在edt中更新swing组件(Updating swing components within edt)

 如果我理解正确，那么当我创建GUI swing组件时，例如我有这个： 
 
public class frameExample extends JFrame{
    public frameExample(){
    //Here adding bunch if components
    setVisible(true);
    }
}
 
 因此，只要我不调用setVisible方法，就会从创建实例的线程中创建组件。 所以如果在我的主要方法的类中写： 
 
JFrame test=new frameExample();
 
 和我sysout 
 
Thread.currentThread.getName(); 
 
 在setExample的构造函数中，在setVisible之前，我应该得到：main。 
 
 之后，创建和维护swing元素的责任被传递给event-dispatch-thread，因为它不是线程安全的，所以每个组件的添加/删除/修改都应该在EDT线程中完成。 
 
 所以我应该将我的setVisible作为构造函数中的最后一行代码，或者单独调用它。 
 
 据我所知，所有的事件都是通过EDT进行的。 因此，如果我在例如actionPerformed方法中创建一个新组件，它应该没问题。 
 
 另外，如果我将runnable实例传递给invokeLater或invokeAndWait，那么所有run（）方法都将由EDT完成。 
 
 所以这就是为什么我很困惑。 
 
 我做了这个代码： 
 
public class GUI extends JFrame {


JButton btn = new JButton("Change");
JMenuBar m = new JMenuBar();

public GUI() {
    super("Test");
    setSize(400, 400);
    setDefaultCloseOperation(EXIT_ON_CLOSE);

    m.add(new JMenu("menu"));
    add(m, BorderLayout.NORTH);

    add(btn, BorderLayout.SOUTH);
    System.out.println("Current thread: before setVisible "+Thread.currentThread().getName());

    setVisible(true);

    System.out.println("Current thread: after setVisible "+Thread.currentThread().getName());
    btn.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {

            add(new JButton("testbtn1"), BorderLayout.EAST);
            add(new JButton("testbtn2"));
            System.out.println("Current thread: "+Thread.currentThread().getName());


            new Thread(new Runnable() {

                @Override
                public void run() {
                    // TODO Auto-generated method stub
                    for (int i = 0; i < 1E8; i++) {
                        Math.sin(5.0);
                    }
                    System.out.println("Current thread: "+Thread.currentThread().getName());
                }
            }).start();

        }
    });
}
 
 } 
 
 所以在我的anonim类中，我在EDT中添加了两个按钮，但是在我调整它之后组件没有添加到我的框架中（这迫使edt更新其组件???这是什么原因？） 。 
 
 因此，即使在edt中我也不会得到我的新组件，但是当我在edt之外创建一个随机线程并使其更改一些gui元素属性（例如setText）在edt之外工作正常。 
 
 所以我的第一个问题是：为什么我的组件没有在edt中更新，以及为什么它们在调整大小后可见 
 
 第二个：为什么我可以对edt外的摆动组件进行更改，一切正常？ 这只是一个随机的线程行为，例如，没有同步块的情况下工作正常，但是当你重新运行程序时，它会因为缺乏同步而最终崩溃。 

If I understand correctly then when I create GUI swing components, for example I have this:
 
public class frameExample extends JFrame{
    public frameExample(){
    //Here adding bunch if components
    setVisible(true);
    }
}
 
So as long as I don't call the setVisible method the components are being made from the thread the instance was created. So if in a class where i have my main method write:
 
JFrame test=new frameExample();
 
and I sysout 
 
Thread.currentThread.getName(); 
 
in the constructor in frameExample just before setVisible I should get: main.
 
After that the responsibility of creating and maintaining swing elements are passed to the event-dispatch-thread and because it is not thread safe every component add/remove/modify should be done within the EDT thread.
 
So I should place my setVisible as the last line of code in my constructor, or call it separately.
 
As I understand all event listening goes through the EDT. So if I create a new component within for example an actionPerformed method it should do fine.
 
Also if I pass a runnable instance to invokeLater or invokeAndWait then all the run() method will be done by the EDT.
 
So here is why I'm confused.
 
I made this code:
 
public class GUI extends JFrame {


JButton btn = new JButton("Change");
JMenuBar m = new JMenuBar();

public GUI() {
    super("Test");
    setSize(400, 400);
    setDefaultCloseOperation(EXIT_ON_CLOSE);

    m.add(new JMenu("menu"));
    add(m, BorderLayout.NORTH);

    add(btn, BorderLayout.SOUTH);
    System.out.println("Current thread: before setVisible "+Thread.currentThread().getName());

    setVisible(true);

    System.out.println("Current thread: after setVisible "+Thread.currentThread().getName());
    btn.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {

            add(new JButton("testbtn1"), BorderLayout.EAST);
            add(new JButton("testbtn2"));
            System.out.println("Current thread: "+Thread.currentThread().getName());


            new Thread(new Runnable() {

                @Override
                public void run() {
                    // TODO Auto-generated method stub
                    for (int i = 0; i < 1E8; i++) {
                        Math.sin(5.0);
                    }
                    System.out.println("Current thread: "+Thread.currentThread().getName());
                }
            }).start();

        }
    });
}
 
}
 
So in my anonim class where I add the two buttons im in the EDT, but the components are not added to my frame just after i resize it (which forces the edt to update its components??? what is the reason for this?).
 
So i dont get my new components even within edt, however when i create a random thread outside edt and make it change some gui element property (for example setText) in just works fine outside the edt.
 
So my first question is: why my components are not updated within edt and why they are visible after resize
 
second one: why can i make changes to swing components outside edt and everything works fine? Is this just random thread behvior where for example things just work fine without sync block but when you rerun you program at some point it will eventually crash because the lack of sync.

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