java - 使用线程时出现 StackOverflowError

Question

我正在开发一个带有用户界面的弹丸运动模拟程序。我收到 StackOverflow 错误，它似乎发生在我尝试为我的按钮和文本字段创建 Action 监听器的地方。我了解 stackoverflow 错误与永不退出的递归有关，但我在我的代码中看不到发生这种情况的位置。

我决定在我的程序中使用线程，因为耗时的 Activity 让我的程序变慢了。所以我有一个线程来处理模拟的所有计算。

代码很长，但这里是它的结构。

 public class SimulationGUI implements ActionListener, Runnable
 {
      //Create object references for window, panels, text fields, buttons, and labels. 

      SimulationGUI() 
      {
           //Here I instantiate all my buttons, textfields, labels, 
           //and basically set up the user interface.

           createListeners(); //This calls a method that creates my action listeners
      }   

      public void actionPerformed(ActionEvent e)
       {
           Thread thread = new Thread(this);
           thread.start();  // this calls the method run()
      }

      public void run()
      {
           //Here, I get the text for the variables  
           //calculations are performed for the projectile motion
           //I also edit three top level text fields using .setText()
      } 

      public void createListeners()
      {
           //Add action listeners for each text field
           ActionListener angleList = new SimulationGUI(); 
           angleText.addActionListener(angleList); 

           ..... 
      } 

      public static void main(String[] args)
      {
           new SimulationGUI(); 
      }

 }

我猜我必须在新线程中创建和添加 Action 监听器，但我不完全确定。以下是我收到的错误:

 Exception in thread "main" java.lang.StackOverflowError
     at java.awt.Insets.<init>(Unknown Source)
     at sun.awt.windows.WToolkit.getScreenInsets(Native Method)
     at sun.awt.windows.WToolkit.getScreenInsets(Unknown Source)
     at java.awt.Window.init(Unknown Source)
     at java.awt.Window.<init>(Unknown Source)
     at java.awt.Frame.<init>(Unknown Source)
     at javax.swing.JFrame.<init>(Unknown Source)
     at SimulationGUI.<init>(SimulationGUI.java:24)
     at SimulationGUI.createListeners(SimulationGUI.java:211)
     at SimulationGUI.<init>(SimulationGUI.java:124)
     at SimulationGUI.createListeners(SimulationGUI.java:211)
     at SimulationGUI.<init>(SimulationGUI.java:124)
     at SimulationGUI.createListeners(SimulationGUI.java:211)
     at SimulationGUI.<init>(SimulationGUI.java:124)
     at SimulationGUI.createListeners(SimulationGUI.java:211)
     at SimulationGUI.<init>(SimulationGUI.java:124)
     at SimulationGUI.createListeners(SimulationGUI.java:211)
     at SimulationGUI.<init>(SimulationGUI.java:124)
     at SimulationGUI.createListeners(SimulationGUI.java:211)
     at SimulationGUI.<init>(SimulationGUI.java:124)
     at SimulationGUI.createListeners(SimulationGUI.java:211)
 .....

Answer 1

是的，您已经陷入了无限循环。这是导致问题的代码部分:

SimulationGUI() 
{
    createListeners();
}

public void createListeners()
{
    ActionListener angleList = new SimulationGUI();
    angleText.addActionListener(angleList);
}

看看有什么问题？这两种方法都无条件地相互调用，并且在剩下的时间内(或至少直到堆栈已满)都将这样做。证据在堆栈跟踪中:

at SimulationGUI.<init>(SimulationGUI.java:24)
at SimulationGUI.createListeners(SimulationGUI.java:211)
at SimulationGUI.<init>(SimulationGUI.java:124)
at SimulationGUI.createListeners(SimulationGUI.java:211)
at SimulationGUI.<init>(SimulationGUI.java:124)
at SimulationGUI.createListeners(SimulationGUI.java:211)
at SimulationGUI.<init>(SimulationGUI.java:124)
at SimulationGUI.createListeners(SimulationGUI.java:211)
at SimulationGUI.<init>(SimulationGUI.java:124)
at SimulationGUI.createListeners(SimulationGUI.java:211)
at SimulationGUI.<init>(SimulationGUI.java:124)
at SimulationGUI.createListeners(SimulationGUI.java:211)
at SimulationGUI.<init>(SimulationGUI.java:124)
at SimulationGUI.createListeners(SimulationGUI.java:211)

看看这些方法是如何返回并相互调用的？您可能想要更像这样的东西:

SimulationGUI() 
{
    createListeners();
}

public void createListeners()
{
    angleText.addActionListener(this);
}