JavaFX - onCloseRequest() 否决了我的 boolean 语句

Question

在我的程序的 GUI 中，我有一行:

window.setOnCloseRequest(closeProgram());

只要用户按下窗口框架上的 X 按钮(不是我制作的按钮，而是每个 GUI 应用程序上的默认按钮)，就会运行此函数。

showWarningWindow 是一个 boolean 方法，它显示有关关闭程序的确认窗口。如果为 true，它将运行 Platform.exit();

我 100% 确定我的 showWarningWindow() 方法返回 false，但应用程序仍然关闭。这是为什么？我怎样才能阻止它发生？

/**
 * This method is called when the user wishes to close the program.
 */
private void closeProgram()
{
    if (logic.unsavedChangesExist())
    {
        if (showWarningWindow("You currently have unsaved changes made to the database."
                + "\nAre you sure you would like to exit without saving?"))
        {
            Platform.exit();
        }
    }
}

Answer 1

如documentation中所示,

The installed event handler can prevent window closing by consuming the received event.

所以你需要

window.setOnCloseRequest(event -> closeProgram(event));

和

private void closeProgram(WindowEvent event)
{
    if (logic.unsavedChangesExist())
    {
        if (showWarningWindow("You currently have unsaved changes made to the database."
                + "\nAre you sure you would like to exit without saving?"))
        {
            Platform.exit();
        } else {
            event.consume();
        }
    }
}

如果没有这个，无论 showWarningWindow 的返回值如何，您的窗口都将关闭。如果它恰好是最后一个打开的窗口，并且 Platform.isImplicitExit() 返回 true(默认值)，则 the application will exit .