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.formlayout; import java.util.HashMap; import java.util.Map; import com.google.gwt.dom.client.Element; import com.google.gwt.user.client.ui.Widget; import com.vaadin.client.ComponentConnector; import com.vaadin.client.ConnectorHierarchyChangeEvent; import com.vaadin.client.LayoutManager; import com.vaadin.client.TooltipInfo; import com.vaadin.client.Util; import com.vaadin.client.WidgetUtil; import com.vaadin.client.communication.StateChangeEvent; import com.vaadin.client.ui.AbstractLayoutConnector; import com.vaadin.client.ui.HasErrorIndicator; import com.vaadin.client.ui.LayoutClickEventHandler; import com.vaadin.client.ui.PostLayoutListener; import com.vaadin.client.ui.VFormLayout; import com.vaadin.client.ui.VFormLayout.Caption; import com.vaadin.client.ui.VFormLayout.ErrorFlag; import com.vaadin.client.ui.VFormLayout.VFormLayoutTable; import com.vaadin.client.ui.layout.ElementResizeListener; import com.vaadin.shared.ui.Connect; import com.vaadin.shared.ui.LayoutClickRpc; import com.vaadin.shared.ui.MarginInfo; import com.vaadin.shared.ui.orderedlayout.AbstractOrderedLayoutServerRpc; import com.vaadin.shared.ui.orderedlayout.FormLayoutState; import com.vaadin.ui.FormLayout; @Connect(FormLayout.class) public class FormLayoutConnector extends AbstractLayoutConnector implements PostLayoutListener { /* * Handlers & Listeners */ private LayoutClickEventHandler clickEventHandler = new LayoutClickEventHandler(this) { @Override protected ComponentConnector getChildComponent(com.google.gwt.user.client.Element element) { return Util.getConnectorForElement(getConnection(), getWidget(), element); } @Override protected LayoutClickRpc getLayoutClickRPC() { return getRpcProxy(AbstractOrderedLayoutServerRpc.class); } }; private Map<ComponentConnector, String> oldMaxWidths = null; private static final ElementResizeListener DUMMY_FIRST_CELL_RESIZE_LISTENER = event -> { // Ignore event, listener added just to make measurements available }; // Detects situations when there's something inside the FormLayout that // prevents it from shrinking private ElementResizeListener resizeListener = event -> { LayoutManager layoutManager = getLayoutManager(); double tableWidth = layoutManager.getOuterWidthDouble(getWidget().table.getElement()); double ownWidth = layoutManager.getInnerWidthDouble(getWidget().getElement()); if (ownWidth < tableWidth) { // Something inside the table prevents it from shrinking, // temporarily force column widths double excessWidth = tableWidth - ownWidth; // All td elements in the component column have the same width, // so we only need to check the width of the first one to know // how wide the column is. Element firstComponentTd = findFirstComponentTd(); if (firstComponentTd == null) { // Can't do anything if there are no rows return; } double componentColWidth = layoutManager.getOuterWidthDouble(firstComponentTd); if (componentColWidth == -1) { // Didn't get a proper width reading, best to not touch // anything return; } // Restrict content td width // Round down to prevent interactions with fractional sizes of // other columns int targetWidth = (int) Math.floor(componentColWidth - excessWidth); // Target might be negative if captions are wider than the total // available width targetWidth = Math.max(0, targetWidth); if (oldMaxWidths == null) { oldMaxWidths = new HashMap<>(); } for (ComponentConnector child : getChildComponents()) { Element childElement = child.getWidget().getElement(); if (!oldMaxWidths.containsKey(child)) { oldMaxWidths.put(child, childElement.getPropertyString("maxWidth")); } childElement.getStyle().setPropertyPx("maxWidth", targetWidth); layoutManager.reportOuterWidth(child, targetWidth); } } }; @Override protected void init() { super.init(); getLayoutManager().addElementResizeListener(getWidget().table.getElement(), resizeListener); getLayoutManager().addElementResizeListener(getWidget().getElement(), resizeListener); addComponentCellListener(); } @Override public void onUnregister() { getLayoutManager().removeElementResizeListener(getWidget().table.getElement(), resizeListener); getLayoutManager().removeElementResizeListener(getWidget().getElement(), resizeListener); removeComponentCellListener(); super.onUnregister(); } @Override public FormLayoutState getState() { return (FormLayoutState) super.getState(); } @Override public void onStateChanged(StateChangeEvent stateChangeEvent) { super.onStateChanged(stateChangeEvent); clickEventHandler.handleEventHandlerRegistration(); VFormLayoutTable formLayoutTable = getWidget().table; formLayoutTable.setMargins(new MarginInfo(getState().marginsBitmask)); formLayoutTable.setSpacing(getState().spacing); } @Override public void onConnectorHierarchyChange(ConnectorHierarchyChangeEvent event) { VFormLayout formLayout = getWidget(); VFormLayoutTable formLayoutTable = getWidget().table; removeComponentCellListener(); int childId = 0; formLayoutTable.setRowCount(getChildComponents().size()); for (ComponentConnector child : getChildComponents()) { Widget childWidget = child.getWidget(); Caption caption = formLayoutTable.getCaption(childWidget); if (caption == null) { caption = formLayout.new Caption(child); caption.addClickHandler(formLayoutTable); } ErrorFlag error = formLayoutTable.getError(childWidget); if (error == null) { error = formLayout.new ErrorFlag(child); } formLayoutTable.setChild(childId, childWidget, caption, error); childId++; } for (ComponentConnector oldChild : event.getOldChildren()) { if (oldChild.getParent() == this) { continue; } formLayoutTable.cleanReferences(oldChild.getWidget()); } addComponentCellListener(); } private void addComponentCellListener() { Element td = findFirstComponentTd(); if (td != null) { getLayoutManager().addElementResizeListener(td, DUMMY_FIRST_CELL_RESIZE_LISTENER); } } private void removeComponentCellListener() { Element td = findFirstComponentTd(); if (td != null) { getLayoutManager().removeElementResizeListener(td, DUMMY_FIRST_CELL_RESIZE_LISTENER); } } private Element findFirstComponentTd() { VFormLayoutTable table = getWidget().table; if (table.getRowCount() == 0) { return null; } else { return table.getCellFormatter().getElement(0, VFormLayoutTable.COLUMN_WIDGET); } } @Override public void updateCaption(ComponentConnector component) { getWidget().table.updateCaption(component.getWidget(), component.getState(), component.isEnabled()); boolean hideErrors = false; if (component instanceof HasErrorIndicator) { hideErrors = !((HasErrorIndicator) component).isErrorIndicatorVisible(); } getWidget().table.updateError(component.getWidget(), component.getState().errorMessage, component.getState().errorLevel, hideErrors); } @Override public VFormLayout getWidget() { return (VFormLayout) super.getWidget(); } @Override public TooltipInfo getTooltipInfo(Element element) { TooltipInfo info = null; if (element != getWidget().getElement()) { Object node = WidgetUtil.findWidget(element, VFormLayout.Caption.class); if (node != null) { VFormLayout.Caption caption = (VFormLayout.Caption) node; info = caption.getOwner().getTooltipInfo(element); } else { node = WidgetUtil.findWidget(element, VFormLayout.ErrorFlag.class); if (node != null) { VFormLayout.ErrorFlag flag = (VFormLayout.ErrorFlag) node; info = flag.getOwner().getTooltipInfo(element); } } } if (info == null) { info = super.getTooltipInfo(element); } return info; } @Override public boolean hasTooltip() { /* * Tooltips are fetched from child connectors -> there's no quick way of * checking whether there might a tooltip hiding somewhere */ return true; } @Override public void postLayout() { if (oldMaxWidths != null) { for (ComponentConnector child : getChildComponents()) { Element childNode = child.getWidget().getElement(); String oldValue = oldMaxWidths.get(child); if (oldValue == null) { childNode.getStyle().clearProperty("maxWidth"); } else { childNode.getStyle().setProperty("maxWidth", oldValue); } } oldMaxWidths = null; } } }