Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2005 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.examples.launcher; import java.lang.reflect.Method; import org.eclipse.swt.SWT; import org.eclipse.swt.events.SelectionEvent; import org.eclipse.swt.events.SelectionListener; import org.eclipse.swt.events.TreeEvent; import org.eclipse.swt.events.TreeListener; import org.eclipse.swt.layout.FillLayout; import org.eclipse.swt.layout.GridData; import org.eclipse.swt.layout.GridLayout; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Group; import org.eclipse.swt.widgets.Shell; import org.eclipse.swt.widgets.Text; import org.eclipse.swt.widgets.Tree; import org.eclipse.swt.widgets.TreeItem; import org.eclipse.ui.IWorkbenchPage; import org.eclipse.ui.IWorkbenchPart; import org.eclipse.ui.IWorkbenchPartSite; import org.eclipse.ui.PartInitException; import org.eclipse.ui.part.ViewPart; /** * Launcher uses <code>org.eclipse.swt</code> * to launch the other registered examples. * * @see ViewPart */ public class LauncherView extends ViewPart { private Shell workbenchShell; private Tree launchTree; private Text descriptionText; private Button runButton; /** * Constructs a LauncherView. */ public LauncherView() { LauncherPlugin.initResources(); } /** * Creates the example. * * @see ViewPart#createPartControl */ @Override public void createPartControl(Composite parent) { workbenchShell = getSite().getShell(); parent.setLayout(new SplitLayout()); Group launchGroup = new Group(parent, SWT.NONE); launchGroup.setText(LauncherPlugin.getResourceString("view.launchGroup.text")); GridLayout gridLayout = new GridLayout(); gridLayout.numColumns = 2; launchGroup.setLayout(gridLayout); launchTree = new Tree(launchGroup, SWT.BORDER | SWT.V_SCROLL | SWT.H_SCROLL); GridData gridData = new GridData(GridData.FILL_HORIZONTAL | GridData.FILL_VERTICAL); gridData.horizontalSpan = 2; launchTree.setLayoutData(gridData); launchTree.addSelectionListener(new SelectionListener() { @Override public void widgetSelected(SelectionEvent event) { final ItemDescriptor item = getSelectedItem(); setDescriptionByItem(item); } @Override public void widgetDefaultSelected(SelectionEvent event) { final ItemDescriptor item = getSelectedItem(); setDescriptionByItem(item); if (item.getMainType() == null && item.getView() == null) { // Category selected, so just expand/colapse the node TreeItem treeItem = (TreeItem) event.item; boolean expanded = treeItem.getExpanded(); if (treeItem != null) treeItem.setExpanded(!expanded); treeItem.setImage(LauncherPlugin.images[expanded ? LauncherPlugin.liClosedFolder : LauncherPlugin.liOpenFolder]); } else { launchItem(getSelectedItem()); } } }); launchTree.addTreeListener(new TreeListener() { @Override public void treeCollapsed(TreeEvent event) { final TreeItem item = (TreeItem) event.item; if (item == null) return; item.setImage(LauncherPlugin.images[LauncherPlugin.liClosedFolder]); } @Override public void treeExpanded(TreeEvent event) { final TreeItem item = (TreeItem) event.item; if (item == null) return; item.setImage(LauncherPlugin.images[LauncherPlugin.liOpenFolder]); } }); runButton = new Button(launchGroup, SWT.PUSH); runButton.setText(LauncherPlugin.getResourceString("view.launchButton.text")); runButton.addSelectionListener(new SelectionListener() { @Override public void widgetSelected(SelectionEvent event) { launchItem(getSelectedItem()); } @Override public void widgetDefaultSelected(SelectionEvent event) { } }); Group descriptionGroup = new Group(parent, SWT.NONE); descriptionGroup.setText(LauncherPlugin.getResourceString("view.descriptionGroup.text")); descriptionGroup.setLayout(new FillLayout()); descriptionText = new Text(descriptionGroup, SWT.MULTI | SWT.BORDER | SWT.WRAP | SWT.V_SCROLL | SWT.READ_ONLY); setDescriptionByItem(null); setItemDescriptors(LauncherPlugin.getLaunchItemTree()); } /** * Called when we must grab focus. * * @see org.eclipse.ui.part.ViewPart#setFocus */ @Override public void setFocus() { launchTree.setFocus(); runButton.getShell().setDefaultButton(runButton); } /** * Called when the View is to be disposed */ @Override public void dispose() { workbenchShell = null; launchTree = null; descriptionText = null; runButton = null; super.dispose(); } /** * Installs a new launch list. * * @param newRoot the new tree of launch items for the UI */ public void setItemDescriptors(final ItemTreeNode newRoot) { if (workbenchShell == null) return; workbenchShell.getDisplay().syncExec(new Runnable() { @Override public void run() { if ((launchTree == null) || (launchTree.isDisposed())) return; launchTree.removeAll(); for (ItemTreeNode node = newRoot.getFirstChild(); node != null; node = node.getNextSibling()) { doNode(node, new TreeItem(launchTree, SWT.NONE)); // top-level TreeItem } } private void addGroup(TreeItem parent, ItemTreeNode node) { for (; node != null; node = node.getNextSibling()) { doNode(node, new TreeItem(parent, SWT.NONE)); // TreeItem at depth > 0 } } private void doNode(ItemTreeNode node, TreeItem treeItem) { final ItemDescriptor item = node.getDescriptor(); treeItem.setText(item.getName()); treeItem.setData(item); if (node.getDescriptor().isFolder()) { treeItem.setExpanded(false); treeItem.setImage(LauncherPlugin.images[LauncherPlugin.liClosedFolder]); } else { treeItem.setImage(node.getDescriptor().getIcon()); } addGroup(treeItem, node.getFirstChild()); } }); } /** * Runs the specified launch item. * * @param itemDescriptor the launch item to execute */ private void launchItem(ItemDescriptor itemDescriptor) { /* Case 1: The launch item is a view */ String pluginViewId = itemDescriptor.getView(); if (pluginViewId != null) { final IWorkbenchPart workbenchPart = this; final IWorkbenchPartSite workbenchPartSite = workbenchPart.getSite(); final IWorkbenchPage workbenchPage = workbenchPartSite.getPage(); try { workbenchPage.showView(pluginViewId); } catch (PartInitException e) { LauncherPlugin.logError(LauncherPlugin.getResourceString("run.error.Invocation"), e); } return; } /* Case 2: The launch item is a standalone program */ if (workbenchShell == null) return; try { Object instance = itemDescriptor.createItemInstance(); if (instance != null) { Display display = workbenchShell.getDisplay(); Method openMethod = instance.getClass().getDeclaredMethod("open", new Class[] { Display.class }); openMethod.invoke(instance, display); } } catch (NoSuchMethodException e) { LauncherPlugin.logError(LauncherPlugin.getResourceString("run.error.DoesNotImplementMethod"), null); } catch (Exception e) { LauncherPlugin.logError(LauncherPlugin.getResourceString("run.error.CouldNotInstantiateClass"), e); } } /** * Obtains the selected launch item. * * @return the currently selected ItemDescriptor */ private ItemDescriptor getSelectedItem() { final TreeItem[] selections = launchTree.getSelection(); if (selections.length == 0) return null; final ItemDescriptor itemDescriptor = (ItemDescriptor) selections[0].getData(); return itemDescriptor; } /** * Sets the currently visible description text to reflect that of a particular ItemDescriptor. * * @param itemDescriptor the launch item whose description is to be displayed, or null if none */ private void setDescriptionByItem(ItemDescriptor itemDescriptor) { String description; if (itemDescriptor == null) { description = LauncherPlugin.getResourceString("launchitem.Null.description"); if (runButton != null) runButton.setEnabled(false); } else { description = itemDescriptor.getDescription(); if (description == null) description = LauncherPlugin.getResourceString("launchitem.Missing.description"); if (runButton != null) { runButton.setEnabled(itemDescriptor.getView() != null || itemDescriptor.getMainType() != null); } } descriptionText.setText(description); } }