Java tutorial
/* * Copyright 2010 kk-electronic a/s. * * This file is part of KKPortal. * * KKPortal is free software: you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published * by the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * KKPortal is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with KKPortal. If not, see <http://www.gnu.org/licenses/>. * */ package com.kk_electronic.kkportal.core.ui; import java.util.HashSet; import java.util.List; import com.google.gwt.core.client.Scheduler; import com.google.gwt.dom.client.Style.Unit; import com.google.gwt.event.dom.client.MouseDownEvent; import com.google.gwt.event.dom.client.MouseDownHandler; import com.google.gwt.event.dom.client.MouseUpEvent; import com.google.gwt.layout.client.Layout; import com.google.gwt.user.client.Command; import com.google.gwt.user.client.ui.IsWidget; import com.google.gwt.user.client.ui.LayoutPanel; import com.google.gwt.user.client.ui.Widget; import com.google.inject.Inject; import com.kk_electronic.kkportal.core.dnd.DND; import com.kk_electronic.kkportal.core.dnd.DragSource; import com.kk_electronic.kkportal.core.dnd.DND.DropSink; public class GroupDisplay<T extends IsWidget & KnownHeight & DragSource> implements DropSink<T>, IsWidget { LayoutPanel canvas = new LayoutPanel(); private final DND<T> dnd; private double margin = 1; private Unit marginunit = Unit.EM; public static interface Handler<T> { public void onElementDrop(double x, int y, T element); } private Handler<T> handler; public void setHandler(Handler<T> handler) { this.handler = handler; } @Inject public GroupDisplay(DND<T> dnd) { this.dnd = dnd; dnd.registerDropSink(this); } private native Layout iHateJavaProtection(LayoutPanel layoutPanel) /*-{ return layoutPanel.@com.google.gwt.user.client.ui.LayoutPanel::layout; }-*/; HashSet<Widget> displayed = new HashSet<Widget>(); public void setWidgets(List<List<T>> widgets) { if (canvas.isAttached() == false) { return; } if (widgets == null) { canvas.clear(); displayed.clear(); return; } HashSet<Widget> needRemoval = new HashSet<Widget>(displayed); Layout l = iHateJavaProtection(canvas); double x = margin * l.getUnitSize(marginunit, false) / l.getUnitSize(Unit.PCT, false); double y = margin * l.getUnitSize(marginunit, true); double left = x; for (List<T> column : widgets) { double top = y; //TODO: Support weighted column sizes double width = (100.0 - x) / widgets.size() - x; for (final T face : column) { final Widget widget = face.asWidget(); int height = face.getDesiredHeight(); if (!displayed.contains(widget)) { canvas.add(widget); canvas.getWidgetContainerElement(widget).getStyle().clearOverflow(); displayed.add(widget); face.getDragHandle().addMouseDownHandler(new MouseDownHandler() { @Override public void onMouseDown(MouseDownEvent event) { dnd.startDrag(event, face); } }); } canvas.setWidgetLeftWidth(widget, left, Unit.PCT, width, Unit.PCT); canvas.setWidgetTopHeight(widget, top, Unit.PX, height, Unit.PX); top += height + y; needRemoval.remove(face); } left += width + x; } for (Widget toRemove : needRemoval) { canvas.remove(toRemove); displayed.remove(toRemove); //TODO:remove handler } canvas.animate(150); } @Override public boolean Drop(MouseUpEvent event, final T element) { Widget widget = element.asWidget(); int height = widget.getOffsetHeight(); event.setRelativeElement(canvas.getElement()); final int x = event.getX(); final int y = event.getY(); /* * Note must be 100.0 and not 100 since the later would result in * integer division which most likely would be 0 */ double width = (100.0 * widget.getOffsetWidth()) / canvas.getOffsetWidth(); final int top = widget.getAbsoluteTop() - canvas.getAbsoluteTop(); final double left = (100.0 * (widget.getAbsoluteLeft() - canvas.getAbsoluteLeft())) / canvas.getOffsetWidth(); final double xpct = 100.0 * x / canvas.getOffsetWidth(); canvas.add(widget); canvas.getWidgetContainerElement(widget).getStyle().clearOverflow(); canvas.setWidgetTopHeight(widget, top, Unit.PX, height, Unit.PX); canvas.setWidgetLeftWidth(widget, left, Unit.PCT, width, Unit.PCT); if (handler != null) { Scheduler.get().scheduleDeferred(new Command() { @Override public void execute() { handler.onElementDrop(xpct, y, element); } }); return true; } return false; } @Override public Widget asWidget() { return canvas; } public boolean checkForResizes() { if (canvas.getWidgetCount() == 0) return false; //ArrayList<Pair<Integer, Integer>> worklist = new ArrayList<Pair<Integer,Integer>>(); boolean newSizes = false; for (int i = 0, l = canvas.getWidgetCount(); i < l; i++) { Widget widget = canvas.getWidget(i); int desiredHeight = 0; if (widget instanceof KnownHeight) { KnownHeight heightWidget = (KnownHeight) widget; desiredHeight = heightWidget.getDesiredHeight(); if (desiredHeight != heightWidget.getLastHeight()) { //worklist.add(new Pair(heightWidget.getId(), desiredHeight)); heightWidget.saveHeight(desiredHeight); newSizes = true; } } } return newSizes; } }