Question

Java Swing教程使用SwingUtilities.invokeLater创建GUI（如here）。为什么要解释这个here - 大多数Swing对象都不是线程安全的。另一方面，我见过的大多数JRuby Swing示例都只是在脚本中设置了顶部框架（如here - 存档中的'guis'目录）。

问题是，在JRuby脚本中创建应用程序顶部框架时，我应该遵循使用SwingUtilities.invokeLater（）的Java模式吗？

我有两个JRuby脚本，一个使用SwingUtilities.invokeLater（），另一个不使用：

java_import javax.swing.JFrame
java_import javax.swing.SwingUtilities
java_import java.awt.Dimension
java_import javax.swing.JButton
JavaThread = java.lang.Thread

class TopFrame < JFrame

  def initialize
    super
    init_components()

    pack()
    set_visible(true)

    puts '----------------------------------------'
    puts 'In JFrame constructor:'
    puts "Thread name: #{JavaThread.current_thread.name}"
    puts "Is event dispatch thread: #{SwingUtilities.event_dispatch_thread?}"
    JavaThread.current_thread.thread_group.list

  end

  def init_components()

    set_default_close_operation(JFrame::EXIT_ON_CLOSE)
    set_preferred_size(Dimension.new(400, 300))

    button = JButton.new('Button')
    button.add_action_listener do |event|
      puts '----------------------------------------'
      puts 'In action listener:'
      puts "Thread name: #{JavaThread.current_thread.name}"
      puts "Is event dispatch thread: #{SwingUtilities.event_dispatch_thread?}"
      JavaThread.current_thread.thread_group.list
    end

    get_content_pane.add(button)

  end

end

puts '----------------------------------------'
puts 'Before SwingUtilties.invokeLater():'
puts "Thread name: #{JavaThread.current_thread.name}"
puts "Is event dispatch thread: #{SwingUtilities.event_dispatch_thread?}"
JavaThread.current_thread.thread_group.list

SwingUtilities.invoke_later do
  TopFrame.new
end

puts '----------------------------------------'
puts 'After SwingUtilities.invokeLater():'
puts "Thread name: #{JavaThread.current_thread.name}"
puts "Is event dispatch thread: #{SwingUtilities.event_dispatch_thread?}"
JavaThread.current_thread.thread_group.list

输出结果为：

----------------------------------------
Before SwingUtilties.invokeLater():
Thread name: main
Is event dispatch thread: false
java.lang.ThreadGroup[name=main,maxpri=10]
    Thread[main,5,main]
    Thread[Ruby-0-JIT-1,1,main]
    java.lang.ThreadGroup[name=Ruby Threads#11483240,maxpri=10]
----------------------------------------
After SwingUtilities.invokeLater():
Thread name: main
Is event dispatch thread: false
java.lang.ThreadGroup[name=main,maxpri=10]
    Thread[main,5,main]
    Thread[Ruby-0-JIT-1,1,main]
    Thread[AWT-EventQueue-0,6,main]
    java.lang.ThreadGroup[name=Ruby Threads#11483240,maxpri=10]
----------------------------------------
In JFrame constructor:
Thread name: AWT-EventQueue-0
Is event dispatch thread: true
java.lang.ThreadGroup[name=main,maxpri=10]
    Thread[AWT-EventQueue-0,6,main]
    Thread[DestroyJavaVM,5,main]
    java.lang.ThreadGroup[name=Ruby Threads#11483240,maxpri=10]
----------------------------------------
In action listener:
Thread name: AWT-EventQueue-0
Is event dispatch thread: true
java.lang.ThreadGroup[name=main,maxpri=10]
    Thread[AWT-EventQueue-0,6,main]
    Thread[DestroyJavaVM,5,main]
    java.lang.ThreadGroup[name=Ruby Threads#11483240,maxpri=10]

在调用SwingUtilities.invokeLater（）之前，EDT不存在在SwingUtilities.invokeLater（）之后存在EDT并且它与当前线程不同。在JFrame构造函数和JButton动作事件侦听器中，EDT是当前线程。

另一个脚本不使用SwingUtilities.invokeLater（）：

java_import javax.swing.JFrame
java_import javax.swing.SwingUtilities
java_import java.awt.Dimension
java_import javax.swing.JButton
JavaThread = java.lang.Thread

puts '----------------------------------------'
puts 'Before JFrame.new():'
puts "Thread name: #{JavaThread.current_thread.name}"
puts "Is event dispatch thread: #{SwingUtilities.event_dispatch_thread?}"
JavaThread.current_thread.thread_group.list

frame = JFrame.new()

frame.set_default_close_operation(JFrame::EXIT_ON_CLOSE)
frame.set_preferred_size(Dimension.new(400, 300))

button = JButton.new('Button')
button.add_action_listener do |event|
  puts '----------------------------------------'
  puts 'In action listener:'
  puts "Thread name: #{JavaThread.current_thread.name}"
  puts "Is event dispatch thread: #{SwingUtilities.event_dispatch_thread?}"
  JavaThread.current_thread.thread_group.list
end

frame.get_content_pane.add(button)
frame.pack()

puts '----------------------------------------'
puts 'Before JFrame.setVisible():'
puts "Thread name: #{JavaThread.current_thread.name}"
puts "Is event dispatch thread: #{SwingUtilities.event_dispatch_thread?}"
JavaThread.current_thread.thread_group.list

frame.set_visible(true)

输出结果为：

----------------------------------------
Before JFrame.new():
Thread name: main
Is event dispatch thread: false
java.lang.ThreadGroup[name=main,maxpri=10]
    Thread[main,5,main]
    Thread[Ruby-0-JIT-1,1,main]
    java.lang.ThreadGroup[name=Ruby Threads#11483240,maxpri=10]
----------------------------------------
Before JFrame.setVisible():
Thread name: main
Is event dispatch thread: false
java.lang.ThreadGroup[name=main,maxpri=10]
    Thread[main,5,main]
    Thread[Ruby-0-JIT-1,1,main]
    Thread[AWT-EventQueue-0,6,main]
    java.lang.ThreadGroup[name=Ruby Threads#11483240,maxpri=10]
----------------------------------------
In action listener:
Thread name: AWT-EventQueue-0
Is event dispatch thread: true
java.lang.ThreadGroup[name=main,maxpri=10]
    Thread[AWT-EventQueue-0,6,main]
    Thread[DestroyJavaVM,5,main]
    java.lang.ThreadGroup[name=Ruby Threads#11483240,maxpri=10]

在JFrame构造函数不是当前线程之后创建EDT。在JButton事件监听器中，EDT是当前线程。

Answer 1

将JRuby视为任何其他JVM语言......没有特别注意内置的Swing / AWT约定 - 只有＆＃34; new＆＃34;用于编写Swing GUI的语法。因此，就像你在Java中一样关心EDT。

JRuby和Swing Event Dispatch Thread

1 个答案: