Archive:Development/Languages/Ruby (zh CN)

Development/Languages/Ruby

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非常完整的绑定包括 KDE API 和 Qt API。Korundum 套件包括 QtRuby，以及完整结合 Qt/KDE。QtRuby 套件仅包含 Qt 绑定并不相依 KDE。

Korundum/QtRuby - Ruby-KDE/Qt 绑定

Rapid GUI Development with QtRuby (使用Qt 3.x)已经出版。

作为基于 Smoke 的绑定，意味着他们提供完整使用大多数 KDE 4.x 和Qt 4.x类.

QtRuby

Hello world例子:

1. !/usr/bin/ruby -w

require 'Qt4' a = Qt::Application.new(ARGV) hello = Qt::PushButton.new("Hello World!") hello.resize(100, 30) hello.show a.exec

Hello Qt例子；更 'Rubyish'的方式：

require 'Qt4'

Qt::Application.new(ARGV) do

   Qt::Widget.new do

       self.window_title = 'Hello QtRuby v1.0'
       resize(200, 100)
   
       button = Qt::PushButton.new('Quit') do
           connect(SIGNAL :clicked) { Qt::Application.instance.quit }
       end

       label = Qt::Label.new('Hello Qt in the Ruby way!')
       
       self.layout = Qt::VBoxLayout.new do
           add_widget(label, 0, Qt::AlignCenter)
           add_widget(button, 0, Qt::AlignRight)
       end
       
       show
   end
   
   exec

end

当前 API覆盖率一览

可用调用

你可以呼叫 Qt 所有的公用（public）和保护（protected）方法，以及所有 friend 方法，如bitBlt() 等

虚方法

所有的虚拟方法都可以被覆盖，不仅仅是事件处理

配置属性

「foobar = 5」是「setFooBar(5)」的同义词

使用 CamelCase 或小写加底线的名称都可以

在方法的命名中任何底线被取消，而接续的字符大写化。例如，您可以使用这两种形式来呼叫相同的方法：

      create_standard_status_bar_action()
      createStandardStatusBarAction()

操作符重载

Qt 所有的操作符方法皆可用，例如：

      p1 = Qt::Point.new(5,5)   => (5, 5)
      p2 = Qt::Point.new(20,20) => (20, 20)
      p1 + p2                   => (25, 25)

声明信号和槽（Signals和Slot）

讯号和槽宣告为如下的字符串列表：

      slots 'setColor(QColor)', 'slotLoad(const QString&)'..
      signals 'clicked()'..

对于槽和不带参数讯号，你可以使用 Ruby 符号：

      slots :slotLoad
      signals :clicked
       

Currently C++ type signatures must be used, a future version of QtRuby will allow ruby type signatures instead.

像这样连接（connect）槽和讯号：

      Qt::Object.connect( @colormenu, SIGNAL( "activated(int)" ),
                        self, SLOT( "slotColorMenu(int)" ) )

或者，您可以连接讯号到区块：

      quit_button.connect(SIGNAL :clicked) { $qApp.quit }

和这样发出（emit）讯号：

      emit colorChanged( black )

构造器

你可以用普通风格呼叫建构子：

      quit = Qt::PushButton.new("Quit", self, "quit")

或者，您可以传递区块，如果你喜欢的话：

      w = MyWidget.new { setCaption("foobar") }

The block will be called in the context of the newly created instance.

Ordinary arguments can be provided as well as a block at the end:

      w = MyWidget.new(nil) { setCaption("foobar") }

They are run in the context of the new instance.

And there's more! You can also pass an arg to the block, and it will be run in the context of the arg:

      w = MyWidget.new { |theWidget| theWidget.setCaption "foobar" }

垃圾回收

当 ruby 实例垃圾回收时，如果不是被父对象「拥有」，基本的 C++ 实例只会删除。通常这会「正常运作」，但有时您需要在垃圾回收之前删除 C++，不管它是否有父亲。使用 dispose()、isDisposed() 和 disposed? 方法像是这样：

      item2.dispose
      if item2.disposed?
      	puts "item2 is disposed"
      end

C++ 'int*' 和 'int&' 参数类型

Ruby passes numeric values by value, and so they can't be changed when passed to a method. The Qt::Integer class provides a mutable numeric type which does get updated when passed as an argument. For example, this C++ method 'findByFileContent()':

      # static Ptr findByFileContent( const QString &fileName, 
      #                               int *accuracy=0 );

      acc = Qt::Integer.new(0)
      fc = KDE::MimeType.findByFileContent("mimetype.rb", acc)

It supports the arithmetic operators, and so expressions such as 'acc + 3' will work.

C++ 'bool*' 和 'bool&' 参数类型

There is a similar problem for bool arg types, and the mutable Qt::Boolean class can be used like this:

      # QFont getFont(bool * ok, const QFont&initial, 
      #               QWidget* parent = 0, const char *name = 0);		
		
      ok = Qt::Boolean.new
      font = Qt::FontDialog.getFont(ok, 
                          Qt::Font.new("Helvetica [Cronyx]", 10), 
                          self)
      if !ok.nil? 
      	# font is set to the font the user selected
      else 
      	# the user canceled the dialog
      end

Use 'nil?' to test the value returned in the Boolean

C++ (const )(unsigned )char* 参数类型

In some cases Qt/KDE object "takes ownership" over Ruby String passed as char* argument type. Programmer needs to make sure that Ruby String is not being garbage collected or changed for the time it's being used by Qt/KDE object. It is also quite possible that Qt/KDE object will change and eventually free it(memory used internally by Ruby String to store its data). Be very careful when you call this kind of methods and make sure that there is no overloaded version witch accepts QString or QByteArray first!

C++ unsigned char* functions

Very few functions (as QImage::bits()) return a uchar* to directly manipulate data. These functions are not supported in Ruby and will throw an ArgumentError. More information on the mail list.

调试

If a method call can't be matched in the Smoke library giving a 'method_missing' error, you can turn on debugging to trace the matching process:

      a = Qt::Application.new(ARGV)
      Qt.debug_level = Qt::DebugLevel::High
      a.loadLibrary("foo")  # Non existent method

Will give the following output:

      classname    == QApplication
      :: method == loadLibrary$
      -> methodIds == []
      candidate list:
      Possible prototypes:
          static QWidget* QApplication::widgetAt(int, int, bool)
			...

Here, the list of candidate methods 'methodIds' is empty

Another debugging mechanism allows various trace 'channels' to be switched on.

You can trace virtual method callbacks:

      Qt::Internal::setDebug(Qt::QtDebugChannel::QTDB_VIRTUAL)

Or trace QtRuby garbage collection:

      Qt::Internal::setDebug(Qt::QtDebugChannel::QTDB_GC)

字符串国际化

QtRuby 支持'u'、'e' 和 's' 的 $KCODE 值或命令行的对应 '-K'选项。Qt Designer .ui 文件有 UTF-8 字符串，因此，如果您要使用任何8位的 UTF - 8 字符，您将需要设定 $KCODE='u' 或使用 -Ku命令行选项。

其他功能和产品

Qt Designer

「rbuic4」工具包含在qtruby/tools/rbuic，用于编译 .ui 檔加入到 Ruby 程序代码中。如上所述，Qt Designer 使用UTF-8。除了原始的 uic C++ 实用工具的选项还要加上 '-x' 标签。This will generate a top level stub in the code:

      $ rbuic mainform.ui -x -o mainform.rb

Will add this to the end of the generated code:

      if $0 == __FILE__
          a = Qt::Application.new(ARGV)
          w = MainForm.new
          w.show
          a.exec
      end

Then you can test the example code straight away:

      $ ruby mainform.rb

Use the '-kde' option to require the 'korundum4' extension rather than the 'Qt4' one. If the '-x' option is used in conjunction, it generates a KDE top level. For example:

      $ rbuic4 -x -kde knotifywidgetbase.ui -o knotifywidgetbase.rb

Will generate this top level code:

      if $0 == __FILE__
      	about = KDE::AboutData.new("knotifywidgetbase", 
		                           "KNotifyWidgetBase", "0.1")
      	KDE::CmdLineArgs.init(ARGV, about)
        a = KDE::Application.new()
    	w = KNotifyWidgetBase.new
    	w.show
    	a.exec
      end

Qt::UILoader运行时加载.ui文件

You can load a Qt Designer .ui file at runtime with the 'quiloader' extension, for example:

      require 'Qt4'
      require 'quiloader'

      a = Qt::Application.new(ARGV)
      if ARGV.length == 0
        exit
      end

      if ARGV.length == 2
        QUI::WidgetFactory.loadImages ARGV[0]
        w = QUI::WidgetFactory.create ARGV[1]
        if w.nil?
          exit
        end
        w.show()
        a.connect(a, SIGNAL('lastWindowClosed()'), a, SLOT('quit()'))
        a.exec()
      end

API参考

使用 bin/rbqtapi 工具，以了解 QtRuby api 提供哪些方法。指令：

	  $ rbqtapi Qt::TextEdit

将列出 Qt::TextEdit 类别中所有的方法

	  $ rbqtapi -rsetCaption 

列出所有名称包含字符串'setCaption'的方法

例子

入门 QtRuby 程序设计的最佳方式是看一些现有的程序代码，并开始弄乱它。在 qtrubyexamples 和 korundum/examples 中有各式各样例子。

KDE相关信息

KDE 程序不是用 require 'Qt4'，而是用 require 'korundum4'

The KDE K* classes such as KApplication are renamed as KDE::Application. The other KDE classes are in the KParts::, KIO:: or DOM:: namespaces, with the same names as their C++ counterparts.

Use the 'rbkdeapi' script to introspect the Korundum api from the command line. For example:

      $ rbkdeapi KDE::Action

Will list all the methods in the KDE::Action class. There are currently (as at KDE 3.3 beta 2) 977 classes/30841 methods in the Smoke library runtime, so the coverage of the Qt/KDE api is pretty complete.

构建依赖

• ruby 1.8 或更高版本 (svn trunk works with 1.9.1)
• cmake 2.6 或更高版本
• Qt 4.0 或更高版本
• KDE 4.1 或更高版本（korundum 需要）

教程

There is a ruby translation of Qt Tutorial #1, and the corresponding ruby code is in qtruby/rubylib/tutorial/t1 to t14.

相同的教学的Qt4版本，由 Darshan Ishaya 翻译为 Ruby，Qt4 教学 #1

Qt Tutorial #2, a Charting Application with ruby code in qtruby/rubylib/examples/qt-examples/chart.

The Qt Designer Color Tool Tutorial, with ruby code in qtruby/rubylib/designer/examples/colortool.

Paul Lutus has written a tutorial on how to get started with Ruby GUI programming with Qt

For KDE, there is a ruby translation of this KDE 3.0 tutorial originally written for C++ by Antonio Larrosa Jiménez. The sources are in korundum/rubylib/tutorials/p1 to p9.

The book Rapid GUI Development with QtRuby is now available.

下载

您可以从 RubyForge 的QtRuby/Korundum 网站取得最新的 SVN 快照。

更多帮助

在FreeNode有两个 IRC 频道（#qtruby and #kde-ruby）。如果你偏好电子邮件，您可以使用 kde-bindings 邮件列表（低流量），或者在 ruby-talk 邮件列表提问（您可以使用 Ruby 论坛 gateway，从网页发表文章到 ruby-talk）。

更多信息

ruby Qt 的系列文章（灵感来自dradis项目的工作）：

• ruby workshop: the way of the Qt samurai
• ruby Qt: model / view / controller
• ruby Qt：选单列、状态栏和资源
• ruby Qt 自定 widget 范例
• ruby Qt::TreeWidget 范例
• Very usefull link how to create your first Qt window dialog