Difference between revisions of "Archive:Development/Tutorials/Session Management (zh CN)"

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==About KDE and X11 session management==
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==关于KDE和X11的会话管理==
  
Since KDE 1.0, the legacy X11R4 and ICCCM session management protocols
+
从KDE 1.0起,遗留的X11R4和ICCCM会话管理协议就被支持着。Legacy applications that define the <tt>WM_COMMAND</tt>
are supported. Legacy applications that define the <tt>WM_COMMAND</tt>
+
 
property or support the <tt>WM_SAVE_YOURSELF</tt> protocol will be restarted
 
property or support the <tt>WM_SAVE_YOURSELF</tt> protocol will be restarted
 
with the specified command.  The window geometries will be restored on a best
 
with the specified command.  The window geometries will be restored on a best
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danger to lose some data, and to cancel the shutdown process if necessary.
 
danger to lose some data, and to cancel the shutdown process if necessary.
  
==Further Reading==
+
==更多阅读==
  
 
An introductive overview of session management functionality and
 
An introductive overview of session management functionality and
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different user sessions.
 
different user sessions.
  
==Implementing session management in your application==
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==在你的应用中实现会话管理==
  
 
Here's just a brief overview how things are done. Again, see the
 
Here's just a brief overview how things are done. Again, see the
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That's all.
 
That's all.
  
===Reimplement some virtual functions of KMainWindow===
+
===重写KMainWindow的虚函数===
  
 
[http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html KMainWindow] will automatically save its position, geometry and positions of toolbars and menubar on logout - and restore it on the next startup.
 
[http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html KMainWindow] will automatically save its position, geometry and positions of toolbars and menubar on logout - and restore it on the next startup.
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''To save your application-wide properties (data that is only needed once per application, and not for each main window instance) reimplement [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#cf811d77a3acdcf2b61f8826429615a7 saveGlobalProperties()] and it's counterpart [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#2d4da4f305f00e8a5c94f5b978334231 readGlobalProperties].  Normally, you don't need these functions.''
 
''To save your application-wide properties (data that is only needed once per application, and not for each main window instance) reimplement [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#cf811d77a3acdcf2b61f8826429615a7 saveGlobalProperties()] and it's counterpart [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#2d4da4f305f00e8a5c94f5b978334231 readGlobalProperties].  Normally, you don't need these functions.''
  
===Add session management support to your main() function===
+
===给你的main()函数添加会话管理===
  
 
While [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#4c7a6c395eec0bb245cd9ad6c884f897 KMainWindow::saveProperties()] (and also [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#f8c5708414be62f259114b0453ef8432 KMainWindow::queryClose()]) will be called automatically, [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#c8d0d64ed5b309ba1da410423120d0a6 KMainWindow::readProperties()] will not. You have to add some code to your main() function to implement session restoring.
 
While [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#4c7a6c395eec0bb245cd9ad6c884f897 KMainWindow::saveProperties()] (and also [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#f8c5708414be62f259114b0453ef8432 KMainWindow::queryClose()]) will be called automatically, [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#c8d0d64ed5b309ba1da410423120d0a6 KMainWindow::readProperties()] will not. You have to add some code to your main() function to implement session restoring.
  
Imagine you have an
+
如果你的应用有一个主窗口,MyWindow,他继承与
application with a main window MyWindow inherited from
+
[http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html KMainWindow] (或从
[http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html KMainWindow] (or from
+
[http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKXmlGuiWindow.html KXmlGuiWindow], 他继承于
[http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKXmlGuiWindow.html KXmlGuiWindow], which inherits from
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[http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html KMainWindow])。在你的main()函数内,要加上下列代码来创建/恢复窗口:
[http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html KMainWindow]). In your main() function, you would then create/restore the
+
application windows with something like this:
+
  
 
<code cppqt>
 
<code cppqt>
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[http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/kmainwindow_8h.html#88ce427e39f425eefa5a94d746eb2bed kRestoreMainWindows<>()] will create (on the heap) as many instances of your main windows as have existed in the last session and call [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#46e01bd1aa6d488f1be2a5010030efb2 KMainWindow::restore()] with the correct arguments. Note that also QWidget::show() is called implicitly.
 
[http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/kmainwindow_8h.html#88ce427e39f425eefa5a94d746eb2bed kRestoreMainWindows<>()] will create (on the heap) as many instances of your main windows as have existed in the last session and call [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/classKMainWindow.html#46e01bd1aa6d488f1be2a5010030efb2 KMainWindow::restore()] with the correct arguments. Note that also QWidget::show() is called implicitly.
  
About setObjectName("MyWindow#"): For session management and window management to work properly, all main windows in the application should have a different name. If you don't do it, KMainWindow will create a unique name, but it's recommended to explicitly pass a window name that will also describe the type of the window. If there can be several windows of the same type, append '#' (hash) to the name, and KMainWindow will replace it with numbers to make the names unique. For example, for a mail client which has one main window showing the mails and folders, and which can also have one or more windows for composing mails, the name for the folders window should be e.g. "mainwindow" and for the composer windows "composer#".
+
关于setObjectName("MyWindow#"): For session management and window management to work properly, all main windows in the application should have a different name. If you don't do it, KMainWindow will create a unique name, but it's recommended to explicitly pass a window name that will also describe the type of the window. If there can be several windows of the same type, append '#' (hash) to the name, and KMainWindow will replace it with numbers to make the names unique. For example, for a mail client which has one main window showing the mails and folders, and which can also have one or more windows for composing mails, the name for the folders window should be e.g. "mainwindow" and for the composer windows "composer#".
  
 
With this you can easily restore all toplevel windows of your application.
 
With this you can easily restore all toplevel windows of your application.
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Currently, the [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/kmainwindow_8h.html#88ce427e39f425eefa5a94d746eb2bed kRestoreMainWindows<>()] template functions are provided for up to three template arguments.
 
Currently, the [http://api.kde.org/4.x-api/kdelibs-apidocs/kdeui/html/kmainwindow_8h.html#88ce427e39f425eefa5a94d746eb2bed kRestoreMainWindows<>()] template functions are provided for up to three template arguments.
  
==Appendix: Architecture of the KDE session manager==
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==附录: KDE会话管理的架构==
  
 
The session management server in KDE is called '''ksmserver''' and it is
 
The session management server in KDE is called '''ksmserver''' and it is
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''Initial Author:'' [mailto:ettrich@kde.org Matthias Ettrich]
+
''初始作者:'' [mailto:ettrich@kde.org Matthias Ettrich]
  
 
[[Category:Programming]]
 
[[Category:Programming]]
 
[[Category:Tutorial]]
 
[[Category:Tutorial]]
 
[[Category:FAQs]]
 
[[Category:FAQs]]

Revision as of 09:45, 14 September 2009


Contents

Development/Tutorials/Session Management


Template:TutorialBrowser (zh CN)

关于KDE和X11的会话管理

从KDE 1.0起,遗留的X11R4和ICCCM会话管理协议就被支持着。Legacy applications that define the WM_COMMAND property or support the WM_SAVE_YOURSELF protocol will be restarted with the specified command. The window geometries will be restored on a best effort basis.

Since KDE 2.0, also the standard X11R6 session management protocol XSMP is supported and used. The official documentation of the standard can be download from the X Consortium's FTP server ftp.x.org. Unlike the legacy protocols, the new X11R6 session management gives a chance to save application dependent settings when you log out. A text editor, for instance, would save the names of the loaded files and would reload them when you log in again. Another major advantage of the new protocol is the support for a clean and safe logout procedure even if the users decides not to restore the session next time. The protocol gives applications the possibility to interact with the user in case they are in danger to lose some data, and to cancel the shutdown process if necessary.

更多阅读

An introductive overview of session management functionality and the Qt API for it is available from doc.trolltech.com.

In KDE, the classes KApplication and KMainWindow hide all the ugly details from the programmer. Basically, a KApplication manages a KConfig configuration object (available trought KApplication::sessionConfig()) for you, that your application can utilize to store session specific data.

Please read the respective class documentation, especially the one of KMainWindow, for a detailed interface description. With the advanced functionality in KMainWindow, it's really just a matter of a few lines to get even a multi-window application to retains its state between different user sessions.

在你的应用中实现会话管理

Here's just a brief overview how things are done. Again, see the respective class documentation for details.

Implementing session management in KDE is easy. If your main window inherits from KMainWindow, you have just 2 things to do:

  • Reimplement some virtual functions of KMainWindow.
  • Add session management support to your main() function.

That's all.

重写KMainWindow的虚函数

KMainWindow will automatically save its position, geometry and positions of toolbars and menubar on logout - and restore it on the next startup.

For every other data that your application needs to restore a session, you have to write the code for saving and restoring yourself. However, KMainWindow makes this task easy. You can just re-implement the following functions:

  • saveProperties(): This function is called only when the application is closed by the session manager (and not, when the application is closed by the user). To save the data that you need to restore the session, reimplement this function. (For a text editor for example, that would be the list of loaded files) Note that no user interaction is allowed in this function! (For example, you may not display any dialog!)
  • readProperties(): To read the additional data again on next login, reimplement this function.

Furthermore, the function queryClose() could be interesting for you. This function is called always before the window is closed, either by the user or indirectly by the session manager. Typically, here you can warn the user that the application or some windows have unsaved data on close or logout (for example: show a dialog with the buttons "Save changes" and "Discard changes"). However, for session management it isn't nice to request a user interaction before closing, so you better avoid this. Note that it is not determined if saveProperties() is called before or after queryClose()!

To save your application-wide properties (data that is only needed once per application, and not for each main window instance) reimplement saveGlobalProperties() and it's counterpart readGlobalProperties. Normally, you don't need these functions.

给你的main()函数添加会话管理

While KMainWindow::saveProperties() (and also KMainWindow::queryClose()) will be called automatically, KMainWindow::readProperties() will not. You have to add some code to your main() function to implement session restoring.

如果你的应用有一个主窗口,MyWindow,他继承与 KMainWindow (或从 KXmlGuiWindow, 他继承于 KMainWindow)。在你的main()函数内,要加上下列代码来创建/恢复窗口:

KApplication app; if ( app.isSessionRestored() ) {

 kRestoreMainWindows< MyWindow >();

} else {

 // create default application as usual
 // for example:
 MyWindow * window = new MyWindow();
 // # will be replaced with numbers that are guaranteed
 // to be unique in the application:
 window->setObjectName("MyWindow#");
 window->show();

} return app.exec();

kRestoreMainWindows<>() will create (on the heap) as many instances of your main windows as have existed in the last session and call KMainWindow::restore() with the correct arguments. Note that also QWidget::show() is called implicitly.

关于setObjectName("MyWindow#"): For session management and window management to work properly, all main windows in the application should have a different name. If you don't do it, KMainWindow will create a unique name, but it's recommended to explicitly pass a window name that will also describe the type of the window. If there can be several windows of the same type, append '#' (hash) to the name, and KMainWindow will replace it with numbers to make the names unique. For example, for a mail client which has one main window showing the mails and folders, and which can also have one or more windows for composing mails, the name for the folders window should be e.g. "mainwindow" and for the composer windows "composer#".

With this you can easily restore all toplevel windows of your application.

It is also possible to restore different types of toplevel windows (each derived from KMainWindow, of course) within one application. Imagine you have three classes of main windows: childMW1, childMW2 and childMW3:

KApplication app; if ( app.isSessionRestored() ) {

 kRestoreMainWindows< childMW1, childMW2, childMW3 >();

} else {

 // create default application as usual
 // for example:
 childMW1* window1 = new childMW1();
 childMW2* window2 = new childMW2();
 childMW3* window3 = new childMW3();
 // # will be replaced with numbers that are guaranteed
 // to be unique in the application:
 window1->setObjectName("type1mainWindow#");
 window2->setObjectName("type2mainWindow#");
 window3->setObjectName("type3mainWindow#");
 window1->show();
 window2->show();
 window3->show();

} return app.exec();

Currently, the kRestoreMainWindows<>() template functions are provided for up to three template arguments.

附录: KDE会话管理的架构

The session management server in KDE is called ksmserver and it is part of the kdebase package. The server interacts with the KDE window manager kwin to save and restore the window geometries and to perform legacy session management. To make session management work, ksmserver has to be started as last process of the X login procedure. This happens automatically at the end of the startkde script.


初始作者: Matthias Ettrich


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