需要以下的對象：
LoginDialog，用于展示狀態，
LoginListener，用于監聽登錄狀態，并根據不同的情況改變LoginDialog的顯示
LoginAction，用于執行登錄的業務邏輯，并且根據不同的結果來fire不同的動作。
狀態一共有以下幾種：
1。登錄中
2。登錄成功
3。登錄失敗
? 3.1 連接失敗
? 3.2 用戶名密碼錯誤
? 3.3 .....
4。用戶取消登錄
下面是代碼片段：
Application；
public?class?Application?implements?IPlatformRunnable?{
? ???
????/*
?????*?(non-Javadoc)
?????*?
?????*?@see?org.eclipse.core.runtime.IPlatformRunnable#run(java.lang.Object)
?????*/
????public?Object?run(Object?args)?throws?Exception?{
????????try?{
????????????TestLoginDialog?dialog?=?new?TestLoginDialog(Display.getCurrent()
????????????????????.getActiveShell());
????????????LoginListener?loginListener?=?new?LoginListenerImpl(dialog);
????????????LoginAction?action?=?new?LoginAction("login");
????????????action.addLoginListener(loginListener);
????????????dialog.setLoginAction(action);
????????????if?(dialog.open()?!=?Window.OK)?{
????????????????return?IPlatformRunnable.EXIT_OK;
????????????}
????????????int?returnCode?=?PlatformUI.createAndRunWorkbench(display,
????????????????????new?ApplicationWorkbenchAdvisor());
????????????if?(returnCode?==?PlatformUI.RETURN_RESTART)?{
????????????????return?IPlatformRunnable.EXIT_RESTART;
????????????}
????????????return?IPlatformRunnable.EXIT_OK;
????????}?finally?{
????????????display.dispose();
????????}
????}
}
LoginListener：
public?interface?LoginListener?extends?EventListener{
????public?void?loginError(String?message);
????public?void?loginComplete();
????public?void?loginCanceled();
????
????public?void?loginStarted();
????
}
LoginAction：這里要用到Job，因為登錄的邏輯處理必須要在異步線程中來做，否則UI就會停住的。
public?class?LoginAction?extends?Job?{
????private?LoginListener?loginListener;
????private?Session?session?=?Session.getInstance();
????public?LoginAction(String?name)?{
????????super(name);
????}
????public?void?addLoginListener(LoginListener?listener)?{
????????this.loginListener?=?listener;
????}
????public?void?fireLoginComplete()?{
????????loginListener.loginComplete();
????}
????public?void?fireLoginStarted()?{
????????loginListener.loginStarted();
????}
????public?void?fireLoginError(String?message)?{
????????loginListener.loginError(message);
????}
????public?void?fireLoginCanceled()?{
??? ??? //write cancel login logic here
????????loginListener.loginCanceled();
????}
????@Override
????protected?IStatus?run(IProgressMonitor?monitor)?{
????????login();
????????return?Status.OK_STATUS;
????}
????public?boolean?login()?{
????????fireLoginStarted();
????????if?(//網絡連接失敗)?{
??????????? fireLoginError(Messages.getString("Session.connectionFailed"));
????????}?else?{
????????????if?(//登錄失敗)?{
??????????? fireLoginError(Messages.getString("Session.loginFailed"));
????????????}?else?{
????????????????session.setAuthenticated(true);
????????????????fireLoginComplete();
??? ??? ??? ??? //處理登錄動作
????????????}
????????}
????????return?session.isAuthenticated();
????}
}
LoginDialog：
這里用到了StackLayout，因為在登錄的過程中，需要在顯示用戶名/密碼的位置上，顯示gif動畫，所以在createDialogArea的時候，要創建一個主Composite，然后將其layout設置為StackLayout，然后創建兩個Composite，將其parent都設置為主Composite，新創建的兩個我將其命名為loginInfoComposite和loginAnimaComposite，顧名思義，一個用來顯示登錄信息，一個用來顯示登錄動畫。
關于如何顯示gif，我在這里就不多說了，因為SWT Snippet和Eclipse的SWT Example里面都有對應的例子，我在這里推薦大家去參考一下SWT Example，因為那里面是用Canvas來繪圖的，這也是我們所需要的。
在使用StackLayout的時候要注意，當我們使用stackLayout.topControl = xxx的時候，還要調用stackLayout.layout()方法，否則會不起作用。
還有就是因為在登錄的過程中，按鈕欄應該是不可見的，但是Dialog的getButtonBar方法是protected的，所以就重寫了這個方法，聲明為public，返回super.getButtonBar()，雖然源碼的注釋中寫著這個方法不應該重寫，但是我想，這樣子應該沒問題吧。
另外，在繪制gif的下方添加一個按鈕，并且addSelectionListener，當SelectionEvent發生的時候，就去觸發loginAction的fireCancel方法就可以了。
細節就不描述了，下面是一些個人認為比較關鍵的代碼片段：
????/*
?????*?to?create?login?button?
?????*/
????public?static?int?LOGIN_ID?=?9527;
????protected?void?createButtonsForButtonBar(Composite?parent)?{
????????createButton(parent,?LOGIN_ID,?Messages
????????????????.getString("LoginDialog.loginbutton"),?true);?]
????????createButton(parent,?IDialogConstants.CANCEL_ID,?Messages
????????????????.getString("LoginDialog.cancelbutton"),?false);
????}
????@Override
????protected?void?buttonPressed(int?buttonId)?{
????????if?(buttonId?==?LOGIN_ID)?{
????????????loginPressed();
????????}
????????super.buttonPressed(buttonId);
????}
??? protected?void?loginPressed()?{
??? ??? //...
????????loginAction.schedule();
????}
然后是LoginListener的實現類：
public?class?LoginListenerImpl?implements?LoginListener?{
????private?Display?display;
????//login?dialog
????private?TestLoginDialog?dialog;
????//image?to?show?on?login?failed
????private?Image?errorMessageImage?=?AbstractUIPlugin
????????????.imageDescriptorFromPlugin(Application.PLUGIN_ID,
????????????????????IImageKeys.crodoTitleImage).createImage();
????//error?message?area?background
????private?Color?errorMessageBackground?=?new?Color(null,?255,?255,?0);
????public?LoginListenerImpl(TestLoginDialog?dialog)?{
????????this.dialog?=?dialog;
????????display?=?Display.getCurrent();
????}
??? //因為這里需要在非UI線程中更新UI，所以要用display.syncExec()方法。
????public?void?loginCanceled()?{
????????display.syncExec(new?Runnable()?{
????????????public?void?run()?{
????????????????dialog.getStackLayout().topControl?=?dialog
????????????????????????.getLoginInfoComposite();
????????????????dialog.getStackLayoutComposite().layout();
????????????????dialog.animate();
????????????????dialog.getButtonBar().setVisible(true);
????????????}
????????});
????}
????public?void?loginComplete()?{
????????display.syncExec(new?Runnable()?{
????????????@SuppressWarnings("deprecation")
????????????public?void?run()?{
??? ??? ??? ??? //我知道Thread.stop()方法已經被廢棄，但是暫時沒想到什么方法來中止
??? ??? ??? ??? //就暫時這樣子用了，還請大家指教！
????????????????dialog.getAnimateThread().stop();
????????????????dialog.okPressed();
????????????}
????????});
????}
????public?void?loginError(final?String?message)?{
????????display.syncExec(new?Runnable()?{
????????????public?void?run()?{
????????????????dialog.getErrorMessageLabel().setText(message);
????????????????dialog.getErrorMessageLabel().setImage(errorMessageImage);
????????????????dialog.getErrorMessageLabel().setBackground(
????????????????????????errorMessageBackground);
????????????????dialog.getStackLayout().topControl?=?dialog
????????????????????????.getLoginInfoComposite();
????????????????dialog.getStackLayoutComposite().layout();
????????????????dialog.animate();
????????????????dialog.getButtonBar().setVisible(true);
????????????}
????????});
????}
????public?void?loginStarted()?{
????????display.syncExec(new?Runnable()?{
????????????public?void?run()?{
????????????????dialog.getStackLayout().topControl?=?dialog
????????????????????????.getLoginAnimaComposite();
????????????????dialog.getStackLayoutComposite().layout();
????????????????dialog.animate();
????????????????dialog.getButtonBar().setVisible(false);
????????????}
????????});
????}