Question

我需要为桌面应用程序创建一个弹出窗口。我是通过TCP从客户端到服务器的通信，我希望窗口在等待服务器响应时覆盖主界面。基本上是“请等待回应”的项目。

我已经能够生成一个窗口并在响应具有验证性质时结束，但我无法在舞台上显示任何项目。

Label lblSecondWindow = new Label("This is the second window");
lblSecondWindow.setAlignment(Pos.TOP_LEFT);
lblSecondWindow.autosize();
lblSecondWindow.setVisible(true);
StackPane secondLayout = new StackPane();
secondLayout.getChildren().add(lblSecondWindow);
Scene secondScene = new Scene(secondLayout, 300, 200);
Stage secondStage = new Stage();
secondStage.setTitle("Please Wait");
secondStage.setScene(secondScene);
secondStage.show();

出现一个窗口，但标签无处可寻。如果可能的话，我愿意用另一种方式来解决这个问题，因为我在这个问题上失去的头发比我愿意承认的要多。

Answer 1

您使用的代码不包含错误。但是，我确定我知道您的错误：您通过在UI线程上进行服务器通信来阻止UI线程。您必须将其移动到另一个线程才能使其正常工作。

我可以使用以下代码重现您的错误：

Label lblSecondWindow = new Label("This is the second window");
lblSecondWindow.setAlignment(Pos.TOP_LEFT);
lblSecondWindow.autosize();
lblSecondWindow.setVisible(true);
StackPane secondLayout = new StackPane();
secondLayout.getChildren().add(lblSecondWindow);
Scene secondScene = new Scene(secondLayout, 300, 200);
Stage secondStage = new Stage();
secondStage.setTitle("Please Wait");
secondStage.setScene(secondScene);
secondStage.show();
try {
    Thread.sleep(1000);
} catch (InterruptedException ex) {
} // Stands for expensive operation (the whole try catch)
secondStage.close();

但不是如果我注释掉try-catch块，代表您的服务器通信，secondStage.close();。

可以像这样重写代码以使其工作：

Label lblSecondWindow = new Label("This is the second window");
lblSecondWindow.setAlignment(Pos.TOP_LEFT);
lblSecondWindow.autosize();
lblSecondWindow.setVisible(true);
StackPane secondLayout = new StackPane();
secondLayout.getChildren().add(lblSecondWindow);
Scene secondScene = new Scene(secondLayout, 300, 200);
final Stage secondStage = new Stage();
secondStage.setTitle("Please Wait");
secondStage.setScene(secondScene);
secondStage.show();
new Thread() {
    @Override
    public void run() {
        try {
            Thread.sleep(1000);
        } catch (InterruptedException ex) {
        } // Stands for expensive operation (the whole try catch)
        Platform.runLater(new Runnable() {

            @Override
            public void run() {
                // UI changes have to be done from the UI thread
                secondStage.close();
            }
        });
    }
}.start();

在JavaFX中生成一个子窗口

1 个答案: