Java tutorial
/* * Copyright 2000-2018 Vaadin Ltd. * * 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.vaadin.client.ui; import com.google.gwt.dom.client.DivElement; import com.google.gwt.dom.client.Document; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.Style; import com.google.gwt.user.client.DOM; import com.google.gwt.user.client.ui.ComplexPanel; import com.google.gwt.user.client.ui.SimplePanel; import com.google.gwt.user.client.ui.Widget; import com.vaadin.client.StyleConstants; import com.vaadin.client.VCaption; public class VAbsoluteLayout extends ComplexPanel { /** Tag name for widget creation. */ public static final String TAGNAME = "absolutelayout"; /** Class name, prefix in styling. */ public static final String CLASSNAME = "v-absolutelayout"; private DivElement marginElement; protected final Element canvas = DOM.createDiv(); /** * Default constructor. */ public VAbsoluteLayout() { setElement(Document.get().createDivElement()); marginElement = Document.get().createDivElement(); canvas.getStyle().setProperty("position", "relative"); canvas.getStyle().setProperty("overflow", "hidden"); marginElement.appendChild(canvas); getElement().appendChild(marginElement); setStyleName(CLASSNAME); } /* * (non-Javadoc) * * @see * com.google.gwt.user.client.ui.Panel#add(com.google.gwt.user.client.ui * .Widget) */ @Override public void add(Widget child) { AbsoluteWrapper wrapper = new AbsoluteWrapper(child); wrapper.updateStyleNames(); super.add(wrapper, canvas); } /* * (non-Javadoc) * * @see * com.google.gwt.user.client.ui.ComplexPanel#remove(com.google.gwt.user * .client.ui.Widget) */ @Override public boolean remove(Widget w) { AbsoluteWrapper wrapper = getChildWrapper(w); if (wrapper != null) { wrapper.destroy(); return super.remove(wrapper); } return super.remove(w); } /** * Does this layout contain a widget. * * @param widget * The widget to check * @return Returns true if the widget is in this layout, false if not */ public boolean contains(Widget widget) { return getChildWrapper(widget) != null; } /* * (non-Javadoc) * * @see com.google.gwt.user.client.ui.ComplexPanel#getWidget(int) */ @Override public Widget getWidget(int index) { for (int i = 0, j = 0; i < super.getWidgetCount(); i++) { Widget w = super.getWidget(i); if (w instanceof AbsoluteWrapper) { if (j == index) { return w; } else { j++; } } } return null; } /* * (non-Javadoc) * * @see com.google.gwt.user.client.ui.ComplexPanel#getWidgetCount() */ @Override public int getWidgetCount() { int counter = 0; for (int i = 0; i < super.getWidgetCount(); i++) { if (super.getWidget(i) instanceof AbsoluteWrapper) { counter++; } } return counter; } /* * (non-Javadoc) * * @see * com.google.gwt.user.client.ui.ComplexPanel#getWidgetIndex(com.google. * gwt.user.client.ui.Widget) */ @Override public int getWidgetIndex(Widget child) { for (int i = 0, j = 0; i < super.getWidgetCount(); i++) { Widget w = super.getWidget(i); if (w instanceof AbsoluteWrapper) { if (child == w) { return j; } else { j++; } } } return -1; } /** * Sets a caption for a contained widget. * * @param child * The child widget to set the caption for * @param caption * The caption of the widget */ public void setWidgetCaption(Widget child, VCaption caption) { AbsoluteWrapper wrapper = getChildWrapper(child); if (wrapper != null) { if (caption != null) { if (!getChildren().contains(caption)) { super.add(caption, canvas); } wrapper.setCaption(caption); caption.updateCaption(); wrapper.updateCaptionPosition(); } else if (wrapper.getCaption() != null) { wrapper.setCaption(null); } } } /** * Set the position of the widget in the layout. The position is a CSS * property string using properties such as top,left,right,top * * @param child * The child widget to set the position for * @param position * The position string */ public void setWidgetPosition(Widget child, String position) { AbsoluteWrapper wrapper = getChildWrapper(child); if (wrapper != null) { wrapper.setPosition(position); } } /** * Get the caption for a widget. * * @param child * The child widget to get the caption of */ public VCaption getWidgetCaption(Widget child) { AbsoluteWrapper wrapper = getChildWrapper(child); if (wrapper != null) { return wrapper.getCaption(); } return null; } /** * Get the pixel width of an slot in the layout. * * @param child * The widget in the layout. * @return Returns the size in pixels, or 0 if child is not in the layout */ public int getWidgetSlotWidth(Widget child) { AbsoluteWrapper wrapper = getChildWrapper(child); if (wrapper != null) { return wrapper.getOffsetWidth(); } return 0; } /** * Get the pixel height of an slot in the layout. * * @param child * The widget in the layout * @return Returns the size in pixels, or 0 if the child is not in the * layout */ public int getWidgetSlotHeight(Widget child) { AbsoluteWrapper wrapper = getChildWrapper(child); if (wrapper != null) { return wrapper.getOffsetHeight(); } return 0; } /** * Get the wrapper for a widget. * * @param child * The child to get the wrapper for * @return */ protected AbsoluteWrapper getChildWrapper(Widget child) { for (Widget w : getChildren()) { if (w instanceof AbsoluteWrapper) { AbsoluteWrapper wrapper = (AbsoluteWrapper) w; if (wrapper.getWidget() == child) { return wrapper; } } } return null; } /* * (non-Javadoc) * * @see * com.google.gwt.user.client.ui.UIObject#setStylePrimaryName(java.lang. * String) */ @Override public void setStylePrimaryName(String style) { updateStylenames(style); } /* * (non-Javadoc) * * @see * com.google.gwt.user.client.ui.UIObject#setStyleName(java.lang.String) */ @Override public void setStyleName(String style) { super.setStyleName(style); updateStylenames(style); addStyleName(StyleConstants.UI_LAYOUT); } /** * Updates all style names contained in the layout. * * @param primaryStyleName * The style name to use as primary */ protected void updateStylenames(String primaryStyleName) { super.setStylePrimaryName(primaryStyleName); canvas.setClassName(getStylePrimaryName() + "-canvas"); canvas.setClassName(getStylePrimaryName() + "-margin"); for (Widget w : getChildren()) { if (w instanceof AbsoluteWrapper) { AbsoluteWrapper wrapper = (AbsoluteWrapper) w; wrapper.updateStyleNames(); } } } /** * Performs a vertical layout of the layout. Should be called when a widget * is added or removed */ public void layoutVertically() { layout(); } /** * Performs an horizontal layout. Should be called when a widget is add or * removed */ public void layoutHorizontally() { layout(); } private void layout() { for (Widget widget : getChildren()) { if (widget instanceof AbsoluteWrapper) { AbsoluteWrapper wrapper = (AbsoluteWrapper) widget; wrapper.updateCaptionPosition(); } } } /** * Cleanup old wrappers which have been left empty by other inner layouts * moving the widget from the wrapper into their own hierarchy. This usually * happens when a call to setWidget(widget) is done in an inner layout which * automatically detaches the widget from the parent, in this case the * wrapper, and re-attaches it somewhere else. This has to be done in the * layout phase since the order of the hierarchy events are not defined. */ public void cleanupWrappers() { for (Widget widget : getChildren()) { if (widget instanceof AbsoluteWrapper) { AbsoluteWrapper wrapper = (AbsoluteWrapper) widget; if (wrapper.getWidget() == null) { wrapper.destroy(); super.remove(wrapper); continue; } } } } /** * Sets style names for the wrapper wrapping the widget in the layout. The * style names will be prefixed with v-absolutelayout-wrapper. * * @param widget * The widget which wrapper we want to add the stylenames to * @param stylenames * The style names that should be added to the wrapper */ public void setWidgetWrapperStyleNames(Widget widget, String... stylenames) { AbsoluteWrapper wrapper = getChildWrapper(widget); if (wrapper == null) { throw new IllegalArgumentException( "No wrapper for widget found, has the widget been added to the layout?"); } wrapper.setWrapperStyleNames(stylenames); } /** * Internal wrapper for wrapping widgets in the Absolute layout. */ protected class AbsoluteWrapper extends SimplePanel { private String css; private String left; private String top; private String right; private String bottom; private String zIndex; private VCaption caption; private String[] extraStyleNames; /** * Constructor. * * @param child * The child to wrap */ public AbsoluteWrapper(Widget child) { setWidget(child); } /** * Get the caption of the wrapper. */ public VCaption getCaption() { return caption; } /** * Set the caption for the wrapper. * * @param caption * The caption for the wrapper */ public void setCaption(VCaption caption) { if (caption != null) { this.caption = caption; } else if (this.caption != null) { this.caption.removeFromParent(); this.caption = caption; } } /** * Removes the wrapper caption and itself from the layout. */ public void destroy() { if (caption != null) { caption.removeFromParent(); } removeFromParent(); } /** * Set the position for the wrapper in the layout. * * @param position * The position string */ public void setPosition(String position) { if (css == null || !css.equals(position)) { css = position; top = right = bottom = left = zIndex = null; if (!css.isEmpty()) { for (String property : css.split(";")) { String[] keyValue = property.split(":"); if (keyValue[0].equals("left")) { left = keyValue[1]; } else if (keyValue[0].equals("top")) { top = keyValue[1]; } else if (keyValue[0].equals("right")) { right = keyValue[1]; } else if (keyValue[0].equals("bottom")) { bottom = keyValue[1]; } else if (keyValue[0].equals("z-index")) { zIndex = keyValue[1]; } } } // ensure ne values Style style = getElement().getStyle(); style.setProperty("zIndex", zIndex); style.setProperty("top", top); style.setProperty("left", left); style.setProperty("right", right); style.setProperty("bottom", bottom); } updateCaptionPosition(); } /** * Updates the caption position by using element offset left and top */ private void updateCaptionPosition() { if (caption != null) { Style style = caption.getElement().getStyle(); style.setProperty("position", "absolute"); style.setPropertyPx("left", getElement().getOffsetLeft()); style.setPropertyPx("top", getElement().getOffsetTop() - caption.getHeight()); } } /** * Sets the style names of the wrapper. Will be prefixed with the * v-absolutelayout-wrapper prefix * * @param stylenames * The wrapper style names */ public void setWrapperStyleNames(String... stylenames) { extraStyleNames = stylenames; updateStyleNames(); } /** * Updates the style names using the primary style name as prefix. */ protected void updateStyleNames() { setStyleName(VAbsoluteLayout.this.getStylePrimaryName() + "-wrapper"); if (extraStyleNames != null) { for (String stylename : extraStyleNames) { addStyleDependentName(stylename); } } } } }