/*
* Copyright 2008 Fred Sauer
*
* 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.allen_sauer.gwt.dnd.client;
import com.google.gwt.user.client.Command;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.DeferredCommand;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.ui.FocusPanel;
import com.google.gwt.user.client.ui.MouseListener;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.SourcesMouseEvents;
import com.google.gwt.user.client.ui.Widget;
import com.allen_sauer.gwt.dnd.client.util.DOMUtil;
import com.allen_sauer.gwt.dnd.client.util.Location;
import com.allen_sauer.gwt.dnd.client.util.WidgetLocation;
import java.util.HashMap;
/**
* Implementation helper class which handles mouse events for all
* draggable widgets for a given {@link DragController}.
*/
class MouseDragHandler implements MouseListener {
private static final int ACTIVELY_DRAGGING = 3;
private static final int DRAGGING_NO_MOVEMENT_YET = 2;
private static final int NOT_DRAGGING = 1;
private FocusPanel capturingWidget;
private final DragContext context;
private DeferredMoveCommand deferredMoveCommand = new DeferredMoveCommand(this);
private int dragging = NOT_DRAGGING;
private HashMap<Widget, Widget> dragHandleMap = new HashMap<Widget, Widget>();
private boolean mouseDown;
private int mouseDownOffsetX;
private int mouseDownOffsetY;
private Widget mouseDownWidget;
MouseDragHandler(DragContext context) {
this.context = context;
initCapturingWidget();
}
public void onMouseDown(Widget sender, int x, int y) {
if (dragging == ACTIVELY_DRAGGING || dragging == DRAGGING_NO_MOVEMENT_YET) {
// Ignore additional mouse buttons depressed while still dragging
return;
}
Event event = DOM.eventGetCurrentEvent();
int button = DOM.eventGetButton(event);
if (button != Event.BUTTON_LEFT) {
return;
}
// mouse down (not first mouse move) determines draggable widget
mouseDownWidget = sender;
context.draggable = dragHandleMap.get(mouseDownWidget);
assert context.draggable != null;
if (!toggleKey(event) && !context.selectedWidgets.contains(mouseDownWidget)) {
context.dragController.clearSelection();
context.dragController.toggleSelection(context.draggable);
}
if (context.dragController.getBehaviorCancelDocumentSelections()) {
DeferredCommand.addCommand(new Command() {
public void execute() {
DOMUtil.cancelAllDocumentSelections();
}
});
}
mouseDown = true;
DOM.eventPreventDefault(event);
mouseDownOffsetX = x;
mouseDownOffsetY = y;
WidgetLocation loc1 = new WidgetLocation(mouseDownWidget, null);
if (mouseDownWidget != context.draggable) {
WidgetLocation loc2 = new WidgetLocation(context.draggable, null);
mouseDownOffsetX += loc1.getLeft() - loc2.getLeft();
mouseDownOffsetY += loc1.getTop() - loc2.getTop();
}
if (context.dragController.getBehaviorDragStartSensitivity() == 0 && !toggleKey(event)) {
// set context.mouseX/Y before startDragging() is called
context.mouseX = x + loc1.getLeft();
context.mouseY = y + loc1.getTop();
startDragging();
if (dragging == NOT_DRAGGING) {
return;
}
actualMove(context.mouseX, context.mouseY);
}
}
public void onMouseEnter(Widget sender) {
}
public void onMouseLeave(Widget sender) {
if (mouseDown && dragging == NOT_DRAGGING) {
// TODO DOMUtil.cancelAllDocumentSelections(); ?
startDragging();
}
}
public void onMouseMove(Widget sender, int x, int y) {
if (dragging == ACTIVELY_DRAGGING || dragging == DRAGGING_NO_MOVEMENT_YET) {
// TODO remove Safari workaround after GWT issue 1807 fixed
if (sender != capturingWidget) {
// In Safari 1.3.2 MAC, other mouse events continue to arrive even when capturing
return;
}
dragging = ACTIVELY_DRAGGING;
} else {
if (mouseDown) {
if (Math.max(Math.abs(x - mouseDownOffsetX), Math.abs(y - mouseDownOffsetY)) >= context.dragController.getBehaviorDragStartSensitivity()) {
if (context.dragController.getBehaviorCancelDocumentSelections()) {
DOMUtil.cancelAllDocumentSelections();
}
if (!context.selectedWidgets.contains(context.draggable)) {
context.dragController.toggleSelection(context.draggable);
}
startDragging();
// adjust (x,y) to be relative to capturingWidget at (0,0)
Location location = new WidgetLocation(mouseDownWidget, null);
x += location.getLeft();
y += location.getTop();
} else {
// prevent IE image drag when drag sensitivity > 5
DOM.eventPreventDefault(DOM.eventGetCurrentEvent());
}
}
if (dragging == NOT_DRAGGING) {
return;
}
}
// proceed with the actual drag
DOM.eventPreventDefault(DOM.eventGetCurrentEvent());
deferredMoveCommand.scheduleOrExecute(x, y);
}
public void onMouseUp(Widget sender, int x, int y) {
Event event = DOM.eventGetCurrentEvent();
int button = DOM.eventGetButton(event);
if (button != Event.BUTTON_LEFT) {
return;
}
mouseDown = false;
// in case mouse down occurred elsewhere
if (mouseDownWidget == null) {
return;
}
if (context.dragController.getBehaviorCancelDocumentSelections()) {
DOMUtil.cancelAllDocumentSelections();
}
if (dragging == NOT_DRAGGING) {
doSelectionToggle(event);
return;
}
// TODO Remove Safari workaround after GWT issue 1807 fixed
if (sender != capturingWidget) {
// In Safari 1.3.2 MAC does not honor capturing widget for mouse up
Location location = new WidgetLocation(sender, null);
x += location.getLeft();
y += location.getTop();
}
// Proceed with the drop
try {
drop(x, y);
if (dragging != ACTIVELY_DRAGGING) {
doSelectionToggle(event);
}
} finally {
dragEndCleanup();
}
}
void actualMove(int x, int y) {
context.mouseX = x;
context.mouseY = y;
context.desiredDraggableX = x - mouseDownOffsetX;
context.desiredDraggableY = y - mouseDownOffsetY;
context.dragController.dragMove();
}
void makeDraggable(Widget draggable, Widget dragHandle) {
if (dragHandle instanceof SourcesMouseEvents) {
((SourcesMouseEvents) dragHandle).addMouseListener(this);
dragHandleMap.put(dragHandle, draggable);
} else {
throw new RuntimeException("dragHandle must implement SourcesMouseEvents to be draggable");
}
}
void makeNotDraggable(Widget dragHandle) {
if (dragHandleMap.remove(dragHandle) == null) {
throw new RuntimeException("dragHandle was not draggable");
}
((SourcesMouseEvents) dragHandle).removeMouseListener(this);
}
private void doSelectionToggle(Event event) {
Widget widget = dragHandleMap.get(mouseDownWidget);
assert widget != null;
if (!toggleKey(event)) {
context.dragController.clearSelection();
}
context.dragController.toggleSelection(widget);
}
private void dragEndCleanup() {
DOM.releaseCapture(capturingWidget.getElement());
dragging = NOT_DRAGGING;
context.dragEndCleanup();
}
private void drop(int x, int y) {
actualMove(x, y);
// Does the DragController allow the drop?
try {
context.dragController.previewDragEnd();
} catch (VetoDragException ex) {
context.vetoException = ex;
}
context.dragController.dragEnd();
}
private void initCapturingWidget() {
capturingWidget = new FocusPanel();
capturingWidget.setPixelSize(0, 0);
RootPanel.get().add(capturingWidget, 0, 0);
capturingWidget.addMouseListener(this);
capturingWidget.getElement().getStyle().setProperty("visibility", "hidden");
capturingWidget.getElement().getStyle().setProperty("margin", "0px");
capturingWidget.getElement().getStyle().setProperty("border", "none");
}
private void startDragging() {
context.dragStartCleanup();
try {
context.dragController.previewDragStart();
} catch (VetoDragException ex) {
context.vetoException = ex;
mouseDown = false;
return;
}
context.dragController.dragStart();
DOM.setCapture(capturingWidget.getElement());
dragging = DRAGGING_NO_MOVEMENT_YET;
}
private boolean toggleKey(Event event) {
return DOM.eventGetCtrlKey(event) || DOM.eventGetMetaKey(event);
}
}