private final DisplayState mDisplayState = new DisplayState();
 
     private LinkedList<Document> mStack = new LinkedList<Document>();
@@ -153,11 +114,11 @@
             SaveFragment.show(getFragmentManager(), mimeType, title);
         }
 
+        RootsFragment.show(getFragmentManager());
+
+        mRootsContainer = findViewById(R.id.container_roots);
+
         mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
-        mRootsAdapter = new RootsAdapter(this, sRootsList);
-        mRootsList = (ListView) findViewById(R.id.roots_list);
-        mRootsList.setAdapter(mRootsAdapter);
-        mRootsList.setOnItemClickListener(mRootsListener);
 
         mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
                 R.drawable.ic_drawer, R.string.drawer_open, R.string.drawer_close);
@@ -165,9 +126,7 @@
         mDrawerLayout.setDrawerListener(mDrawerListener);
         mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
 
-        mDrawerLayout.openDrawer(mRootsList);
-
-        updateRoots();
+        mDrawerLayout.openDrawer(mRootsContainer);
 
         // Restore last stack for calling package
         // TODO: move into async loader
@@ -186,7 +145,7 @@
 
         // Start in recents if no restored stack
         if (mStack.isEmpty()) {
-            onRootPicked(sRecentOpenRoot);
+            onRootPicked(RootsCache.getRecentOpenRoot(this), false);
         }
 
         updateDirectoryFragment();
@@ -228,7 +187,7 @@
         actionBar.setDisplayShowHomeEnabled(true);
         actionBar.setDisplayHomeAsUpEnabled(true);
 
-        if (mDrawerLayout.isDrawerOpen(mRootsList)) {
+        if (mDrawerLayout.isDrawerOpen(mRootsContainer)) {
             actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
             actionBar.setIcon(new ColorDrawable());
 
@@ -334,7 +293,7 @@
         if (size > 1) {
             mStack.pop();
             updateDirectoryFragment();
-        } else if (size == 1 && !mDrawerLayout.isDrawerOpen(mRootsList)) {
+        } else if (size == 1 && !mDrawerLayout.isDrawerOpen(mRootsContainer)) {
             // TODO: open root drawer once we can capture back key
             super.onBackPressed();
         } else {
@@ -434,11 +393,15 @@
         dumpStack();
     }
 
-    public void onRootPicked(Root root) {
+    public void onRootPicked(Root root, boolean closeDrawer) {
         // Clear entire backstack and start in new root
         mStack.clear();
         mCurrentRoot = root;
         onDocumentPicked(Document.fromRoot(getContentResolver(), root));
+
+        if (closeDrawer) {
+            mDrawerLayout.closeDrawers();
+        }
     }
 
     public void onDocumentPicked(Document doc) {
@@ -511,7 +474,7 @@
         if (cwd != null) {
             final String authority = cwd.uri.getAuthority();
             final String rootId = DocumentsContract.getRootId(cwd.uri);
-            mCurrentRoot = sRoots.get(Pair.create(authority, rootId));
+            mCurrentRoot = RootsCache.findRoot(this, authority, rootId);
         }
     }
 
@@ -577,172 +540,10 @@
         public static final int SORT_ORDER_DATE = 1;
     }
 
-    public static Drawable resolveDocumentIcon(Context context, String authority, String mimeType) {
-        // Custom icons take precedence
-        final DocumentsProviderInfo info = sProviders.get(authority);
-        if (info != null) {
-            for (Icon icon : info.customIcons) {
-                if (MimePredicate.mimeMatches(icon.mimeType, mimeType)) {
-                    return icon.icon;
-                }
-            }
-        }
-
-        if (DocumentsContract.MIME_TYPE_DIRECTORY.equals(mimeType)) {
-            return context.getResources().getDrawable(R.drawable.ic_dir);
-        } else {
-            final PackageManager pm = context.getPackageManager();
-            final Intent intent = new Intent(Intent.ACTION_VIEW);
-            intent.setType(mimeType);
-
-            final ResolveInfo activityInfo = pm.resolveActivity(
-                    intent, PackageManager.MATCH_DEFAULT_ONLY);
-            if (activityInfo != null) {
-                return activityInfo.loadIcon(pm);
-            } else {
-                return null;
-            }
-        }
-    }
-
-    /**
-     * Gather roots from all known storage providers.
-     */
-    private void updateRoots() {
-        sProviders.clear();
-        sRoots.clear();
-        sRootsList.clear();
-
-        final Context context = this;
-        final PackageManager pm = getPackageManager();
-
-        // Create special roots, like recents
-        {
-            final Root root = Root.buildRecentOpen(context);
-            sRootsList.add(root);
-            sRecentOpenRoot = root;
-        }
-
-        // Query for other storage backends
-        final List<ProviderInfo> providers = pm.queryContentProviders(
-                null, -1, PackageManager.GET_META_DATA);
-        for (ProviderInfo providerInfo : providers) {
-            if (providerInfo.metaData != null && providerInfo.metaData.containsKey(
-                    DocumentsContract.META_DATA_DOCUMENT_PROVIDER)) {
-                final DocumentsProviderInfo info = DocumentsProviderInfo.parseInfo(
-                        this, providerInfo);
-                if (info == null) {
-                    Log.w(TAG, "Missing info for " + providerInfo);
-                    continue;
-                }
-
-                sProviders.put(info.providerInfo.authority, info);
-
-                // TODO: remove deprecated customRoots flag
-                // TODO: populate roots on background thread, and cache results
-                final Uri uri = DocumentsContract.buildRootsUri(providerInfo.authority);
-                final Cursor cursor = getContentResolver().query(uri, null, null, null, null);
-                try {
-                    while (cursor.moveToNext()) {
-                        final Root root = Root.fromCursor(this, info, cursor);
-                        sRoots.put(Pair.create(info.providerInfo.authority, root.rootId), root);
-                        sRootsList.add(root);
-                    }
-                } finally {
-                    cursor.close();
-                }
-            }
-        }
-    }
-
-    private OnItemClickListener mRootsListener = new OnItemClickListener() {
-        @Override
-        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
-            final Root root = mRootsAdapter.getItem(position);
-            onRootPicked(root);
-            mDrawerLayout.closeDrawers();
-        }
-    };
-
     private void dumpStack() {
         Log.d(TAG, "Current stack:");
         for (Document doc : mStack) {
             Log.d(TAG, "--> " + doc);
         }
     }
-
-    public static class RootsAdapter extends ArrayAdapter<Root> {
-        public RootsAdapter(Context context, List<Root> list) {
-            super(context, android.R.layout.simple_list_item_1, list);
-        }
-
-        @Override
-        public View getView(int position, View convertView, ViewGroup parent) {
-            if (convertView == null) {
-                convertView = LayoutInflater.from(parent.getContext())
-                        .inflate(R.layout.item_root, parent, false);
-            }
-
-            final ImageView icon = (ImageView) convertView.findViewById(android.R.id.icon);
-            final TextView title = (TextView) convertView.findViewById(android.R.id.title);
-            final TextView summary = (TextView) convertView.findViewById(android.R.id.summary);
-
-            final Root root = getItem(position);
-            icon.setImageDrawable(root.icon);
-            title.setText(root.title);
-
-            summary.setText(root.summary);
-            summary.setVisibility(root.summary != null ? View.VISIBLE : View.GONE);
-
-            return convertView;
-        }
-    }
-
-    public static class CreateDirectoryFragment extends DialogFragment {
-        public static void show(FragmentManager fm) {
-            final CreateDirectoryFragment dialog = new CreateDirectoryFragment();
-            dialog.show(fm, TAG_CREATE_DIRECTORY);
-        }
-
-        @Override
-        public Dialog onCreateDialog(Bundle savedInstanceState) {
-            final Context context = getActivity();
-            final ContentResolver resolver = context.getContentResolver();
-
-            final AlertDialog.Builder builder = new AlertDialog.Builder(context);
-            final LayoutInflater dialogInflater = LayoutInflater.from(builder.getContext());
-
-            final View view = dialogInflater.inflate(R.layout.dialog_create_dir, null, false);
-            final EditText text1 = (EditText)view.findViewById(android.R.id.text1);
-
-            builder.setTitle(R.string.menu_create_dir);
-            builder.setView(view);
-
-            builder.setPositiveButton(android.R.string.ok, new OnClickListener() {
-                @Override
-                public void onClick(DialogInterface dialog, int which) {
-                    final String displayName = text1.getText().toString();
-
-                    final ContentValues values = new ContentValues();
-                    values.put(DocumentColumns.MIME_TYPE, DocumentsContract.MIME_TYPE_DIRECTORY);
-                    values.put(DocumentColumns.DISPLAY_NAME, displayName);
-
-                    final DocumentsActivity activity = (DocumentsActivity) getActivity();
-                    final Document cwd = activity.getCurrentDirectory();
-
-                    final Uri childUri = resolver.insert(cwd.uri, values);
-                    if (childUri != null) {
-                        // Navigate into newly created child
-                        final Document childDoc = Document.fromUri(resolver, childUri);
-                        activity.onDocumentPicked(childDoc);
-                    } else {
-                        Toast.makeText(context, R.string.save_error, Toast.LENGTH_SHORT).show();
-                    }
-                }
-            });
-            builder.setNegativeButton(android.R.string.cancel, null);
-
-            return builder.create();
-        }
-    }
 }
diff --git a/packages/DocumentsUI/src/com/android/documentsui/RootsCache.java b/packages/DocumentsUI/src/com/android/documentsui/RootsCache.java
new file mode 100644
index 0000000..1b56a20
--- /dev/null
+++ b/packages/DocumentsUI/src/com/android/documentsui/RootsCache.java
@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) 2013 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.documentsui;
+
+import static com.android.documentsui.DocumentsActivity.TAG;
+
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.content.pm.ProviderInfo;
+import android.content.pm.ResolveInfo;
+import android.database.Cursor;
+import android.graphics.drawable.Drawable;
+import android.net.Uri;
+import android.provider.DocumentsContract;
+import android.util.Log;
+import android.util.Pair;
+
+import com.android.documentsui.model.DocumentsProviderInfo;
+import com.android.documentsui.model.DocumentsProviderInfo.Icon;
+import com.android.documentsui.model.Root;
+import com.android.internal.annotations.GuardedBy;
+import com.google.android.collect.Lists;
+import com.google.android.collect.Maps;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+
+/**
+ * Cache of known storage backends and their roots.
+ */
+public class RootsCache {
+
+    // TODO: cache roots in local provider to avoid spinning up backends
+
+    private static boolean sCached = false;
+
+    /** Map from authority to cached info */
+    private static HashMap<String, DocumentsProviderInfo> sProviders = Maps.newHashMap();
+    /** Map from (authority+rootId) to cached info */
+    private static HashMap<Pair<String, String>, Root> sRoots = Maps.newHashMap();
+
+    public static ArrayList<Root> sRootsList = Lists.newArrayList();
+
+    private static Root sRecentOpenRoot;
+
+    /**
+     * Gather roots from all known storage providers.
+     */
+    private static void ensureCache(Context context) {
+        if (sCached) return;
+        sCached = true;
+
+        sProviders.clear();
+        sRoots.clear();
+        sRootsList.clear();
+
+        {
+            // Create special root for recents
+            final Root root = Root.buildRecentOpen(context);
+            sRootsList.add(root);
+            sRecentOpenRoot = root;
+        }
+
+        // Query for other storage backends
+        final PackageManager pm = context.getPackageManager();
+        final List<ProviderInfo> providers = pm.queryContentProviders(
+                null, -1, PackageManager.GET_META_DATA);
+        for (ProviderInfo providerInfo : providers) {
+            if (providerInfo.metaData != null && providerInfo.metaData.containsKey(
+                    DocumentsContract.META_DATA_DOCUMENT_PROVIDER)) {
+                final DocumentsProviderInfo info = DocumentsProviderInfo.parseInfo(
+                        context, providerInfo);
+                if (info == null) {
+                    Log.w(TAG, "Missing info for " + providerInfo);
+                    continue;
+                }
+
+                sProviders.put(info.providerInfo.authority, info);
+
+                // TODO: remove deprecated customRoots flag
+                // TODO: populate roots on background thread, and cache results
+                final Uri uri = DocumentsContract.buildRootsUri(providerInfo.authority);
+                final Cursor cursor = context.getContentResolver()
+                        .query(uri, null, null, null, null);
+                try {
+                    while (cursor.moveToNext()) {
+                        final Root root = Root.fromCursor(context, info, cursor);
+                        sRoots.put(Pair.create(info.providerInfo.authority, root.rootId), root);
+                        sRootsList.add(root);
+                    }
+                } finally {
+                    cursor.close();
+                }
+            }
+        }
+    }
+
+    @GuardedBy("ActivityThread")
+    public static DocumentsProviderInfo findProvider(Context context, String authority) {
+        ensureCache(context);
+        return sProviders.get(authority);
+    }
+
+    @GuardedBy("ActivityThread")
+    public static Root findRoot(Context context, String authority, String rootId) {
+        ensureCache(context);
+        return sRoots.get(Pair.create(authority, rootId));
+    }
+
+    @GuardedBy("ActivityThread")
+    public static Root getRecentOpenRoot(Context context) {
+        ensureCache(context);
+        return sRecentOpenRoot;
+    }
+
+    @GuardedBy("ActivityThread")
+    public static Collection<Root> getRoots() {
+        return sRootsList;
+    }
+
+    @GuardedBy("ActivityThread")
+    public static Drawable resolveDocumentIcon(Context context, String authority, String mimeType) {
+        // Custom icons take precedence
+        ensureCache(context);
+        final DocumentsProviderInfo info = sProviders.get(authority);
+        if (info != null) {
+            for (Icon icon : info.customIcons) {
+                if (MimePredicate.mimeMatches(icon.mimeType, mimeType)) {
+                    return icon.icon;
+                }
+            }
+        }
+
+        if (DocumentsContract.MIME_TYPE_DIRECTORY.equals(mimeType)) {
+            return context.getResources().getDrawable(R.drawable.ic_dir);
+        } else {
+            final PackageManager pm = context.getPackageManager();
+            final Intent intent = new Intent(Intent.ACTION_VIEW);
+            intent.setType(mimeType);
+
+            final ResolveInfo activityInfo = pm.resolveActivity(
+                    intent, PackageManager.MATCH_DEFAULT_ONLY);
+            if (activityInfo != null) {
+                return activityInfo.loadIcon(pm);
+            } else {
+                return null;
+            }
+        }
+    }
+}
diff --git a/packages/DocumentsUI/src/com/android/documentsui/RootsFragment.java b/packages/DocumentsUI/src/com/android/documentsui/RootsFragment.java
new file mode 100644
index 0000000..3e645bc
--- /dev/null
+++ b/packages/DocumentsUI/src/com/android/documentsui/RootsFragment.java
@@ -0,0 +1,186 @@
+/*
+ * Copyright (C) 2013 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.documentsui;
+
+import static com.android.documentsui.DocumentsActivity.TAG;
+
+import android.app.Fragment;
+import android.app.FragmentManager;
+import android.app.FragmentTransaction;
+import android.content.Context;
+import android.os.Bundle;
+import android.provider.DocumentsContract;
+import android.util.Log;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.AdapterView;
+import android.widget.AdapterView.OnItemClickListener;
+import android.widget.ArrayAdapter;
+import android.widget.ImageView;
+import android.widget.ListView;
+import android.widget.TextView;
+
+import com.android.documentsui.SectionedListAdapter.SectionAdapter;
+import com.android.documentsui.model.Root;
+import com.android.documentsui.model.Root.RootComparator;
+
+import java.util.Collection;
+
+/**
+ * Display list of known storage backend roots.
+ */
+public class RootsFragment extends Fragment {
+
+    private ListView mList;
+    private SectionedRootsAdapter mAdapter;
+
+    public static void show(FragmentManager fm) {
+        final RootsFragment fragment = new RootsFragment();
+
+        final FragmentTransaction ft = fm.beginTransaction();
+        ft.replace(R.id.container_roots, fragment);
+        ft.commitAllowingStateLoss();
+    }
+
+    public static RootsFragment get(FragmentManager fm) {
+        return (RootsFragment) fm.findFragmentById(R.id.container_roots);
+    }
+
+    @Override
+    public View onCreateView(
+            LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+        final Context context = inflater.getContext();
+
+        final View view = inflater.inflate(R.layout.fragment_roots, container, false);
+        mList = (ListView) view.findViewById(android.R.id.list);
+
+        mAdapter = new SectionedRootsAdapter(context, RootsCache.getRoots());
+        mList.setAdapter(mAdapter);
+        mList.setOnItemClickListener(mItemListener);
+
+        return view;
+    }
+
+    private OnItemClickListener mItemListener = new OnItemClickListener() {
+        @Override
+        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
+            final Root root = (Root) mAdapter.getItem(position);
+            ((DocumentsActivity) getActivity()).onRootPicked(root, true);
+        }
+    };
+
+    public static class RootsAdapter extends ArrayAdapter<Root> implements SectionAdapter {
+        private int mHeaderId;
+
+        public RootsAdapter(Context context, int headerId) {
+            super(context, 0);
+            mHeaderId = headerId;
+        }
+
+        @Override
+        public View getView(int position, View convertView, ViewGroup parent) {
+            if (convertView == null) {
+                convertView = LayoutInflater.from(parent.getContext())
+                        .inflate(R.layout.item_root, parent, false);
+            }
+
+            final ImageView icon = (ImageView) convertView.findViewById(android.R.id.icon);
+            final TextView title = (TextView) convertView.findViewById(android.R.id.title);
+            final TextView summary = (TextView) convertView.findViewById(android.R.id.summary);
+
+            final Root root = getItem(position);
+            icon.setImageDrawable(root.icon);
+            title.setText(root.title);
+
+            summary.setText(root.summary);
+            summary.setVisibility(root.summary != null ? View.VISIBLE : View.GONE);
+
+            return convertView;
+        }
+
+        @Override
+        public View getHeaderView(View convertView, ViewGroup parent) {
+            if (convertView == null) {
+                convertView = LayoutInflater.from(parent.getContext())
+                        .inflate(R.layout.item_root_header, parent, false);
+            }
+
+            final TextView title = (TextView) convertView.findViewById(android.R.id.title);
+            title.setText(mHeaderId);
+
+            return convertView;
+        }
+    }
+
+    public static class SectionedRootsAdapter extends SectionedListAdapter {
+        private final RootsAdapter mServices;
+        private final RootsAdapter mShortcuts;
+        private final RootsAdapter mDevices;
+        private final RootsAdapter mDevicesAdvanced;
+
+        public SectionedRootsAdapter(Context context, Collection<Root> roots) {
+            mServices = new RootsAdapter(context, R.string.root_type_service);
+            mShortcuts = new RootsAdapter(context, R.string.root_type_shortcut);
+            mDevices = new RootsAdapter(context, R.string.root_type_device);
+            mDevicesAdvanced = new RootsAdapter(context, R.string.root_type_device);
+
+            for (Root root : roots) {
+                Log.d(TAG, "Found rootType=" + root.rootType);
+                switch (root.rootType) {
+                    case DocumentsContract.ROOT_TYPE_SERVICE:
+                        mServices.add(root);
+                        break;
+                    case DocumentsContract.ROOT_TYPE_SHORTCUT:
+                        mShortcuts.add(root);
+                        break;
+                    case DocumentsContract.ROOT_TYPE_DEVICE:
+                        mDevices.add(root);
+                        mDevicesAdvanced.add(root);
+                        break;
+                    case DocumentsContract.ROOT_TYPE_DEVICE_ADVANCED:
+                        mDevicesAdvanced.add(root);
+                        break;
+                }
+            }
+
+            final RootComparator comp = new RootComparator();
+            mServices.sort(comp);
+            mShortcuts.sort(comp);
+            mDevices.sort(comp);
+            mDevicesAdvanced.sort(comp);
+
+            // TODO: switch to hide advanced items by default
+            setShowAdvanced(true);
+        }
+
+        public void setShowAdvanced(boolean showAdvanced) {
+            clearSections();
+            if (mServices.getCount() > 0) {
+                addSection(mServices);
+            }
+            if (mShortcuts.getCount() > 0) {
+                addSection(mShortcuts);
+            }
+
+            final RootsAdapter devices = showAdvanced ? mDevicesAdvanced : mDevices;
+            if (devices.getCount() > 0) {
+                addSection(devices);
+            }
+        }
+    }
+}
diff --git a/packages/DocumentsUI/src/com/android/documentsui/SaveFragment.java b/packages/DocumentsUI/src/com/android/documentsui/SaveFragment.java
index cdc399d..304f6e3 100644
--- a/packages/DocumentsUI/src/com/android/documentsui/SaveFragment.java
+++ b/packages/DocumentsUI/src/com/android/documentsui/SaveFragment.java
@@ -49,7 +49,7 @@
         fragment.setArguments(args);
 
         final FragmentTransaction ft = fm.beginTransaction();
-        ft.replace(R.id.save, fragment, TAG);
+        ft.replace(R.id.container_save, fragment, TAG);
         ft.commitAllowingStateLoss();
     }
 
@@ -65,7 +65,7 @@
         final View view = inflater.inflate(R.layout.fragment_save, container, false);
 
         final ImageView icon = (ImageView) view.findViewById(android.R.id.icon);
-        icon.setImageDrawable(DocumentsActivity.resolveDocumentIcon(
+        icon.setImageDrawable(RootsCache.resolveDocumentIcon(
                 context, null, getArguments().getString(EXTRA_MIME_TYPE)));
 
         mDisplayName = (EditText) view.findViewById(android.R.id.title);
diff --git a/packages/DocumentsUI/src/com/android/documentsui/SectionedListAdapter.java b/packages/DocumentsUI/src/com/android/documentsui/SectionedListAdapter.java
new file mode 100644
index 0000000..aacce65
--- /dev/null
+++ b/packages/DocumentsUI/src/com/android/documentsui/SectionedListAdapter.java
@@ -0,0 +1,160 @@
+/*
+ * Copyright (C) 2013 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.documentsui;
+
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.BaseAdapter;
+import android.widget.ListAdapter;
+
+import com.google.android.collect.Lists;
+
+import java.util.ArrayList;
+
+/**
+ * Adapter that combines multiple adapters as sections, asking each section to
+ * provide a header, and correctly handling item types across child adapters.
+ */
+public class SectionedListAdapter extends BaseAdapter {
+    private ArrayList<SectionAdapter> mSections = Lists.newArrayList();
+
+    public interface SectionAdapter extends ListAdapter {
+        public View getHeaderView(View convertView, ViewGroup parent);
+    }
+
+    public void clearSections() {
+        mSections.clear();
+        notifyDataSetChanged();
+    }
+
+    public void addSection(SectionAdapter adapter) {
+        mSections.add(adapter);
+        notifyDataSetChanged();
+    }
+
+    @Override
+    public int getCount() {
+        int count = 0;
+        final int size = mSections.size();
+        for (int i = 0; i < size; i++) {
+            count += mSections.get(i).getCount() + 1;
+        }
+        return count;
+    }
+
+    @Override
+    public Object getItem(int position) {
+        final int size = mSections.size();
+        for (int i = 0; i < size; i++) {
+            final SectionAdapter section = mSections.get(i);
+            final int sectionSize = section.getCount() + 1;
+
+            // Check if position inside this section
+            if (position == 0) {
+                return section;
+            } else if (position < sectionSize) {
+                return section.getItem(position - 1);
+            }
+
+            // Otherwise jump into next section
+            position -= sectionSize;
+        }
+        throw new IllegalStateException("Unknown position " + position);
+    }
+
+    @Override
+    public long getItemId(int position) {
+        return position;
+    }
+
+    @Override
+    public View getView(int position, View convertView, ViewGroup parent) {
+        final int size = mSections.size();
+        for (int i = 0; i < size; i++) {
+            final SectionAdapter section = mSections.get(i);
+            final int sectionSize = section.getCount() + 1;
+
+            // Check if position inside this section
+            if (position == 0) {
+                return section.getHeaderView(convertView, parent);
+            } else if (position < sectionSize) {
+                return section.getView(position - 1, convertView, parent);
+            }
+
+            // Otherwise jump into next section
+            position -= sectionSize;
+        }
+        throw new IllegalStateException("Unknown position " + position);
+    }
+
+    @Override
+    public boolean areAllItemsEnabled() {
+        return false;
+    }
+
+    @Override
+    public boolean isEnabled(int position) {
+        final int size = mSections.size();
+        for (int i = 0; i < size; i++) {
+            final SectionAdapter section = mSections.get(i);
+            final int sectionSize = section.getCount() + 1;
+
+            // Check if position inside this section
+            if (position == 0) {
+                return false;
+            } else if (position < sectionSize) {
+                return section.isEnabled(position);
+            }
+
+            // Otherwise jump into next section
+            position -= sectionSize;
+        }
+        throw new IllegalStateException("Unknown position " + position);
+    }
+
+    @Override
+    public int getItemViewType(int position) {
+        int type = 1;
+        final int size = mSections.size();
+        for (int i = 0; i < size; i++) {
+            final SectionAdapter section = mSections.get(i);
+            final int sectionSize = section.getCount() + 1;
+
+            // Check if position inside this section
+            if (position == 0) {
+                return 0;
+            } else if (position < sectionSize) {
+                return type + section.getItemViewType(position - 1);
+            }
+
+            // Otherwise jump into next section
+            position -= sectionSize;
+            type += section.getViewTypeCount();
+        }
+        throw new IllegalStateException("Unknown position " + position);
+    }
+
+    @Override
+    public int getViewTypeCount() {
+        int count = 1;
+        final int size = mSections.size();
+        for (int i = 0; i < size; i++) {
+            count += mSections.get(i).getViewTypeCount();
+        }
+        return count;
+    }
+}
diff --git a/packages/DocumentsUI/src/com/android/documentsui/model/Document.java b/packages/DocumentsUI/src/com/android/documentsui/model/Document.java
index 94b9093..ed69690 100644
--- a/packages/DocumentsUI/src/com/android/documentsui/model/Document.java
+++ b/packages/DocumentsUI/src/com/android/documentsui/model/Document.java
@@ -155,7 +155,7 @@
             if (leftDir != rightDir) {
                 return leftDir ? -1 : 1;
             } else {
-                return lhs.displayName.compareToIgnoreCase(rhs.displayName);
+                return Root.compareToIgnoreCaseNullable(lhs.displayName, rhs.displayName);
             }
         }
     }
diff --git a/packages/DocumentsUI/src/com/android/documentsui/model/Root.java b/packages/DocumentsUI/src/com/android/documentsui/model/Root.java
index ef3b8d7..9d816d7 100644
--- a/packages/DocumentsUI/src/com/android/documentsui/model/Root.java
+++ b/packages/DocumentsUI/src/com/android/documentsui/model/Root.java
@@ -29,6 +29,8 @@
 import com.android.documentsui.R;
 import com.android.documentsui.RecentsProvider;
 
+import java.util.Comparator;
+
 /**
  * Representation of a root under a storage backend.
  */
@@ -89,4 +91,22 @@
 
         return root;
     }
+
+    public static class RootComparator implements Comparator<Root> {
+        @Override
+        public int compare(Root lhs, Root rhs) {
+            final int score = compareToIgnoreCaseNullable(lhs.title, rhs.title);
+            if (score != 0) {
+                return score;
+            } else {
+                return compareToIgnoreCaseNullable(lhs.summary, rhs.summary);
+            }
+        }
+    }
+
+    public static int compareToIgnoreCaseNullable(String lhs, String rhs) {
+        if (lhs == null) return -1;
+        if (rhs == null) return 1;
+        return lhs.compareToIgnoreCase(rhs);
+    }
 }