在Eclipse插件中将文件打开到特定行

Question

I am writting a plugin that has to open a file at a certain line when a button is pressed. I have the following code to open the file at a certain line.

        String filePath = "file path" ;
            final IFile inputFile = ResourcesPlugin.getWorkspace().getRoot().getFileForLocation(Path.fromOSString(filePath));
            if (inputFile != null) {
                IWorkbenchPage page1 = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
                IEditorPart openEditor11 = IDE.openEditor(page1, inputFile);
            }


            int Line = 20;

                    if (openEditor11 instanceof ITextEditor) {
                        ITextEditor textEditor = (ITextEditor) openEditor ;
                        IDocument document= textEditor.getDocumentProvider().getDocument(textEditor.getEditorInput());
                        textEditor.selectAndReveal(document.getLineOffset(Line - 1), document.getLineLength(Line-1));
                    }

My problem is that the variable openEditor11 in the if statement gives the error: openEditor11 cannot be resolved to a variable. What can be the problem ?

Answer 1

That's because the declaration of the variable, nested inside an if statement goes out of scope when finishing the condition. Therefore the variable is freed, and in your second statement, doesn't exist anymore.

You should declare it previously to circumvent this error like this :

IEditorPart openEditor11;
String filePath = "file path" ;
final IFile inputFile = ResourcesPlugin.getWorkspace().getRoot().getFileForLocation(Path.fromOSString(filePath));
if (inputFile != null) {
    IWorkbenchPage page1 = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
    openEditor11 = IDE.openEditor(page1, inputFile);
}


int Line = 20;

if (openEditor11 instanceof ITextEditor) {
    ITextEditor textEditor = (ITextEditor) openEditor ;
    IDocument document= textEditor.getDocumentProvider().getDocument(textEditor.getEditorInput());
    textEditor.selectAndReveal(document.getLineOffset(Line - 1), document.getLineLength(Line-1));
}

Reaching the second condition block, the editor might be null, if first condition didn't apply, but this is not a problem, since instanceof return false on nulls.

Answer 2

There is actually a more straightforward solution as per https://wiki.eclipse.org/FAQ_How_do_I_open_an_editor_on_a_file_in_the_workspace%3F

int lineNumber = ...
IPath path = ...
IFile file = ResourcesPlugin.getWorkspace().getRoot().getFile(path);
IMarker marker = file.createMarker(IMarker.TEXT);
marker.setAttribute(IMarker.LINE_NUMBER, lineNumber);
IWorkbenchPage page = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
IDE.openEditor(page, marker);
marker.delete();