Eclipse提供了非常多的view，從表現(xiàn)形式來說可分為table view和tree view；從結(jié)構(gòu)上來說可分成三類：Common navigator view, Pagebook view, Task-oriented view。一般情況下，CNV與Resource有關(guān)，pagebook跟selection有關(guān)，而task-oriented 為自定義的視圖。基本所有的** explorer都是CNV型的view，基本所有主要插件都有CNV的影子比如IDE，Navigator, Team，JDT, CDT, DTP等。為什么要使用CNV?
Paper Napkin的文章說的很清楚了,我的看法是，對于怎樣面對大批量+復雜應用的二次抽象(view超多，view內(nèi)容聯(lián)系超復雜緊密)，CNV提供了一個很好的完整實例。
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代碼下載，下載后import到Eclipse 3.4.1+JDK 1.6,run/debug即可。
CNV的視圖特征：
10分鐘，一個CNV Resource View
- 新建一個plugin項目，名字 com.lifesting.hush，將圖標解壓縮到項目下，刷新，打開MANIFEST.MF，在build項里面將icon目錄鉤上。
- 定位Dependencies項，依次加入 org.eclipse.ui.navigator,org.eclipse.ui.navigator.resources,org.eclipse.ui.ide,org.eclipse.jface.text,org.eclipse.ui.editors, org.eclipse.core.resources,org.eclipse.ui.views插件。
- 配置一個view extension, 如下圖：
需要注意的是，這個view的implementation是navigator插件里面的CommonNavigator，目前我們不需要手寫任何代碼。
- 使用Extension Point org.eclipse.ui.navigator.viewer, new一個viewer，viewId設置為 com.lifesting.hush.view.cnf，popMenuId暫時置空；new一個viewerContentBinding，viewId不變，添加一個includes子節(jié)點，然后在其上添加一個contentExtension，屬性pattern為org.eclipse.ui.navigator.resourceContent,isRoot為true.
- 啟動，點擊菜單Window->Show View->General->Html Explorer，就可以看到效果了，如果view是空白，也不是bug，在左邊的Pakcage Explorer或Resource Explorer新建一個項目，然后關(guān)閉Html Explorer再打開，就會看到Html Explorer顯示的和Resource Explorer一模一樣的項目結(jié)構(gòu)。
雖然這個Html Explorer出來了，但設置的org.eclipse.ui.navigator.resourceContent哪來的？怎么定義的？怎么添加右鍵菜單？Link為啥無效？怎樣定制這個顯示？CNF好像也沒有顯著的特點阿？不著急，逐一搞定，從頭開始，最終的效果會是這樣的：
CNV的核心是navigatorContent，所有操作都是圍繞它展開的(可以選擇org.eclipse.ui.navigator.navigatorContent,選擇find references，看看SDK都提供了哪些content)，我們這個Html Explorer為了把過程將的更清楚，將使用兩個自定義的navigatorContent。下面是步驟：
- 通過extension point org.eclipse.ui.navigator.navigatorContent 新建一個id為com.lifesting.cnf.directorycontent的navigatorContent，activatorByDefault=true，LabelProvider=
org.eclipse.ui.model.WorkbenchLabelProvider，而contentProvider需要新建一個類，非常簡單，就是遍歷IProject或IFolder的子資源(Folder或File)。它的getElement方法實現(xiàn)：
@Override
public Object[] getElements(Object inputElement) {
if (inputElement instanceof IProject)
{
try {
return ((IProject)inputElement).members();
} catch (CoreException e) {
e.printStackTrace();
}
}
else if (inputElement instanceof IFolder){
try {
return ((IFolder)inputElement).members();
} catch (CoreException e) {
e.printStackTrace();
}
}
return EMPTY;
}
- 每個navigatorContent都有triggerPoints，很顯然剛才定義的content通過IProject和IFolder來觸發(fā)view tree生成。在這個content下面new 一個triggerPoints，再new兩個instanceof分別指向IProject和IFile。
- 在定義actionProvider的時候，需要知道selection大致的類型，在這個content下面new一個possibleChildren，再new一個instanceof 先后IResource(IFile或者IFolder）。
- 通過extension point org.eclipse.ui.viewActions給ui view添加一個action用來設置content的Root，它的class如下：
//bind to mycnfview
public class OpenDirectoryAction implements IViewActionDelegate {
private MyCnfView view;
public OpenDirectoryAction() {
}
@Override
public void init(IViewPart view) {
this.view = (MyCnfView) view;
}
@Override
public void run(IAction action) {
DirectoryDialog dir_dialog = new DirectoryDialog(view.getSite()
.getShell());
String dir_location = retriveSavedDirLocation();
initDialog(dir_dialog, dir_location);
String dir = dir_dialog.open();
if (null != dir && !dir.equals(dir_location)) {
saveDirLocation(dir);
createPhantomProject(dir);
fireDirChanged(dir);
}
}
private void createPhantomProject(String dir_location) {
IProject project = ResourcesPlugin.getWorkspace().getRoot().getProject(MyCnfView.PHANTOM_PROJECT_NAME);
// 1 delete previous defined project
if (project.exists()) {
try {
project.delete(false, true, null);
} catch (CoreException e) {
e.printStackTrace();
}
}
// 2 create new project with the same name
final IProjectDescription desc = ResourcesPlugin.getWorkspace().newProjectDescription(MyCnfView.PHANTOM_PROJECT_NAME);
desc.setLocationURI(new File(dir_location).toURI());
IRunnableWithProgress op = new IRunnableWithProgress() {
public void run(IProgressMonitor monitor)
throws InvocationTargetException {
CreateProjectOperation op = new CreateProjectOperation(desc,
"Build Algorithm Library");
try {
PlatformUI.getWorkbench().getOperationSupport()
.getOperationHistory().execute(
op,
monitor,
WorkspaceUndoUtil
.getUIInfoAdapter(view.getSite().getShell()));
} catch (ExecutionException e) {
throw new InvocationTargetException(e);
}
}
};
try {
view.getSite().getWorkbenchWindow().run(false, false, op);
} catch (InvocationTargetException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
// 3 add the new created project to default workingset
if (project.exists()) {
view.getSite().getWorkbenchWindow().getWorkbench().getWorkingSetManager().addToWorkingSets(project,
new IWorkingSet[] {});
//4 waiting the project is ready(file structure is built)
try {
project.refreshLocal(IResource.DEPTH_INFINITE, null);
} catch (CoreException e) {
e.printStackTrace();
}
}
}
//...略..輔助方法
}
代碼要表達的就是建立一個隱含的project，將action取得的directory下所有的文件都倒入到項目中來。
- 將ui view的class從CommonNavigator變?yōu)橐粋€它的子類MyCnfView:
public class MyCnfView extends CommonNavigator {
public static final String KEY_DIR_LOCATION="com.lifesting.cnf.myview_location";
public static final String PHANTOM_PROJECT_NAME=".htmlproject";
public MyCnfView() {
}
public IAdaptable getProjectInput(){
IWorkspaceRoot ws_root = ResourcesPlugin.getWorkspace().getRoot();
IProject proj = ws_root.getProject(PHANTOM_PROJECT_NAME);
if (!proj.exists()) return getSite().getPage().getInput();
return proj;
}
public void reset()
{
getCommonViewer().setInput(getProjectInput());
getCommonViewer().refresh();
}
@Override
protected IAdaptable getInitialInput() {
return getProjectInput();
}
}
- 將viewerContentBinding/includes的contentExtension的pattern替換為剛才定義的com.lifesting.cnf.directorycontent。
- 因為是Html Explorer，需要過濾掉非html文件，需要設置一個過濾器。通過extension point org.eclipse.ui.navigator.navigatorContent 新建一個id為com.lifesting.cnf.filter.nothtml的filter，它的class非常簡單：
public class NotHtmlFilter extends ViewerFilter {
public NotHtmlFilter() {
}
@Override
public boolean select(Viewer viewer, Object parentElement, Object element) {
if (element instanceof IFile)
{
return Util.isHtmlFile((IFile)element);
}
return true;
}
}
再將此filter配置到cnv的viewerContentBinding/includes中去，跟contentExtension配置過程一樣。
- 啟動后,cnv已經(jīng)可以工作，為了演示navigatorContent的可重復利用性，再定義一個只包含html文檔標題的html title content(為方便只掃描標題），掛在前面定義的directory content上。directory content的model是IProject/IFile/IFolder，html title content需要定義一個model，一個html文檔掃描器，還有contentPrvoider和lableProvider。
- model
public class HeadTitle {
private String title;
private IFile file;
private int from = 0;
public int getFrom() {
return from;
}
//略set/get
}
- scaner
public static HeadTitle parse(InputStream in) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(in));
int c = -1;
StringBuffer sb = new StringBuffer();
boolean tag = false;
boolean found_title = false;
String to_match = "title";
HeadTitle title = new HeadTitle();
int counter = 0;
int start = 0;
outer: while ((c = br.read()) != -1) {
if (c == '<') {
br.mark(3);
if (br.read() == '!' && br.read() == '-' && br.read() == '-') {
// loop over html comment until -->
counter += 3;
int t1, t2, t3;
t1 = t2 = t3 = 0;
while ((c = br.read()) != -1) {
t3 = t2;
t2 = t1;
t1 = c;
counter++;
if (t3 == '-' && t2 == '-' && t1 == '>') {
counter++; // '<' also need be countered
continue outer;
}
}
break outer; //reach the end
} else {
br.reset();
}
tag = true;
if (found_title) {
title.setTitle(sb.toString());
title.setFrom(start);
title.setTo(counter);
return title;
}
} else if (c == '>') {
start = counter + 1;
if (tag) {
String s = sb.toString().trim();
found_title = to_match.equalsIgnoreCase(s);
sb.setLength(0);
tag = false;
}
} else {
sb.append((char) c);
}
counter++;
}
title.setTitle("No title");
return title;
}
- contentProvider只有一個getChildren比較重要
private static final Object[] EMPTY = new Object[0];
@Override
public Object[] getChildren(Object parentElement) {
if (parentElement instanceof IFile)
{
IFile f = (IFile) parentElement;
if(Util.isHtmlFile(f))
{
try {
HeadTitle head = SimpleHtmlParser.parse(f.getContents());
head.setFile(f);
return new HeadTitle[]{head};
} catch (IOException e) {
e.printStackTrace();
} catch (CoreException e) {
e.printStackTrace();
}
}
}
return EMPTY;
}
- labelProivder
public class HtmlTitleLabelProvider extends LabelProvider {
public static final String KEY_TITLE_IMAGE="icon/title.GIF";
@Override
public String getText(Object element) {
if (element instanceof HeadTitle)
return ((HeadTitle)element).getTitle();
else if (element instanceof IFile)
return ((IFile)element).getName();
return super.getText(element);
}
@Override
public Image getImage(Object element) {
if (element instanceof HeadTitle)
{
Image img = Activator.getDefault().getImageRegistry().get(KEY_TITLE_IMAGE);
if (img == null)
{
Activator.getDefault().getImageRegistry().put(KEY_TITLE_IMAGE, (img = Activator.imageDescriptorFromPlugin(Activator.PLUGIN_ID, KEY_TITLE_IMAGE).createImage()));
}
return img;
}
return super.getImage(element);
}
}
- html title content利用directory content找到文件，提取標題，但二者有個東西來觸發(fā)這個過程。在html title content下定義個一個triggerPoints，使用instanceof=IFile來觸發(fā)。
- 所有的功能基本完成，剩下popmenu和link，popmenu可以有兩種方式, contribute或cnv下的popmenu子節(jié)點.contribute會在popmenu下建一堆比如group.*的menu placeholder。content下可以配置actionProvider來完成popmenu的功能，為簡單只在popmenu上放置一個open的動作，即open html file，如果是html file，直接打開；如果是html file title，還須將html title高亮顯示，以示不通，actionProivder:
public class MyCommonActionProvider extends CommonActionProvider {
private IAction action;
public MyCommonActionProvider() {
}
@Override
public void init(ICommonActionExtensionSite site) {
super.init(site);
ICommonViewerSite check_site = site.getViewSite();
if (check_site instanceof ICommonViewerWorkbenchSite)
{
ICommonViewerWorkbenchSite commonViewerWorkbenchSite = (ICommonViewerWorkbenchSite)check_site;
action = new OpenFileAction(commonViewerWorkbenchSite.getPage(),commonViewerWorkbenchSite.getSelectionProvider());
}
}
@Override
public void fillActionBars(IActionBars actionBars) {
super.fillActionBars(actionBars);
actionBars.setGlobalActionHandler(ICommonActionConstants.OPEN, action);
}
@Override
public void fillContextMenu(IMenuManager menu) {
super.fillContextMenu(menu);
if (action.isEnabled())
menu.appendToGroup("group.edit", action);
}
}
open file action:
public class OpenFileAction extends Action {
private IWorkbenchPage page;
private ISelectionProvider provider;
private Object selected = null;
public OpenFileAction(IWorkbenchPage page,
ISelectionProvider selectionProvider) {
this.page = page;
this.provider = selectionProvider;
setText("Open");
setDescription("Doo");
setImageDescriptor(Activator.imageDescriptorFromPlugin(Activator.PLUGIN_ID, "icon/lookin.GIF"));
}
@Override
public boolean isEnabled() {
ISelection selection = provider.getSelection();
if(!selection.isEmpty())
{
IStructuredSelection structuredSelection = (IStructuredSelection)selection;
Object element = structuredSelection.getFirstElement();
selected = element;
return element instanceof IFile || element instanceof HeadTitle;
}
selected = null;
return false;
}
@Override
public void run() {
if (null == selected) return ;
IFile file = ((selected instanceof HeadTitle) ? ((HeadTitle)selected).getFile() : (IFile)selected);
FileEditorInput fileEditInput = new FileEditorInput(file);
try {
TextEditor editor = (TextEditor) page.openEditor(fileEditInput, "org.eclipse.ui.DefaultTextEditor");
if (selected instanceof HeadTitle)
{
int from = ((HeadTitle)selected).getFrom();
int to = ((HeadTitle)selected).getTo();
editor.selectAndReveal(from, to-from);
}
} catch (PartInitException e) {
e.printStackTrace();
}
}
}
- Link功能非常簡單，使用extension point org.eclipse.ui.navigator.linkHelper，它有兩個子節(jié)點selectionEnablement和editorinputEnablement，分別對應在view中的selection和打開editor中的editorInput，class為：
public class SimpleHtmlLinkHelper implements ILinkHelper {
@Override
public void activateEditor(IWorkbenchPage page,
IStructuredSelection selection) {
Object obj = selection.getFirstElement();
if (obj instanceof IFile)
{
FileEditorInput input = new FileEditorInput((IFile) obj);
IEditorPart editor = page.findEditor(input);
if(editor != null)
{
page.bringToTop(editor);
}
}
}
@Override
public IStructuredSelection findSelection(IEditorInput anInput) {
if (anInput instanceof IFileEditorInput)
{
IFile file = ((IFileEditorInput)anInput).getFile();
StructuredSelection selection = new StructuredSelection(file);
return selection;
}
return null;
}
}
插件太復雜，不適合一篇blog講清楚，如果有人對cnv有些比明白，歡迎來郵件討論。