Tutorial: Create Login Dialog for your Eclipse E4 Application

Environment Setup and Source Code

As prerequisite we will need to get Eclipse SDK and add the E4 Tools.

• in this tutorial we use Eclipse IDE for Eclipse Committers 4.5.0 M5 plus the E4 Tools I20150105-1100.
• The source code for this examples is in project com.asegno.e4app.first , clonable from https://github.com/psuzzi/asegno.git repo.

Create an E4 RCP Application

CTRL+N > type “4” , select Eclipse 4 Application Project, click Next.

Type com.asegno.e4app.first as Project Name, keep defaults and press Next

Check “Generate an activator ..” , keep other defaults and press Next.

Check “Add a lifecycle class”, keep other defaults and click Finish.

Launch the application from the product file to check it can run.

Edit the @PostContextCreate method in the E4 Lifecycle class

 /**
  * Note : the model has not been loaded at this point 
  */
 @PostContextCreate
 void postContextCreate(IEclipseContext workbenchContext) {
 
 final Shell shell = new Shell(SWT.TOOL|SWT.NO_TRIM);
 LoginDialog dialog = new LoginDialog(shell);
 if(dialog.open() != Window.OK){
 // close application
 System.exit(-1);
 }
 
 // continue to the initial window
 }

Then add a LoginDialog class as follows

public class LoginDialog extends TitleAreaDialog {

 // Widgets
 private Text textUsername;
 private Text textPassword;

 @Inject
 MApplication application;

 public LoginDialog(Shell parentShell) {
 super(parentShell);
 }

 @Override
 protected Control createContents(Composite parent) {
 Control contents = super.createContents(parent);
 setTitle("Login");
 setMessage("Please provide credentials");
 return contents;
 }

 @Override
 protected Control createDialogArea(Composite parent) {
 Composite area = (Composite) super.createDialogArea(parent);

 System.out.println(application);

 Composite container = new Composite(area, SWT.NULL);
 container.setLayout(new GridLayout(2, false));
 container.setLayoutData(new GridData(GridData.FILL_BOTH));

 new Label(container, SWT.NULL).setText("Username");
 textUsername = new Text(container, SWT.BORDER);
 textUsername.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));

 new Label(container, SWT.NULL).setText("Password");
 textPassword = new Text(container, SWT.PASSWORD | SWT.BORDER);
 textPassword.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));

 return area;
 }

 @Override
 protected Point getInitialSize() {
 return new Point(500, 300);
 }

}

If you launch the application you’ll see the the System.out.println(application) will print null. This is because the LoginDialog is launched @PostContextCreate, when the model is not yet loaded.

But, if you open the dialog in the @ProcessAdditions, and you invoke the ContextInjectionFactory.inject(dialog, workbenchContext); before opening the dialog, you’ll see the application is not null anymore. Therefore edit the two methods, as below

 @PostContextCreate
 void postContextCreate(IEclipseContext workbenchContext) {
 }

 /** ... */

 @ProcessAdditions
 void processAdditions(IEclipseContext workbenchContext) {
 final Shell shell = new Shell(SWT.TOOL|SWT.NO_TRIM);
 LoginDialog dialog = new LoginDialog(shell);
 ContextInjectionFactory.inject(dialog, workbenchContext);
 if(dialog.open() != Window.OK){
 // close application
 System.exit(-1);
 }
 
 // continue to the initial window
 }

So, we’re going to add an hook to the APP_STARTUP_COMPLETE for getting isntances of Application’s object and services.

First, add plugins needed to use the event framework

• org.eclipse.e4.core.services
• org.eclipse.osgi.services

 References

• Kai Toeder on lifecycle hooks
• Eclipse Bugzilla’s bug 376821
• Eclipse Forum on login dialog and lifecycle
• Vogella on E4 Event System