Initial bookmark drag & drop

 Currently can only re-parent (drop into folders, between accounts)
 Has no visual feedback yet either

Change-Id: If02c32a98a836c4567f274f1cb1654a25f469b0f
diff --git a/src/com/android/browser/BookmarkDragHandler.java b/src/com/android/browser/BookmarkDragHandler.java
new file mode 100644
index 0000000..0707058
--- /dev/null
+++ b/src/com/android/browser/BookmarkDragHandler.java
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2011 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.browser;
+
+import android.content.ClipData;
+import android.content.ContentResolver;
+import android.content.ContentUris;
+import android.content.ContentValues;
+import android.content.Context;
+import android.database.Cursor;
+import android.net.Uri;
+import android.provider.BrowserContract;
+import android.provider.BrowserContract.Bookmarks;
+import android.view.DragEvent;
+import android.view.View;
+import android.view.View.OnDragListener;
+
+public class BookmarkDragHandler {
+
+    public static interface BookmarkDragController {
+        boolean startDrag(Cursor item);
+    }
+
+    public static interface BookmarkDragAdapter {
+        void setBookmarkDragHandler(BookmarkDragHandler handler);
+        Cursor getItemForView(View v);
+    }
+
+    static class BookmarkDragState {
+        long id;
+        long parent;
+    }
+
+    static final String BOOKMARK_DRAG_LABEL = "com.android.browser.BOOKMARK_LABEL";
+
+    private Context mContext;
+    private BookmarkDragController mDragController;
+    private BookmarkDragAdapter mDragAdapter;
+
+    public BookmarkDragHandler(Context context, BookmarkDragController controller,
+            BookmarkDragAdapter adapter) {
+        mContext = context;
+        mDragController = controller;
+        mDragAdapter = adapter;
+        mDragAdapter.setBookmarkDragHandler(this);
+    }
+
+    public boolean startDrag(View view, Cursor item, long id) {
+        if (!mDragController.startDrag(item)) {
+            return false;
+        }
+        Uri uri = ContentUris.withAppendedId(
+                BrowserContract.Bookmarks.CONTENT_URI, id);
+        ClipData data = ClipData.newRawUri(BOOKMARK_DRAG_LABEL, uri);
+        BookmarkDragState state = new BookmarkDragState();
+        state.id = id;
+        state.parent = item.getLong(BookmarksLoader.COLUMN_INDEX_PARENT);
+        view.startDrag(data, new View.DragShadowBuilder(view), state, 0);
+        return true;
+    }
+
+    public void registerBookmarkDragHandler(View view) {
+        view.setOnDragListener(mBookmarkDragListener);
+    }
+
+    private OnDragListener mBookmarkDragListener = new OnDragListener() {
+
+        @Override
+        public boolean onDrag(View v, DragEvent event) {
+            Cursor c = mDragAdapter.getItemForView(v);
+            BookmarkDragState state = (BookmarkDragState) event.getLocalState();
+            switch (event.getAction()) {
+            case DragEvent.ACTION_DRAG_STARTED:
+                return true;
+            case DragEvent.ACTION_DROP:
+                long id = c.getLong(BookmarksLoader.COLUMN_INDEX_ID);
+                if (id == state.id) {
+                    // We dropped onto ourselves, show the context menu
+                    v.showContextMenu();
+                    return false;
+                }
+                long parent = c.getLong(BookmarksLoader.COLUMN_INDEX_PARENT);
+                if (isFolder(c)) {
+                    parent = c.getLong(BookmarksLoader.COLUMN_INDEX_ID);
+                }
+                if (parent != state.parent) {
+                    ContentResolver cr = mContext.getContentResolver();
+                    ContentValues values = new ContentValues();
+                    values.put(Bookmarks.PARENT, parent);
+                    Uri uri = event.getClipData().getItemAt(0).getUri();
+                    cr.update(uri, values, null, null);
+                }
+                break;
+            }
+            return false;
+        }
+    };
+
+    static boolean isFolder(Cursor c) {
+        return c.getInt(BookmarksLoader.COLUMN_INDEX_IS_FOLDER) != 0;
+    }
+}