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Diffstat (limited to 'eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/GlobalCanvasDragInfo.java')
| -rw-r--r-- | eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/GlobalCanvasDragInfo.java | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/GlobalCanvasDragInfo.java b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/GlobalCanvasDragInfo.java new file mode 100644 index 000000000..b918b00bf --- /dev/null +++ b/eclipse/plugins/com.android.ide.eclipse.adt/src/com/android/ide/eclipse/adt/internal/editors/layout/gle2/GlobalCanvasDragInfo.java @@ -0,0 +1,182 @@ +/* + * Copyright (C) 2010 The Android Open Source Project + * + * Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/org/documents/epl-v10.php + * + * 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.ide.eclipse.adt.internal.editors.layout.gle2; + +import com.android.annotations.NonNull; +import com.android.annotations.Nullable; +import com.android.ide.common.api.IViewRule; +import com.android.ide.common.api.Rect; + + +/** + * This singleton is used to keep track of drag'n'drops initiated within this + * session of Eclipse. A drag can be initiated from a palette or from a canvas + * and its content is an Android View fully-qualified class name. + * <p/> + * Overall this is a workaround: the issue is that the drag'n'drop SWT API does not + * allow us to know the transfered data during the initial drag -- only when the + * data is dropped do we know what it is about (and to be more exact there is a workaround + * to do just that which works on Windows but not on Linux/Mac SWT). + * <p/> + * In the GLE we'd like to adjust drag feedback to the data being actually dropped. + * The singleton instance of this class will be used to track the data currently dragged + * off a canvas or its palette and then set back to null when the drag'n'drop is finished. + * <p/> + * Note that when a drag starts in one instance of Eclipse and the dragOver/drop is done + * in a <em>separate</em> instance of Eclipse, the dragged FQCN won't be registered here + * and will be null. + */ +final class GlobalCanvasDragInfo { + + private static final GlobalCanvasDragInfo sInstance = new GlobalCanvasDragInfo(); + + private SimpleElement[] mCurrentElements = null; + private SelectionItem[] mCurrentSelection; + private Object mSourceCanvas = null; + private Runnable mRemoveSourceHandler; + private Rect mDragBounds; + private int mDragBaseline = -1; + + /** Private constructor. Use {@link #getInstance()} to retrieve the singleton. */ + private GlobalCanvasDragInfo() { + // pass + } + + /** Returns the singleton instance. */ + public static GlobalCanvasDragInfo getInstance() { + return sInstance; + } + + /** + * Registers the XML elements being dragged. + * + * @param elements The elements being dragged + * @param primary the "primary" element among the elements; when there is a + * single item dragged this will be the same, but in + * multi-selection it will be the element under the mouse as the + * selection was initiated + * @param selection The selection (which can be null, for example when the + * user drags from the palette) + * @param sourceCanvas An object representing the source we are dragging + * from (used for identity comparisons only) + * @param removeSourceHandler A runnable (or null) which can clean up the + * source. It should only be invoked if the drag operation is a + * move, not a copy. + */ + public void startDrag( + @NonNull SimpleElement[] elements, + @Nullable SelectionItem[] selection, + @Nullable Object sourceCanvas, + @Nullable Runnable removeSourceHandler) { + mCurrentElements = elements; + mCurrentSelection = selection; + mSourceCanvas = sourceCanvas; + mRemoveSourceHandler = removeSourceHandler; + } + + /** Unregisters elements being dragged. */ + public void stopDrag() { + mCurrentElements = null; + mCurrentSelection = null; + mSourceCanvas = null; + mRemoveSourceHandler = null; + mDragBounds = null; + } + + public boolean isDragging() { + return mCurrentElements != null; + } + + /** Returns the elements being dragged. */ + @NonNull + public SimpleElement[] getCurrentElements() { + return mCurrentElements; + } + + /** Returns the selection originally dragged. + * Can be null if the drag did not start in a canvas. + */ + public SelectionItem[] getCurrentSelection() { + return mCurrentSelection; + } + + /** + * Returns the object that call {@link #startDrag(SimpleElement[], SelectionItem[], Object)}. + * Can be null. + * This is not meant to access the object indirectly, it is just meant to compare if the + * source and the destination of the drag'n'drop are the same, so object identity + * is all what matters. + */ + public Object getSourceCanvas() { + return mSourceCanvas; + } + + /** + * Removes source of the drag. This should only be called when the drag and + * drop operation is a move (not a copy). + */ + public void removeSource() { + if (mRemoveSourceHandler != null) { + mRemoveSourceHandler.run(); + mRemoveSourceHandler = null; + } + } + + /** + * Get the bounds of the drag, relative to the starting mouse position. For example, + * if you have a rectangular view of size 100x80, and you start dragging at position + * (15,20) from the top left corner of this rectangle, then the drag bounds would be + * (-15,-20, 100x80). + * <p> + * NOTE: The coordinate units will be in SWT/control pixels, not Android view pixels. + * In other words, they are affected by the canvas zoom: If you zoom the view and the + * bounds of a view grow, the drag bounds will be larger. + * + * @return the drag bounds, or null if there are no bounds for the current drag + */ + public Rect getDragBounds() { + return mDragBounds; + } + + /** + * Set the bounds of the drag, relative to the starting mouse position. See + * {@link #getDragBounds()} for details on the semantics of the drag bounds. + * + * @param dragBounds the new drag bounds, or null if there are no drag bounds + */ + public void setDragBounds(Rect dragBounds) { + mDragBounds = dragBounds; + } + + /** + * Returns the baseline of the drag, or -1 if not applicable + * + * @return the current SWT modifier key mask as an {@link IViewRule} modifier mask + */ + public int getDragBaseline() { + return mDragBaseline; + } + + /** + * Sets the baseline of the drag + * + * @param baseline the new baseline + */ + public void setDragBaseline(int baseline) { + mDragBaseline = baseline; + } +} |