Qt ruby 添加按钮

编程
1 
require 'Qt'
Qt::Application.new(ARGV)do
    Qt::Widget.new do
        self.window_title='hi!'
        label=Qt::Label.new('hello')
        self.resize 400,200
        button=Qt::PushButton.new('hello SuSE!') do
            connect(SIGNAL :clicked) {
                    label.show
            }
        end
        bye = Qt::PushButton.new('okey, bye') {
            connect (SIGNAL :clicked) do
                label.hide
            end
        }
        quit = Qt::PushButton.new('quit') do
            connect(SIGNAL :clicked){Qt::Application.instance.quit}
        end
        self.layout=Qt::VBoxLayout.new do
            add_widget(button,0,Qt::AlignCenter)
            add_widget(bye,0,Qt::AlignRight)
            add_widget(quit,0,Qt::AlignRight)
        end
        show
    end
    exec
end

先挖个坑，也请大家指出来哪里需要重点解释！