Java tutorial
/* * Copyright 2009 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.util; import com.allen_sauer.gwt.dnd.client.util.impl.DOMUtilImpl; import com.google.gwt.core.client.GWT; import com.google.gwt.core.client.JsArray; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.NativeEvent; import com.google.gwt.dom.client.Touch; import com.google.gwt.user.client.Window; import com.google.gwt.user.client.ui.IndexedPanel; import com.google.gwt.user.client.ui.Widget; /** * Provides DOM utility methods. */ public class DOMUtil { /** * Whether or not debugging is enabled. */ public static final boolean DEBUG = false; private static DOMUtilImpl impl; static { impl = (DOMUtilImpl) GWT.create(DOMUtilImpl.class); } /** * Adjust line breaks within in the provided title for optimal readability and display length for * the current user agent. * * @param title the desired raw text * @return formatted and escaped text */ public static String adjustTitleForBrowser(String title) { return impl.adjustTitleForBrowser(title).replaceAll("</?code>", "`"); } /** * Cancel all currently selected region(s) on the current page. */ public static void cancelAllDocumentSelections() { impl.cancelAllDocumentSelections(); } /** * Set a widget's border style for debugging purposes. * * @param widget the widget to color * @param color the desired border color */ public static void debugWidgetWithColor(Widget widget, String color) { if (DEBUG) { widget.getElement().getStyle().setProperty("border", "2px solid " + color); } } /** * Set an element's location as fast as possible, avoiding some of the overhead in * {@link com.google.gwt.user.client.ui.AbsolutePanel#setWidgetPosition(Widget, int, int)} . * * @param elem the element's whose position is to be modified * @param left the left pixel offset * @param top the top pixel offset */ public static void fastSetElementPosition(Element elem, int left, int top) { elem.getStyle().setPropertyPx("left", left); elem.getStyle().setPropertyPx("top", top); } /** * Find child widget intersection at the provided location using the provided comparator strategy. * * TODO Change IndexedPanel -> InsertPanel * * @param parent the parent widget which contains the children to be compared * @param location the location of the intersection * @param comparator the comparator strategy * @return the index of the matching child */ public static int findIntersect(IndexedPanel parent, Location location, LocationWidgetComparator comparator) { int widgetCount = parent.getWidgetCount(); // short circuit in case dropTarget has no children if (widgetCount == 0) { return 0; } // use the first widget as a proxy for parent's direction boolean rtl = isRtl(parent.getWidget(0)); if (DEBUG) { for (int i = 0; i < widgetCount; i++) { debugWidgetWithColor(parent, i, "white"); } } // binary search over range of widgets to find intersection int low = 0; int high = widgetCount; while (true) { int mid = (low + high) / 2; assert mid >= low; assert mid < high; Widget widget = parent.getWidget(mid); WidgetArea midArea = new WidgetArea(widget, null); if (mid == low) { if (mid == 0) { if (comparator.locationIndicatesIndexFollowingWidget(midArea, location)) { debugWidgetWithColor(parent, high, "green"); return high; } else { debugWidgetWithColor(parent, mid, "green"); return mid; } } else { debugWidgetWithColor(parent, high, "green"); return high; } } if (midArea.getBottom() < location.getTop()) { debugWidgetWithColor(parent, mid, "blue"); low = mid; } else if (midArea.getTop() > location.getTop()) { debugWidgetWithColor(parent, mid, "red"); high = mid; } else if (midArea.getRight() < location.getLeft()) { debugWidgetWithColor(parent, mid, "blue"); if (rtl) { high = mid; } else { low = mid; } } else if (midArea.getLeft() > location.getLeft()) { debugWidgetWithColor(parent, mid, "red"); if (rtl) { low = mid; } else { high = mid; } } else { if (comparator.locationIndicatesIndexFollowingWidget(midArea, location)) { debugWidgetWithColor(parent, mid + 1, "green"); return mid + 1; } else { debugWidgetWithColor(parent, mid, "green"); return mid; } } } } public static boolean isRtl(Widget widget) { Element elem = widget.getElement(); return "rtl".equals(getEffectiveStyle(elem, "direction")); } /** * Gets an element's CSS based 'border-left-width' in pixels or <code>0</code> (zero) when the * element is hidden. * * @param elem the element to be measured * @return the width of the left CSS border in pixels */ public static int getBorderLeft(Element elem) { return impl.getBorderLeft(elem); } /** * Gets an element's CSS based 'border-top-widget' in pixels or <code>0</code> (zero) when the * element is hidden. * * @param elem the element to be measured * @return the width of the top CSS border in pixels */ public static int getBorderTop(Element elem) { return impl.getBorderTop(elem); } /** * Gets an element's client height in pixels or <code>0</code> (zero) when the element is hidden. * This is equal to offset height minus the top and bottom CSS borders. * * @param elem the element to be measured * @return the element's client height in pixels */ public static int getClientHeight(Element elem) { return impl.getClientHeight(elem); } /** * Gets an element's client widget in pixels or <code>0</code> (zero) when the element is hidden. * This is equal to offset width minus the left and right CSS borders. * * @param elem the element to be measured * @return the element's client width in pixels */ public static int getClientWidth(Element elem) { return impl.getClientWidth(elem); } public static String getEffectiveStyle(Element elem, String styleName) { return impl.getEffectiveStyle(elem, styleName); } /** * Gets the sum of an element's left and right CSS borders in pixels. * * @param widget the widget to be measured * @return the total border width in pixels */ public static int getHorizontalBorders(Widget widget) { return impl.getHorizontalBorders(widget); } /** * Determine an element's node name via the <code>nodeName</code> property. * * @param elem the element whose node name is to be determined * @return the element's node name */ public static String getNodeName(Element elem) { return elem.getNodeName(); } /** * Gets the sum of an element's top and bottom CSS borders in pixels. * * @param widget the widget to be measured * @return the total border height in pixels */ public static int getVerticalBorders(Widget widget) { return impl.getVerticalBorders(widget); } /** * Report a fatal exception via <code>Window.alert()</code> than throw a * <code>RuntimeException</code>. * * @param msg the message to report * @throws RuntimeException a new exception based on the provided message */ public static void reportFatalAndThrowRuntimeException(String msg) throws RuntimeException { msg = "gwt-dnd warning: " + msg; Window.alert(msg); throw new RuntimeException(msg); } /** * Set the browser's status bar text, if supported and enabled in the client browser. * * @param text the message to use as the window status */ public static void setStatus(String text) { Window.setStatus(text); } /** * TODO Change IndexedPanel -> InsertPanel */ private static void debugWidgetWithColor(IndexedPanel parent, int index, String color) { if (DEBUG) { if (index >= parent.getWidgetCount()) { debugWidgetWithColor(parent.getWidget(parent.getWidgetCount() - 1), color); } else { debugWidgetWithColor(parent.getWidget(index), color); } } } public native static NativeEvent createTouchEndEvent(boolean bubbles, boolean cancelable, int detail, boolean ctrlKey, boolean altKey, boolean shiftKey, boolean metaKey, JsArray<Touch> changedTouches) /*-{ var evt = $doc.createEvent('TouchEvent'); var view = null; evt.initUIEvent("touchend", bubbles, cancelable, view, detail); evt.changedTouches = changedTouches; return evt; }-*/; }