JavaFX按钮不是先响应第二次点击 [英] JavaFX button reacting on second click not first

问题描述

我正在尝试在JavaFX中创建我的第一个应用程序，我遇到了一个调用方法的Button问题（例如打开另一个窗口） - 我总是要点击它两次才能触发操作。

I am trying to create my very first application in JavaFX and I have a problem with Button that calls a method (for example to open another window) - I always have to click it twice in order to trigger action.

这是来自Controller的代码：

Here's my code from the Controller:

import javafx.fxml.FXML;
import javafx.scene.control.Button;

public class ControllerSignIn {

    @FXML
    private Button forgot;
    @FXML
    private Button back;
    @FXML
    private Button signin;

    public void forgetPasswordClicked() {
        forgot.setOnAction(e -> ForgotPassword.setUpWindow()); //works on 2nd click
    }

    public void backClicked() {
        back.setOnAction(e -> ForgotPassword.closeWindow()); //works on 2nd click
    }

    public void signInClicked() {
        System.out.println("Sign In CLICKED"); //works on first click
    }
}

我的方法在这里实现：

import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Modality;
import javafx.stage.Stage;
import java.io.IOException;

public class ForgotPassword {

    static Stage window;
    static Scene scene;
    static Parent root;

    private static void loadFXML() {
        try {
            root = FXMLLoader.load(ForgotPassword.class.getResource("ForgotPassword.fxml"));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void setUpWindow() {
        loadFXML();

        scene = new Scene(root);
        scene.getStylesheets().add("signin/SignIn.css");

        window = new Stage();
        window.initModality(Modality.APPLICATION_MODAL);
        window.setTitle("Forgot Password?");
        window.setScene(scene);
        window.showAndWait();
    }

    public static void closeWindow() {
        window.close();
    }
}

推荐答案

最可能你的FXML中有以下内容：

Most likely you have the following in your FXML:

<Button fx:id="forgot" onAction="#forgetPasswordClicked" />

这使您的按钮忘记调用您的方法 forgetPasswordClicked（）。但是，当您单击按钮时，不是定义要执行的逻辑，而是第一次说：单击此按钮时，在我的按钮上放置一个动作事件 call setUpWindow（）

This makes your button forgot call your method forgetPasswordClicked(). But instead of defining your logic to be executed when your button is clicked, the first time you say: "When this button is clicked, place an action event on my button which will call setUpWindow()"

forgot.setOnAction(e -> ForgotPassword.setUpWindow());

因此，首次点击设置按钮的逻辑。第二次点击，实际执行它。要解决此问题，请立即使用您的逻辑：

Therefore, your first click "sets up" the logic of your button. The second click, actually executes it. To solve this, either immediately use your logic as such:

public void forgetPasswordClicked() {
    ForgotPassword.setUpWindow();
}

或者不定义fxml中要调用的方法，并移动按钮的初始化（设置动作监听器）如下所示：

or don't define the method to be called in your fxml, and move the initialization of your button (setting the action listener) to your initialization as following:

public class ControllerSignIn implements Initializable {
    @FXML
    private Button forgot;
    @FXML
    private Button back;

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        forgot.setOnAction(e -> ForgotPassword.setUpWindow());
        back.setOnAction(e -> ForgotPassword.closeWindow());
    }
}

这也是你的原因signInClicked（）方法从第一次单击开始工作，因为它实际上执行逻辑而不是首先设置处理程序。

This is also why your signInClicked() method works from the first click, because it actually executes the logic instead of setting up the handler first.

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