Languages/Ruby: Difference between revisions

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    {{Template:I18n/Language Navigation Bar|Development/Languages/Ruby}}
    {{Warning|Some important links are non-functional, specially the official Korundum page. Until we solve this problem you can find the source code at [https://projects.kde.org/projects/kde/kdebindings/ruby kdebindings project page]}}
     
     
    [[Image:ruby.png]]
    [[Image:ruby.png]]


    Line 12: Line 14:
    = QtRuby =
    = QtRuby =
    Hello world example:
    Hello world example:
    <code>
    <syntaxhighlight lang="ruby">
    #!/usr/bin/ruby -w
    #!/usr/bin/ruby -w
    require 'Qt4'
    require 'Qt4'
    Line 20: Line 22:
    hello.show
    hello.show
    a.exec
    a.exec
    </code>
    </syntaxhighlight>


    Hello Qt example in a more 'Rubyish' way:
    Hello Qt example in a more 'Rubyish' way:


    <code>
    <syntaxhighlight lang="ruby">
    require 'Qt4'
    require 'Qt4'


    Line 49: Line 51:
         exec
         exec
    end
    end
     
    </syntaxhighlight>
    </code>


    = Current api coverage overview =
    = Current api coverage overview =
    Line 65: Line 66:


    Any underscores in method names are removed, and the following character is capitalised. For example, you can use either of these two forms to call the same method:
    Any underscores in method names are removed, and the following character is capitalised. For example, you can use either of these two forms to call the same method:
          create_standard_status_bar_action()
     
          createStandardStatusBarAction()
    <syntaxhighlight lang="ruby">
    create_standard_status_bar_action()
    createStandardStatusBarAction()
    </syntaxhighlight>


    ==Operator overloading==
    ==Operator overloading==
    The full range of Qt operator methods is available, for example:
    The full range of Qt operator methods is available, for example:


          p1 = Qt::Point.new(5,5)  => (5, 5)
    <syntaxhighlight lang="ruby">
          p2 = Qt::Point.new(20,20) => (20, 20)
    p1 = Qt::Point.new(5,5)  => (5, 5)
          p1 + p2                  => (25, 25)
    p2 = Qt::Point.new(20,20) => (20, 20)
    p1 + p2                  => (25, 25)
    </syntaxhighlight>


    ==Declare signals and slots==
    ==Declare signals and slots==
    Signals and slots are declared as list of strings like this:
    Signals and slots are declared as list of strings like this:


          slots 'setColor(QColor)', 'slotLoad(const QString&)'..
    <syntaxhighlight lang="ruby">
          signals 'clicked()'..
    slots 'setColor(QColor)', 'slotLoad(const QString&)'..
    signals 'clicked()'..
    </syntaxhighlight>


    For slots and signals without arguments you can use Ruby symbols:
    For slots and signals without arguments you can use Ruby symbols:


           
    <syntaxhighlight lang="ruby">
    Currently C++ type signatures must be used, a future version of QtRuby will allow ruby type signatures instead.
    slots :slotLoad
    signals :clicked
    </syntaxhighlight>
     
    Currently C++ type signatures must be used, a future version of QtRuby will allow ruby type signatures instead. (see the section on emitting Ruby Classes)


    Connect slots and signals like this:
    Connect slots and signals like this:


          Qt::Object.connect( @colormenu, SIGNAL( "activated( int )" ),
    <syntaxhighlight lang="ruby">
                            self, SLOT( "slotColorMenu( int )" ) )
    Qt::Object.connect( @colormenu, SIGNAL( "activated(int)" ),
                      self, SLOT( "slotColorMenu(int)" ) )
    </syntaxhighlight>
     
    There is also two another possibilities:
     
    <syntaxhighlight lang="ruby">
    connect(:mysig, mytarget, :mymethod))
    connect(SIGNAL('mysignal(int)'), mytarget, :mymethod))
    </syntaxhighlight>


    Or you can connect signal to a block:
    Or you can connect signal to a block:


          quit_button.connect(SIGNAL :clicked) { $qApp.quit }
    <syntaxhighlight lang="ruby">
    quit_button.connect(SIGNAL :clicked) { $qApp.quit }
    </syntaxhighlight>


    And emit signals like this:
    And emit signals like this:


          emit colorChanged( black )
    <syntaxhighlight lang="ruby">
    emit colorChanged( black )
    </syntaxhighlight>
     
    ==Emitting Ruby Classes==
    Ruby classes can be emitted by embedding them inside a QVariant, and emitting the QVariant.
     
    The following code provides a method called to_variant that can be used to easily convert objects to Variants
    <syntaxhighlight lang="ruby">
    class Qt::RubyVariant < Qt::Variant
        def initialize(value)
            super()
            @value = value
        end
     
        attr_accessor :value
    end
     
    class Object
        def to_variant
            Qt::RubyVariant.new self
        end
    end
    </syntaxhighlight>
     
    Note: as of KDE 4.5 you can simply use
    <syntaxhighlight lang="ruby">
    variant = Qt::Variant.fromValue(my_ruby_object)
    </syntaxhighlight>
    to create a QVariant that contains your ruby object. To get it back, you just call Qt::Variant#value as usual.
     
    This can be used as follows
    <syntaxhighlight lang="ruby">
    class MyObject < Qt::Object
        signals "mySignal(QVariant)"
        def doEmit
            # since KDE 4.5:
            # emit mySignal(Qt::Variant.fromValue(ruby_object))
            emit mySignal(ruby_object.to_variant)
        end
     
        slots "mySlot(QVariant)"
        def mySlot(variant)
            ruby_object = variant.value
        end
    end
    </syntaxhighlight>
     
    === Alternate way to emit Ruby Classes ===
    You can also try to emit a ruby class by emitting it's object_id (either as an Integer or a QVariant), and use ObjectSpace._id2ref to get the object back.
     
    <syntaxhighlight lang="ruby">
    class Object
        def to_variant
            Qt::Variant.new object_id
        end
    end
     
    class Qt::Variant
        def to_object
            ObjectSpace._id2ref to_int
        end
    end
    </syntaxhighlight>


    ==Constructors==
    ==Constructors==
    You can call constructors in the conventional style:
    You can call constructors in the conventional style:


          quit = Qt::PushButton.new("Quit", self, "quit")
    <syntaxhighlight lang="ruby">
    quit = Qt::PushButton.new("Quit", self, "quit")
    </syntaxhighlight>


    Or you can pass a block if you prefer:
    Or you can pass a block if you prefer:


          w = MyWidget.new { setCaption("foobar") }
    <syntaxhighlight lang="ruby">
    w = MyWidget.new { setCaption("foobar") }
    </syntaxhighlight>


    The block will be called in the context of the newly created instance.
    The block will be called in the context of the newly created instance.
    Line 115: Line 202:
    Ordinary arguments can be provided as well as a block at the end:
    Ordinary arguments can be provided as well as a block at the end:


          w = MyWidget.new(nil) { setCaption("foobar") }
    <syntaxhighlight lang="ruby">
    w = MyWidget.new(nil) { setCaption("foobar") }
    </syntaxhighlight>


    They are run in the context of the new instance.
    They are run in the context of the new instance.
    Line 121: Line 210:
    And there's more! You can also pass an arg to the block, and it will be run in the context of the arg:
    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" }
    <syntaxhighlight lang="ruby">
    w = MyWidget.new { |theWidget| theWidget.setCaption "foobar" }
    </syntaxhighlight>


    ==Garbage Collection==
    ==Garbage Collection==
    When a ruby instance is garbage collected, the underlying C++ instance will only be deleted if it isn't 'owned' by a parent object. Normally this will 'just work', but there are occasions when you need to delete the C++ ahead of garbage collection, and whether or not it has a parent. Use the dispose(), isDisposed() and disposed? methods like this:
    When a ruby instance is garbage collected, the underlying C++ instance will only be deleted if it isn't 'owned' by a parent object. Normally this will 'just work', but there are occasions when you need to delete the C++ ahead of garbage collection, and whether or not it has a parent. Use the dispose(), isDisposed() and disposed? methods like this:


          item2.dispose
    <syntaxhighlight lang="ruby">
          if item2.disposed?
    item2.dispose
          puts "item2 is disposed"
    if item2.disposed?
          end
    puts "item2 is disposed"
    end
    </syntaxhighlight>


    ==C++ 'int*' and 'int&' argument types==
    ==C++ 'int*' and 'int&' argument types==
    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()':
    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,  
    <syntaxhighlight lang="ruby">
          #                              int *accuracy=0 );
    # static Ptr findByFileContent( const QString &fileName,  
    #                              int *accuracy=0 );
          acc = Qt::Integer.new(0)
          fc = KDE::MimeType.findByFileContent("mimetype.rb", acc)
       
       
    acc = Qt::Integer.new(0)
    fc = KDE::MimeType.findByFileContent("mimetype.rb", acc)
    </syntaxhighlight>


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


    ==C++ 'bool*' and 'bool&' argument types==
    ==C++ 'bool*' and 'bool&' argument types==
    There is a similar problem for bool arg types, and the mutable Qt::Boolean class can be used like this:
    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,  
    <syntaxhighlight lang="ruby">
          #              QWidget* parent = 0, const char *name = 0);
    # QFont getFont(bool * ok, const QFont&initial,  
    #              QWidget* parent = 0, const char *name = 0);
     
     
          ok = Qt::Boolean.new
    ok = Qt::Boolean.new
          font = Qt::FontDialog.getFont(ok,  
    font = Qt::FontDialog.getFont(ok,  
                              Qt::Font.new("Helvetica [Cronyx]", 10),  
                        Qt::Font.new("Helvetica [Cronyx]", 10),  
                              self)
                        self)
          if !ok.nil?  
    if !ok.nil?  
          # font is set to the font the user selected
    # font is set to the font the user selected
          else  
    else  
          # the user canceled the dialog
    # the user canceled the dialog
          end
    end
    </syntaxhighlight>


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


    ==C++ (const )(unsigned )char* argument types==
    ==C++ (const )(unsigned )char* argument types==
     
    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!
    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 it's 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==
    ==C++ unsigned char* functions==
    Line 173: Line 265:


    ==Debugging==
    ==Debugging==
    If a method call can't be matched in the Smoke library giving a 'method_missing' error, first check that you are passing correct class instance that is properly initialized (with super method called in constructors of custom Qt classes descendants). You can also turn on debugging to trace the matching process:


    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:
    <syntaxhighlight lang="ruby">
     
    a = Qt::Application.new(ARGV)
          a = Qt::Application.new(ARGV)
    Qt.debug_level = Qt::DebugLevel::High
          Qt.debug_level = Qt::DebugLevel::High
    a.loadLibrary("foo")  # Non existent method
          a.loadLibrary("foo")  # Non existent method
    </syntaxhighlight>


    Will give the following output:
    Will give the following output:
    Line 189: Line 282:
               static QWidget* QApplication::widgetAt(int, int, bool)
               static QWidget* QApplication::widgetAt(int, int, bool)
      ...
      ...
    Here, the list of candidate methods 'methodIds' is empty
    Here, the list of candidate methods 'methodIds' is empty


    Line 195: Line 289:
    You can trace virtual method callbacks:
    You can trace virtual method callbacks:


          Qt::Internal::setDebug(Qt::QtDebugChannel::QTDB_VIRTUAL)
    <syntaxhighlight lang="ruby">
    Qt::Internal::setDebug(Qt::QtDebugChannel::QTDB_VIRTUAL)
    </syntaxhighlight>


    Or trace QtRuby garbage collection:
    Or trace QtRuby garbage collection:


          Qt::Internal::setDebug(Qt::QtDebugChannel::QTDB_GC)
    <syntaxhighlight lang="ruby">
    Qt::Internal::setDebug(Qt::QtDebugChannel::QTDB_GC)
    </syntaxhighlight>


    ==String i18n==
    ==String i18n==
    Line 208: Line 306:


    ==Qt Designer==
    ==Qt Designer==
    A 'rbuic4' tool is included in qtruby/tools/rbuic to compile .ui files into ruby code. As described above, Qt Designer uses UTF-8. In addition to the options in the original uic C++ utility an '-x' flag has been added. This will generate a top level stub in the code:


    A 'rbuic' tool is included in qtruby/rubylib/designer/rbuic to compile .ui files into ruby code. As described above, Qt Designer uses UTF-8. In addition to the options in the original uic C++ utility an '-x' flag has been added. This will generate a top level stub in the code:
    <syntaxhighlight lang="bash">
     
    $ rbuic mainform.ui -x -o mainform.rb
          $ rbuic mainform.ui -x -o mainform.rb
    </syntaxhighlight>


    Will add this to the end of the generated code:
    Will add this to the end of the generated code:


          if $0 == __FILE__
    <syntaxhighlight lang="ruby">
              a = Qt::Application.new(ARGV)
    if $0 == __FILE__
              w = MainForm.new
        a = Qt::Application.new(ARGV)
              a.setMainWidget(w)
        w = MainForm.new
              w.show
        w.show
              a.exec
        a.exec
          end
    end
    </syntaxhighlight>


    Then you can test the example code straight away:
    Then you can test the example code straight away:
    Line 227: Line 327:
           $ ruby mainform.rb
           $ ruby mainform.rb


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


          $ rbuic -x -kde knotifywidgetbase.ui -o knotifywidgetbase.rb
    <syntaxhighlight lang="bash">
    $ rbuic4 -x -kde knotifywidgetbase.ui -o knotifywidgetbase.rb
    </syntaxhighlight>


    Will generate this top level code:
    Will generate this top level code:


          if $0 == __FILE__
    <syntaxhighlight lang="ruby">
          about = KDE::AboutData.new("knotifywidgetbase",  
    if $0 == __FILE__
                              "KNotifyWidgetBase", "0.1")
        about = KDE::AboutData.new("knotifywidgetbase",  
          KDE::CmdLineArgs.init(ARGV, about)
                          "KNotifyWidgetBase", "0.1")
            a = KDE::Application.new()
        KDE::CmdLineArgs.init(ARGV, about)
        w = KNotifyWidgetBase.new
        a = KDE::Application.new()
        a.setMainWidget(w)
        w = KNotifyWidgetBase.new
        w.show
        w.show
        a.exec
        a.exec
          end
    end
    </syntaxhighlight>
     
    ==Loading .ui files at runtime with Qt::UiLoader==
     
    Let's say you created a file in your project directory called 'gui.ui' using Qt Designer ('/usr/bin/designer', comes with Qt. At least on Arch).
    You can load it like so:
     
    <syntaxhighlight lang="ruby">
    require 'Qt4'
    require 'qtuitools'


    ==Loading .ui files at runtime with QUI::WidgetFactory==
    class MyApp < Qt::Application
        def initialize
            super ARGV


    You can load a Qt Designer .ui file at runtime with the 'qui' extension, for example:
            # 'gui.ui' was created with qt designer ('designer' on arch linux)
            file = Qt::File.new 'gui.ui' do
                open Qt::File::ReadOnly
            end
           
            window = Qt::UiLoader.new.load file


          require 'Qt'
            file.close
          require 'qui'
          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


    ==QtRuby shell==
            if window.nil?
                print "Error. Window is nil.\n"
                exit
            end
            window.show
        end
    end


    You can use the QtRuby shell in bin/rbqtsh to create widgets interactively from the command line.
    a = MyApp.new
    a.exec
    </syntaxhighlight>


    ==API reference==
    ==API reference==


    Use the bin/rbqtapish tool to discover which methods are available in the QtRuby api. This command:
    Use the bin/rbqtapi tool to discover which methods are available in the QtRuby api. This command:


      $ rbqtapish Qt::TextEdit
    <syntaxhighlight lang="bash">
    $ rbqtapi Qt::TextEdit
    </syntaxhighlight>


    Will list all the methods in the Qt::TextEdit class
    Will list all the methods in the Qt::TextEdit class


      $ rbqtapi -rsetCaption  
    <syntaxhighlight lang="bash">
    $ rbqtapi -rsetCaption  
    </syntaxhighlight>


    Lists all methods whose names contain the string 'setCaption'
    Lists all methods whose names contain the string 'setCaption'
    Line 285: Line 399:
    ==Example programs==
    ==Example programs==


    The best way to start programming QtRuby is to look at some existing code and start messing with it.. The are various samples under qtruby/rubylib/examples and korundum/rubylib/examples.
    The best way to start programming QtRuby is to look at some existing code and start messing with it.. The are various samples under qtrubyexamples and korundum/examples.


    =KDE Specific Infomation=
    ==Writing Unit Tests==
    Using Ruby allows you the power to leverage testing frameworks such as RSpec in order to unit and integration test your classes.


    Instead of <code>require 'Qt'</code>, use <code>require 'Korundum'</code> for KDE programs.
    Most classes such as Models can be easily tested via the APIs they expose. Below is a small extract with some interesting tests from the mingle_mover project (http://github.com/gja/mingle_mover). The class being tested is a TableModel


    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.
    Note how we create a stub to pass to QAbstractTableModel::data, which accepts a QModelIndex as an argument.


    Use the 'rbkdeapi' script to introspect the Korundum api from the command line. For example:
    <syntaxhighlight lang="ruby">
    describe CardModel do
        it "Should Implement QAbstractTableModel" do
            CardModel.ancestors.should include Qt::AbstractTableModel
        end


          $ rbkdeapi KDE::Action
        it "Should Not Be Editable" do
            @model.data(mock_index(1,2), Qt::EditRole).should_not be_valid
            @model.headerData(nil, nil, Qt::EditRole).should_not be_valid
           
            flags = @model.flags(nil)
            flags.should have_flag Qt::ItemIsEnabled
            flags.should have_flag Qt::ItemIsSelectable
            flags.should_not have_flag Qt::ItemIsEditable
        end


    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.
        it "Should not return any vertical headers" do
            @model.headerData(1, Qt::Vertical).should_not be_valid
        end


    =DCOP Support=
        it "Should color a row according to the status" do
            @model.data(mock_index(1,2), Qt::ForegroundRole).value.color.should == Qt::Color.new(Qt::red)
            @model.data(mock_index(0,2), Qt::ForegroundRole).value.color.should == Qt::Color.new(Qt::green)
            @model.data(mock_index(0,0), Qt::ForegroundRole).should_not be_valid
        end


    Here is a minimal ruby dcop slot implementation:
        def mock_index(row, col)
            stub(:row => row, :column => col)
        end


          require 'Korundum'
        def have_flag(flag)
            return simple_matcher("A flag that matches " + flag.to_s) { |given| (given & flag) != 0 }
          class MyWidget < KDE::PushButton
        end
            k_dcop 'QPoint mySlot(int,QString)'
    end
    </syntaxhighlight>
            def initialize(parent, name)
                  super
              end
            def mySlot(counter,greeting)
                  return Qt::Point.new(50, 100)
            end
          end  


    This slot is passed an integer and a string, and returns a Qt::Point.
    === Testing Out Signals and Slots ===
    Below is a simple class which can be used to test out a class via the signals it emits:


    Note that the class doesn't have to inherit from DCOPObject. If you include a 'k_dcop' slots declaration a 'listener' dcop object instance is created automatically, and these four methods are added to your class:
    <syntaxhighlight lang="ruby">
    class RubySignalSpy < Qt::Object
        def self.create(*args, &block)
            Class.new(self).new(*args, &block)
        end


          interfaces()
        def count(name)
          functions()
            @calls[name].size
          connectDCOPSignal()
        end
          disconnectDCOPSignal()


    The name of the object is always the ruby classname, and you can only instantiate one instance for each ruby class that has 'k_dcop' declarations. See examples/dcop/dcopslot.rb and dcopsignal.rb for an example of the simplest approach.
        def params(name, invocation = 0)
            @calls[name][invocation]
        end


    If you wish to use the full functionality of a DCOPObject, you can subclass it and call all the methods, not just the four above. Additionally, you can instantiate more than one instance per class and rename the dcop object with the setObjId() method or by passing the name to the constructor. See the examples/dcop/petshop.rb code for an example of a more complex dcop object.
        def method_missing(name, *args, &block)
            @calls[name.to_sym] << args
            exec_action_for(name, args)
        end


    Define a dcop slot like this in one ruby program:
        def responds_to?(name)
            true
        end


          k_dcop 'QPoint getPoint(QString)'
      private
        def initialize
          def getPoint(msg)
            @calls = {}
              puts "message: #{msg}"
            def @calls.[](index)
              return Qt::Point.new(50, 100)
                super || self[index] = []
          end
            end
            @actions = {}
            super
        end


    Call it from another program and print the reply, like this:
        def mocked_slots(*names, &block)
            slots *names
            names.each { |name| @actions[name] = block }
        end


          dcopRef = KDE::DCOPRef.new("dcopslot", "MyWidget")
        def exec_action_for(name, args)
            @actions[name].call(self, args) if @actions[name]
        end


    There are three different ways to specify a DCOP call:
        def slots(*args)
            self.class.slots(*args)
        end
    end
    </syntaxhighlight>


          res = dcopRef.call("getPoint(QString)", "Hello from dcopcall")
    <syntaxhighlight lang="ruby">
          res = dcopRef.call("getPoint", "Hello from dcopcall")
          it "Should be able to emit a signal when called" do
          res = dcopRef.getPoint("Hello from dcopcall")
            reciever = RubySignalSpy.create do
                slots "recieved(int, int)"                     # Explicitly name slots with parameters
                mocked_slot :some_other_slot do |spy, params|  # Pass a block to be executed when called
                end                                            # You must call mocked_slot with a symbol
            end


    If the dcop slot has a 'void' or 'ASYNC' type, the result will be true if the call succeeds or nil if it fails
            class ClassWeAreTesting < Qt::Object
                signals "sending(int, int)"
                def broadcast
                    emit sending(4, 2)
                end
            end


    ==DCOP Attributes==
            sender = ClassWeAreTesting.new


    You can set a dcop attribute like this, instead of calling:
            Qt::Object.connect(sender, SIGNAL("sending(int, int)"), reciever, SLOT("recieved(int, int)"))
            sender.broadcast
            reciever.count(:recieved).should == 1              # Get count of calls
            reciever.params(:recieved, 0).should == [4, 2]      # Get the parameters of nth invocation
        end
    </syntaxhighlight>


          klipper.setClipboardContents("Hello there klipper")
    === Testing UI Classes ===
    It is much more difficult to test UI classes. In most cases, you will need to instantiate a QApplication so that you can create your widgets.  


    Assign to the DCOP attribute:
    Some rudimentary tests can be written by simulating clicks are various locations. Watch this space as more tests get written
    <syntaxhighlight lang="ruby">
    describe SomeTableView do
        before(:all) do
            @app = Qt::Application.new(ARGV)
            @view = SomeTableView.new
        end


           klipper = DCOPRef.new("klipper", "klipper")
        it "Should accept a mouse click on second row"        
          klipper.clipboardContents = "Hello there klipper"
            @row2 = @view.rowViewportPosition 1
            @view.mousePressEvent(Qt::MouseEvent.new(Qt::Event::MouseButtonPress, Qt::Point.new(0,@row2), Qt::LeftButton, Qt::LeftButton, Qt::NoModifier))
            # Assert something here, such as that a signal has been emitted
        end


    Amaze your friends! Do the programming equivalent of leaping over tall buildings in one bound! Here with one line of quite clear code, we read a file from disc and assign it the 'clipboardContents' klipper attribute via dcop:
        after(:all) do
            @app.dispose!
        end
    end
    </syntaxhighlight>


          klipper.clipboardContents = IO.readlines("myfile").to_s
    =KDE Specific Infomation=
    Instead of <syntaxhighlight lang="ruby">require 'Qt4'</syntaxhighlight>, use<syntaxhighlight lang="ruby">require 'korundum4'</syntaxhighlight> for KDE programs.


    ==DCOP Predicates==
    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.


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


          result = dcopRef.isFoo()
    <syntaxhighlight lang="bash">
    $ rbkdeapi KDE::Action
    </syntaxhighlight>


    You can use this more rubyish form:
    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.
     
          if dcopRef.foo?
              puts "foo is true"
          else
              puts "foo? is false"
          end
     
    Similarly you can use foo? as an alias for methods of the form hasFoo(). See examples/dcop/dcoppredicate.rb and dcopslot.rb
     
    ==Underscore to CamelCase DCOP method name conversion==
     
    Any underscores in a method name are removed, and the following character is capitalised. For example:
     
          res = dcopRef.get_point("Hello from dcopsend")
     
    Is a synonym for:
     
          res = dcopRef.getPoint("Hello from dcopsend")
     
    ==Send to a DCOPRef==
     
    There are two different ways to specify a DCOP send:
     
          res = dcopRef.send("mySlot(QString)", "Hello from dcopsend")
          res = dcopRef.send("mySlot", "Hello from dcopsend")
     
    The result will either be true or false (but not nil for fail like DCOPRef.call() method described above).
     
    When a call of the form 'dcopRef.getPoint(5, "foobar")' is made, the C++ type signature is obtained from the list of those returned by DCOPRef.functions(). However, if a method name is overloaded the ruby argument types are used to derive a type signature, in order to resolve the call like this:
     
          String => QString
          Float => double
          Integer => int
          TrueClass|FalseClass (ie 'true' or 'false') => bool
          Qt::Widget etc => QWidget
          KDE::URL etc => KURL
          Array => QStringList
     
    Specify the full C++ type signature using the form 'dcopRef.call("getPoint(int,QString)", 5, "foobar")' if these rules fail to pick the right method.
     
    ==Defining DCOP Signals==
     
          k_dcop_signals 'void testEmitSignal(QString)'
          def doit()
              emit testEmitSignal("Hello DCOP Slot")
          end
     
    Connect slot 'mySlot' to a DCOP signal like this:
     
          res = slottest.connectDCOPSignal("dcopsignal",
                                  "SenderWidget",
                                  "testEmitSignal(QString)",
                                  "mySlot(QString)",
                                  true)


    =Build dependencies=
    =Build dependencies=


    * ruby 1.8 or greater
    * ruby 1.8 or greater (svn trunk works with 1.9.1)
    * automake 1.7 or greater
    * cmake 2.6 or greater
    * Qt 3.1 or greater
    * Qt 4.0 or greater
    * KDE 3.1 or greater (for korundum)
    * KDE 4.1 or greater (for korundum)


    =Tutorials=
    =Tutorials=
    There is a ruby translation of [http://developer.kde.org/language-bindings/ruby/tutorial/tutorial.html Qt Tutorial #1], and the corresponding ruby code is in qtruby/rubylib/tutorial/t1 to t14.
    There is a ruby translation of [http://developer.kde.org/language-bindings/ruby/tutorial/tutorial.html Qt Tutorial #1], and the corresponding ruby code is in qtruby/rubylib/tutorial/t1 to t14.


    And a Qt4 version of the same tutorial translated to Ruby by Darshan Ishaya [http://www.darshancomputing.com/qt4-qtruby-tutorial/ Qt4 Tutorial #1]  
    And a Qt4 version of the same tutorial translated to Ruby by Darshan Ishaya [[Development/Tutorials/Qt4_Ruby_Tutorial|Qt4 Ruby Tutorial]]  


    [http://developer.kde.org/language-bindings/ruby/tutorial2/tutorial2.html Qt Tutorial #2], a Charting Application with ruby code in qtruby/rubylib/examples/qt-examples/chart.
    [http://developer.kde.org/language-bindings/ruby/tutorial2/tutorial2.html Qt Tutorial #2], a Charting Application with ruby code in qtruby/rubylib/examples/qt-examples/chart.
    Line 451: Line 576:


    The book [http://www.pragmaticprogrammer.com/titles/ctrubyqt/ Rapid GUI Development with QtRuby] is now available.
    The book [http://www.pragmaticprogrammer.com/titles/ctrubyqt/ Rapid GUI Development with QtRuby] is now available.
    There is also an approach to create an [[/Ruby-Qt/KDE Book|Ruby-Qt/KDE Book]] under a free license. The content will be created in this wiki. The book made with latex will be derived from the content in the wiki. Any Questions? Contact [[User:SaLOUt|me]]!


    =Download=
    =Download=
    Line 465: Line 592:
    * [http://weblog.nomejortu.com/x-windows/ruby-qt-custom-widget-example ruby Qt custom widget example]
    * [http://weblog.nomejortu.com/x-windows/ruby-qt-custom-widget-example ruby Qt custom widget example]
    * [http://weblog.nomejortu.com/x-windows/ruby-qttreewidget-example ruby Qt::TreeWidget example]
    * [http://weblog.nomejortu.com/x-windows/ruby-qttreewidget-example ruby Qt::TreeWidget example]
    * [http://www.ruby-forum.com/topic/189346#new Very useful link how to create your first Qt window dialog]


    [[Category:Ruby]]
    [[Category:Ruby]]

    Revision as of 17:39, 10 March 2016

    Warning
    Some important links are non-functional, specially the official Korundum page. Until we solve this problem you can find the source code at kdebindings project page


    Very complete bindings to both the KDE API and the Qt APIs. The Korundum package includes both a QtRuby Qt-only binding along with the full combined Qt/KDE one. The QtRuby package contains just Qt bindings with no dependencies on KDE.

    Korundum/QtRuby - Ruby-KDE/Qt bindings

    The book Rapid GUI Development with QtRuby (for Qt version 3.x) is available.

    Being Smoke-based bindings means that they offer full access to most KDE 4.x and Qt 4.x classes.

    QtRuby

    Hello world example:

    #!/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 example in a more 'Rubyish' way:

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

    Current api coverage overview

    Available calls

    You can call all Qt public and protected methods, and all friend methods such as bitBlt() etc

    Virtual methods

    All virtual methods can be overridden, not just event handlers

    Properties

    'foobar = 5' is a synonym for 'setFooBar(5)'

    Use either CamelCase or lowercase with underscore naming

    Any underscores in method names are removed, and the following character is capitalised. For example, you can use either of these two forms to call the same method:

    create_standard_status_bar_action()
    createStandardStatusBarAction()
    

    Operator overloading

    The full range of Qt operator methods is available, for example:

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

    Declare signals and slots

    Signals and slots are declared as list of strings like this:

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

    For slots and signals without arguments you can use Ruby symbols:

    slots :slotLoad
    signals :clicked
    

    Currently C++ type signatures must be used, a future version of QtRuby will allow ruby type signatures instead. (see the section on emitting Ruby Classes)

    Connect slots and signals like this:

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

    There is also two another possibilities:

    connect(:mysig, mytarget, :mymethod))
    connect(SIGNAL('mysignal(int)'), mytarget, :mymethod))
    

    Or you can connect signal to a block:

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

    And emit signals like this:

    emit colorChanged( black )
    

    Emitting Ruby Classes

    Ruby classes can be emitted by embedding them inside a QVariant, and emitting the QVariant.

    The following code provides a method called to_variant that can be used to easily convert objects to Variants

    class Qt::RubyVariant < Qt::Variant
        def initialize(value)
            super()
            @value = value
        end
    
        attr_accessor :value
    end
    
    class Object
        def to_variant
            Qt::RubyVariant.new self
        end
    end
    

    Note: as of KDE 4.5 you can simply use

    variant = Qt::Variant.fromValue(my_ruby_object)
    

    to create a QVariant that contains your ruby object. To get it back, you just call Qt::Variant#value as usual.

    This can be used as follows

    class MyObject < Qt::Object
        signals "mySignal(QVariant)"
        def doEmit
            # since KDE 4.5:
            # emit mySignal(Qt::Variant.fromValue(ruby_object))
            emit mySignal(ruby_object.to_variant)
        end
    
        slots "mySlot(QVariant)"
        def mySlot(variant)
            ruby_object = variant.value
        end
    end
    

    Alternate way to emit Ruby Classes

    You can also try to emit a ruby class by emitting it's object_id (either as an Integer or a QVariant), and use ObjectSpace._id2ref to get the object back.

    class Object
        def to_variant
            Qt::Variant.new object_id
        end
    end
    
    class Qt::Variant
        def to_object
            ObjectSpace._id2ref to_int
        end
    end
    

    Constructors

    You can call constructors in the conventional style:

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

    Or you can pass a block if you prefer:

    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" }
    

    Garbage Collection

    When a ruby instance is garbage collected, the underlying C++ instance will only be deleted if it isn't 'owned' by a parent object. Normally this will 'just work', but there are occasions when you need to delete the C++ ahead of garbage collection, and whether or not it has a parent. Use the dispose(), isDisposed() and disposed? methods like this:

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

    C++ 'int*' and 'int&' argument types

    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*' and 'bool&' argument types

    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* argument types

    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.

    Debugging

    If a method call can't be matched in the Smoke library giving a 'method_missing' error, first check that you are passing correct class instance that is properly initialized (with super method called in constructors of custom Qt classes descendants). You can also 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)
    

    String i18n

    QtRuby supports $KCODE values of 'u', 'e' and 's' or the corresponding '-K' options from the command line. Qt Designer .ui files have UTF-8 strings so if you use any 8 bit UTF-8 characters, you will need to set $KCODE='u' or use the -Ku command line option.

    Other capabilities and offerings

    Qt Designer

    A 'rbuic4' tool is included in qtruby/tools/rbuic to compile .ui files into ruby code. As described above, Qt Designer uses UTF-8. In addition to the options in the original uic C++ utility an '-x' flag has been added. 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
    

    Loading .ui files at runtime with Qt::UiLoader

    Let's say you created a file in your project directory called 'gui.ui' using Qt Designer ('/usr/bin/designer', comes with Qt. At least on Arch). You can load it like so:

    require 'Qt4'
    require 'qtuitools'
    
    class MyApp < Qt::Application
        def initialize
            super ARGV
    
            # 'gui.ui' was created with qt designer ('designer' on arch linux)
            file = Qt::File.new 'gui.ui' do
                open Qt::File::ReadOnly
            end
            
            window = Qt::UiLoader.new.load file
    
            file.close
    
            if window.nil?
                print "Error. Window is nil.\n"
                exit
            end 
            window.show
        end
    end
    
    a = MyApp.new
    a.exec
    

    API reference

    Use the bin/rbqtapi tool to discover which methods are available in the QtRuby api. This command:

    $ rbqtapi Qt::TextEdit
    

    Will list all the methods in the Qt::TextEdit class

    $ rbqtapi -rsetCaption
    

    Lists all methods whose names contain the string 'setCaption'

    Example programs

    The best way to start programming QtRuby is to look at some existing code and start messing with it.. The are various samples under qtrubyexamples and korundum/examples.

    Writing Unit Tests

    Using Ruby allows you the power to leverage testing frameworks such as RSpec in order to unit and integration test your classes.

    Most classes such as Models can be easily tested via the APIs they expose. Below is a small extract with some interesting tests from the mingle_mover project (http://github.com/gja/mingle_mover). The class being tested is a TableModel

    Note how we create a stub to pass to QAbstractTableModel::data, which accepts a QModelIndex as an argument.

    describe CardModel do
        it "Should Implement QAbstractTableModel" do
            CardModel.ancestors.should include Qt::AbstractTableModel
        end
    
        it "Should Not Be Editable" do
            @model.data(mock_index(1,2), Qt::EditRole).should_not be_valid
            @model.headerData(nil, nil, Qt::EditRole).should_not be_valid
            
            flags = @model.flags(nil)
            flags.should have_flag Qt::ItemIsEnabled
            flags.should have_flag Qt::ItemIsSelectable
            flags.should_not have_flag Qt::ItemIsEditable
        end
    
        it "Should not return any vertical headers" do
            @model.headerData(1, Qt::Vertical).should_not be_valid
        end
    
        it "Should color a row according to the status" do
            @model.data(mock_index(1,2), Qt::ForegroundRole).value.color.should == Qt::Color.new(Qt::red)
            @model.data(mock_index(0,2), Qt::ForegroundRole).value.color.should == Qt::Color.new(Qt::green)
            @model.data(mock_index(0,0), Qt::ForegroundRole).should_not be_valid
        end
    
        def mock_index(row, col)
            stub(:row => row, :column => col)
        end
    
        def have_flag(flag)
            return simple_matcher("A flag that matches " + flag.to_s) { |given| (given & flag) != 0 }
        end
    end
    

    Testing Out Signals and Slots

    Below is a simple class which can be used to test out a class via the signals it emits:

    class RubySignalSpy < Qt::Object
        def self.create(*args, &block)
            Class.new(self).new(*args, &block)
        end
    
        def count(name)
            @calls[name].size
        end
    
        def params(name, invocation = 0)
            @calls[name][invocation]
        end
    
        def method_missing(name, *args, &block)
            @calls[name.to_sym] << args
            exec_action_for(name, args)
        end
    
        def responds_to?(name)
            true
        end
    
      private
        def initialize
            @calls = {}
            def @calls.[](index)
                super || self[index] = []
            end
            @actions = {}
            super
        end
    
        def mocked_slots(*names, &block)
            slots *names
            names.each { |name| @actions[name] = block }
        end
    
        def exec_action_for(name, args)
            @actions[name].call(self, args) if @actions[name]
        end
    
        def slots(*args)
            self.class.slots(*args)
        end
    end
    
          it "Should be able to emit a signal when called" do
            reciever = RubySignalSpy.create do
                slots "recieved(int, int)"                      # Explicitly name slots with parameters
                mocked_slot :some_other_slot do |spy, params|   # Pass a block to be executed when called
                end                                             # You must call mocked_slot with a symbol
            end
    
            class ClassWeAreTesting < Qt::Object
                signals "sending(int, int)"
                def broadcast
                    emit sending(4, 2)
                end
            end
    
            sender = ClassWeAreTesting.new
    
            Qt::Object.connect(sender, SIGNAL("sending(int, int)"), reciever, SLOT("recieved(int, int)"))
            sender.broadcast
            reciever.count(:recieved).should == 1               # Get count of calls
            reciever.params(:recieved, 0).should == [4, 2]      # Get the parameters of nth invocation
        end
    

    Testing UI Classes

    It is much more difficult to test UI classes. In most cases, you will need to instantiate a QApplication so that you can create your widgets.

    Some rudimentary tests can be written by simulating clicks are various locations. Watch this space as more tests get written

    describe SomeTableView do
        before(:all) do
            @app = Qt::Application.new(ARGV)
            @view = SomeTableView.new
        end
    
        it "Should accept a mouse click on second row"        
            @row2 = @view.rowViewportPosition 1
            @view.mousePressEvent(Qt::MouseEvent.new(Qt::Event::MouseButtonPress, Qt::Point.new(0,@row2), Qt::LeftButton, Qt::LeftButton, Qt::NoModifier))
            # Assert something here, such as that a signal has been emitted
        end
    
        after(:all) do
            @app.dispose!
        end
    end
    

    KDE Specific Infomation

    Instead of

    require 'Qt4'
    

    , use

    require 'korundum4'
    

    for KDE programs.

    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.

    Build dependencies

    • ruby 1.8 or greater (svn trunk works with 1.9.1)
    • cmake 2.6 or greater
    • Qt 4.0 or greater
    • KDE 4.1 or greater (for korundum)

    Tutorials

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

    And a Qt4 version of the same tutorial translated to Ruby by Darshan Ishaya Qt4 Ruby Tutorial

    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.

    There is also an approach to create an Ruby-Qt/KDE Book under a free license. The content will be created in this wiki. The book made with latex will be derived from the content in the wiki. Any Questions? Contact me!

    Download

    You can obtain recent SVN snapshots on the Rubyforge QtRuby/Korundum site.

    More help

    There are two IRC channels (#qtruby and #kde-ruby) in FreeNode. If you prefer e-mail, you can use the kde-bindings mailing-list (low traffic) or ask in the ruby-talk mailing list (you may use the Ruby Forum gateway to post in ruby-talk from web).

    More information

    A series of articles on ruby QT (inspired by the work done for the dradis project):