WindowListener无法按预期工作 [英] WindowListener does not work as expected

问题描述

我希望我的GUI在出现JOptionPane时进行一些检查。
因为我找不到任何其他方式，我虽然每次应用程序窗口失去焦点时都可以执行这些操作（它只是检查字符串）。出于这个原因，我在我的JFrame上添加了以下代码：

I want my GUI to make some checks when a JOptionPane appears. Because I can't find any other way, I though I can do those each time the application window loses focus(its just checking a string). For that reason I added the following code on my JFrame:

appFrame.addWindowListener(new WindowAdapter() {

            @Override
            public void windowLostFocus(WindowEvent e) {
                System.out.println("Focus Lost");

            }
            @Override
            public void windowClosing(WindowEvent e) {
                //some other stuff here that work
            }
});

窗口关闭监听器工作正常。虽然当JFrame没有集中时没有任何反应。每次从JFrame切换到其他窗口时，不应该打印Focus Lost吗？此外，当显示JOptionPane时会触发此方法吗？

The window closing listener works fine. Although when the JFrame isn't focused nothing happens. Shouldn't "Focus Lost" be printed each time I switch from JFrame to some other window? Also, will this method be triggered when a JOptionPane is shown?

推荐答案

我不打算讨论你为什么这么做你正在做什么，但由于以下原因它没有按预期工作：

I'm not going to go into why you are doing what you are doing, but it is not working as you expect for the following reason:

WindowAdapter 是一个便利类，因此你可以创建一个监听器并为多种类型的事件注册。您只为一组事件注册了它，您还需要通过以下方式注册焦点事件： Window.addWindowFocusListener（）

WindowAdapter adapter = new WindowAdapter() {
        @Override
        public void windowLostFocus(WindowEvent e) {
            System.out.println("Focus Lost");
        }
        @Override
        public void windowClosing(WindowEvent e) {
            //some other stuff here that work
        }
    };
appFrame.addWindowListener(adapter);
appFrame.addWindowFocusListener(adapter);

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