[英]I am trying to make Restful Webservice and it's client,facing issue while passing XML
[英]I am facing error “NullPointExeption”, while trying to detect the user's selection in the eclipse plugin development
我在尝试在eclipse插件开发中检测用户的选择时遇到错误“ NullPointExeption”。 我已经附上了两个类的代码,首先是DetectSelection,它检测项目浏览器中的用户选择,其次,是SampleView,它使自定义插件
我之前问过的问题: Eclipse插件:在用户单击/选择时获取类名
之后,它可以正常工作,但是现在我又遇到了一些错误:现在,我创建了DetectSelection类:
public class DetectSelection
{
String classname ;
IPath packageName ;
private ISelection selection;
public void setSelection(ISelection iSelection)
{
this.selection = iSelection;
}
public void jk()
{
System.out.println(" HI!!!!");
IWorkbenchPage page =PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
IViewPart viewPart = page.findView("org.eclipse.jdt.ui.PackageExplorer");
ISelectionProvider selProvider = viewPart.getSite().getSelectionProvider();
selProvider.addSelectionChangedListener(new ISelectionChangedListener()
{
public void selectionChanged(SelectionChangedEvent event)
{
if (!event.getSelection().isEmpty())
{
Iterator ite = ((IStructuredSelection) event.getSelection()).iterator();
while (ite.hasNext())
{
Object obj = ite.next();
String testString="";
if (obj instanceof IJavaElement)
{
packageName= ((IJavaElement)obj).getPath();
System.out.println("getFileExtension() "+ packageName.getFileExtension() );
String s= packageName.toString();
String s1[]= s.split("/");
if ("java".equals(packageName.getFileExtension()))
{
System.out.println("package name "+ s1[1]);
System.out.println("project name"+ ((IJavaElement)obj).getElementName());
}
}
}
}
}
});
}
}
以前,当我在SampleView类中创建此对象并像这样使用它时,这种方法就可以正常工作:
public class SampleView extends ViewPart
{
public static final String ID = "typesview.views.SampleView";
private TableViewer viewer;
private Action action1;
private Action action2;
private Action doubleClickAction;
class ViewContentProvider implements IStructuredContentProvider
{
public void inputChanged(Viewer v, Object oldInput, Object newInput)
{
}
public void dispose()
{
}
public Object[] getElements(Object parent)
{
return new String[] { "One", "Two", "Three" };
}
}
class ViewLabelProvider extends LabelProvider implements ITableLabelProvider {
public String getColumnText(Object obj, int index) {
return getText(obj);
}
public Image getColumnImage(Object obj, int index) {
return getImage(obj);
}
public Image getImage(Object obj) {
return PlatformUI.getWorkbench().
getSharedImages().getImage(ISharedImages.IMG_OBJ_ELEMENT);
}
}
class NameSorter extends ViewerSorter {
}
public SampleView() {
}
public void createPartControl(Composite parent) {
**DetectSelection obj2 = new DetectSelection();
obj2.jk();**
viewer = new TableViewer(parent, SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL);
viewer.setContentProvider(new ViewContentProvider());
viewer.setLabelProvider(new ViewLabelProvider());
viewer.setSorter(new NameSorter());
viewer.setInput(getViewSite());
PlatformUI.getWorkbench().getHelpSystem().setHelp(viewer.getControl(), "TYPESview.viewer");
makeActions();
hookContextMenu();
hookDoubleClickAction();
contributeToActionBars();
}
private void hookContextMenu() {
MenuManager menuMgr = new MenuManager("#PopupMenu");
menuMgr.setRemoveAllWhenShown(true);
menuMgr.addMenuListener(new IMenuListener() {
public void menuAboutToShow(IMenuManager manager) {
SampleView.this.fillContextMenu(manager);
}
});
Menu menu = menuMgr.createContextMenu(viewer.getControl());
viewer.getControl().setMenu(menu);
getSite().registerContextMenu(menuMgr, viewer);
}
private void contributeToActionBars() {
IActionBars bars = getViewSite().getActionBars();
fillLocalPullDown(bars.getMenuManager());
fillLocalToolBar(bars.getToolBarManager());
}
private void fillLocalPullDown(IMenuManager manager) {
manager.add(action1);
manager.add(new Separator());
manager.add(action2);
}
private void fillContextMenu(IMenuManager manager) {
manager.add(action1);
manager.add(action2);
manager.add(new Separator(IWorkbenchActionConstants.MB_ADDITIONS));
}
private void fillLocalToolBar(IToolBarManager manager) {
manager.add(action1);
manager.add(action2);
}
private void makeActions() {
action1 = new Action() {
public void run() {
showMessage("Action 1 executed");
}
};
action1.setText("Action 1");
action1.setToolTipText("Action 1 tooltip");
action1.setImageDescriptor(PlatformUI.getWorkbench().getSharedImages().
getImageDescriptor(ISharedImages.IMG_OBJS_INFO_TSK));
action2 = new Action() {
public void run() {
showMessage("Action 2 executed");
}
};
action2.setText("Action 2");
action2.setToolTipText("Action 2 tooltip");
action2.setImageDescriptor(PlatformUI.getWorkbench().getSharedImages().
getImageDescriptor(ISharedImages.IMG_OBJS_INFO_TSK));
doubleClickAction = new Action() {
public void run() {
ISelection selection = viewer.getSelection();
Object obj = ((IStructuredSelection)selection).getFirstElement();
showMessage("Double-click detected on "+obj.toString());
}
};
}
private void hookDoubleClickAction() {
viewer.addDoubleClickListener(new IDoubleClickListener() {
public void doubleClick(DoubleClickEvent event) {
doubleClickAction.run();
}
});
}
private void showMessage(String message) {
MessageDialog.openInformation(
viewer.getControl().getShell(),
"Sample View",
message);
}
public void setFocus() {
viewer.getControl().setFocus();
}
}
现在,在运行插件时,出现错误:
java.lang.NullPointerException
at typesview.views.DetectSelection.jk(DetectSelection.java:40)
at typesview.views.SampleView.createPartControl(SampleView.java:58)
at org.eclipse.ui.internal.ViewReference.createPartHelper(ViewReference.java:375)
at org.eclipse.ui.internal.ViewReference.createPart(ViewReference.java:229)
at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:595)
at org.eclipse.ui.internal.WorkbenchPage$ActivationList.setActive(WorkbenchPage.java:4317)
at org.eclipse.ui.internal.WorkbenchPage$18.runWithException(WorkbenchPage.java:3359)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4140)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3757)
at org.eclipse.ui.application.WorkbenchAdvisor.openWindows(WorkbenchAdvisor.java:803)
at org.eclipse.ui.internal.Workbench$33.runWithException(Workbench.java:1600)
at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4140)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3757)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2609)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2499)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:679)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:668)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
at org.eclipse.equinox.launcher.Main.main(Main.java:1386)
图片获取行号:
DetectSelection:
SampleView:
stacktrace和屏幕截图中的行号未正确对齐。
但是实际上,无论如何,只能由jk
方法的前五行抛出异常。 (其余的定义了一个回调方法/对象,如果该代码抛出了NPE,则堆栈跟踪中的类名将有所不同。)
我建议您添加更多的跟踪记录,或使用调试器找出哪条语句实际上引发了异常...并向后返回null
的源。
该方法的javadoc说:
返回此页面中具有指定ID的视图。 页面中最多有一个具有指定ID的视图。
返回:视图;如果未找到,则返回null
如果从原因中得到null
,则说明id参数不正确。
这可能相关,也可能无关,但是您正在传递"org.eclipse.jdt.ui.PackageExplorer"
来find
,但是SampleView
类的ID
是"typesview.views.SampleView"
。
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