Java 如何从其他类获取对节点的引用？

有没有简单的方法可以从其他类获取对stage控件的引用？除了Delphi之外，它似乎在每个基于GUI的框架中都是一个问题。如果只有

Controller

或

Main

类是静态的

这是我的密码：

Controller.java：

package sample;

import javafx.fxml.*;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;

public class Controller {

    @FXML
    private Button algorithms;

    @FXML
    private Button settings;

    @FXML
    private Button run;

    @FXML
    public TextArea console; // I want access that node from class named 'Utils'

    @FXML
    void initialize() { }

    public Controller () { }

    @FXML
    private void onRun() {
        Utility.get().runBench();
    }

    @FXML
    private void onSettings() {
        console.appendText("I am opening settings...");
    }

    @FXML
    private void onAlgorithm() {
        console.appendText("I am opening list of Algorithms...");
    }
}

package sample;

import sample.Algorithms.BubbleSort;

import java.util.*;


// Singleton
public class Utility {
    private static Utility ourInstance = new Utility();

    public static Utility get() {
        return ourInstance;
    }

    private Utility() {
        listOfAlgorithms.add(new BubbleSort(howManyN));
    }

    List<Algorithm> listOfAlgorithms = new LinkedList<>();
    Long howManyN = 999L;

    public void runBench() {
        for (Algorithm a: listOfAlgorithms) {
            double start = System.nanoTime();
            a.run();
            double end = System.nanoTime();
            double result = end - start;
            System.out.println(
//            console.appendText(  // Accessing like that would be ideal
                    "Algorithm: " + a.getClass().getName() + "\n" +
                    "For N = " + a.getN() + " time is: " + result
            );
        }
    }
}

package sample;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;


public class Main extends Application {

    final String APP_NAME = "SortAll 2";
    final String RES_PATH = "../resources/scene.fxml";

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

    @Override
    public void start(Stage primaryStage) throws Exception{
        Parent root = FXMLLoader.load(getClass().getResource(RES_PATH));
        primaryStage.setTitle(APP_NAME);
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }
}

 public void runBench(TextArea console) {
    for (Algorithm a: listOfAlgorithms) {
        double start = System.nanoTime();
        a.run();
        double end = System.nanoTime();
        double result = end - start;
        System.out.println(
        console.appendText(
                "Algorithm: " + a.getClass().getName() + "\n" +
                "For N = " + a.getN() + " time is: " + result
        );
    }
}

@FXML
private void onRun() {
    Utility.get().runBench(console);
}

Utils.java：

package sample;

import javafx.fxml.*;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;

public class Controller {

    @FXML
    private Button algorithms;

    @FXML
    private Button settings;

    @FXML
    private Button run;

    @FXML
    public TextArea console; // I want access that node from class named 'Utils'

    @FXML
    void initialize() { }

    public Controller () { }

    @FXML
    private void onRun() {
        Utility.get().runBench();
    }

    @FXML
    private void onSettings() {
        console.appendText("I am opening settings...");
    }

    @FXML
    private void onAlgorithm() {
        console.appendText("I am opening list of Algorithms...");
    }
}

package sample;

import sample.Algorithms.BubbleSort;

import java.util.*;


// Singleton
public class Utility {
    private static Utility ourInstance = new Utility();

    public static Utility get() {
        return ourInstance;
    }

    private Utility() {
        listOfAlgorithms.add(new BubbleSort(howManyN));
    }

    List<Algorithm> listOfAlgorithms = new LinkedList<>();
    Long howManyN = 999L;

    public void runBench() {
        for (Algorithm a: listOfAlgorithms) {
            double start = System.nanoTime();
            a.run();
            double end = System.nanoTime();
            double result = end - start;
            System.out.println(
//            console.appendText(  // Accessing like that would be ideal
                    "Algorithm: " + a.getClass().getName() + "\n" +
                    "For N = " + a.getN() + " time is: " + result
            );
        }
    }
}

package sample;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;


public class Main extends Application {

    final String APP_NAME = "SortAll 2";
    final String RES_PATH = "../resources/scene.fxml";

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

    @Override
    public void start(Stage primaryStage) throws Exception{
        Parent root = FXMLLoader.load(getClass().getResource(RES_PATH));
        primaryStage.setTitle(APP_NAME);
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }
}

 public void runBench(TextArea console) {
    for (Algorithm a: listOfAlgorithms) {
        double start = System.nanoTime();
        a.run();
        double end = System.nanoTime();
        double result = end - start;
        System.out.println(
        console.appendText(
                "Algorithm: " + a.getClass().getName() + "\n" +
                "For N = " + a.getN() + " time is: " + result
        );
    }
}

@FXML
private void onRun() {
    Utility.get().runBench(console);
}

---

嗯，您不能将console作为runBench（）参数传递吗

Utility.java：

package sample;

import javafx.fxml.*;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;

public class Controller {

    @FXML
    private Button algorithms;

    @FXML
    private Button settings;

    @FXML
    private Button run;

    @FXML
    public TextArea console; // I want access that node from class named 'Utils'

    @FXML
    void initialize() { }

    public Controller () { }

    @FXML
    private void onRun() {
        Utility.get().runBench();
    }

    @FXML
    private void onSettings() {
        console.appendText("I am opening settings...");
    }

    @FXML
    private void onAlgorithm() {
        console.appendText("I am opening list of Algorithms...");
    }
}

package sample;

import sample.Algorithms.BubbleSort;

import java.util.*;


// Singleton
public class Utility {
    private static Utility ourInstance = new Utility();

    public static Utility get() {
        return ourInstance;
    }

    private Utility() {
        listOfAlgorithms.add(new BubbleSort(howManyN));
    }

    List<Algorithm> listOfAlgorithms = new LinkedList<>();
    Long howManyN = 999L;

    public void runBench() {
        for (Algorithm a: listOfAlgorithms) {
            double start = System.nanoTime();
            a.run();
            double end = System.nanoTime();
            double result = end - start;
            System.out.println(
//            console.appendText(  // Accessing like that would be ideal
                    "Algorithm: " + a.getClass().getName() + "\n" +
                    "For N = " + a.getN() + " time is: " + result
            );
        }
    }
}

package sample;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;


public class Main extends Application {

    final String APP_NAME = "SortAll 2";
    final String RES_PATH = "../resources/scene.fxml";

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

    @Override
    public void start(Stage primaryStage) throws Exception{
        Parent root = FXMLLoader.load(getClass().getResource(RES_PATH));
        primaryStage.setTitle(APP_NAME);
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }
}

 public void runBench(TextArea console) {
    for (Algorithm a: listOfAlgorithms) {
        double start = System.nanoTime();
        a.run();
        double end = System.nanoTime();
        double result = end - start;
        System.out.println(
        console.appendText(
                "Algorithm: " + a.getClass().getName() + "\n" +
                "For N = " + a.getN() + " time is: " + result
        );
    }
}

@FXML
private void onRun() {
    Utility.get().runBench(console);
}

及

Controller.java：

package sample;

import javafx.fxml.*;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;

public class Controller {

    @FXML
    private Button algorithms;

    @FXML
    private Button settings;

    @FXML
    private Button run;

    @FXML
    public TextArea console; // I want access that node from class named 'Utils'

    @FXML
    void initialize() { }

    public Controller () { }

    @FXML
    private void onRun() {
        Utility.get().runBench();
    }

    @FXML
    private void onSettings() {
        console.appendText("I am opening settings...");
    }

    @FXML
    private void onAlgorithm() {
        console.appendText("I am opening list of Algorithms...");
    }
}

package sample;

import sample.Algorithms.BubbleSort;

import java.util.*;


// Singleton
public class Utility {
    private static Utility ourInstance = new Utility();

    public static Utility get() {
        return ourInstance;
    }

    private Utility() {
        listOfAlgorithms.add(new BubbleSort(howManyN));
    }

    List<Algorithm> listOfAlgorithms = new LinkedList<>();
    Long howManyN = 999L;

    public void runBench() {
        for (Algorithm a: listOfAlgorithms) {
            double start = System.nanoTime();
            a.run();
            double end = System.nanoTime();
            double result = end - start;
            System.out.println(
//            console.appendText(  // Accessing like that would be ideal
                    "Algorithm: " + a.getClass().getName() + "\n" +
                    "For N = " + a.getN() + " time is: " + result
            );
        }
    }
}

package sample;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;


public class Main extends Application {

    final String APP_NAME = "SortAll 2";
    final String RES_PATH = "../resources/scene.fxml";

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

    @Override
    public void start(Stage primaryStage) throws Exception{
        Parent root = FXMLLoader.load(getClass().getResource(RES_PATH));
        primaryStage.setTitle(APP_NAME);
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }
}

 public void runBench(TextArea console) {
    for (Algorithm a: listOfAlgorithms) {
        double start = System.nanoTime();
        a.run();
        double end = System.nanoTime();
        double result = end - start;
        System.out.println(
        console.appendText(
                "Algorithm: " + a.getClass().getName() + "\n" +
                "For N = " + a.getN() + " time is: " + result
        );
    }
}

@FXML
private void onRun() {
    Utility.get().runBench(console);
}

---

嗯，您不能将console作为runBench（）参数传递吗

Utility.java：

package sample;

import javafx.fxml.*;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;

public class Controller {

    @FXML
    private Button algorithms;

    @FXML
    private Button settings;

    @FXML
    private Button run;

    @FXML
    public TextArea console; // I want access that node from class named 'Utils'

    @FXML
    void initialize() { }

    public Controller () { }

    @FXML
    private void onRun() {
        Utility.get().runBench();
    }

    @FXML
    private void onSettings() {
        console.appendText("I am opening settings...");
    }

    @FXML
    private void onAlgorithm() {
        console.appendText("I am opening list of Algorithms...");
    }
}

package sample;

import sample.Algorithms.BubbleSort;

import java.util.*;


// Singleton
public class Utility {
    private static Utility ourInstance = new Utility();

    public static Utility get() {
        return ourInstance;
    }

    private Utility() {
        listOfAlgorithms.add(new BubbleSort(howManyN));
    }

    List<Algorithm> listOfAlgorithms = new LinkedList<>();
    Long howManyN = 999L;

    public void runBench() {
        for (Algorithm a: listOfAlgorithms) {
            double start = System.nanoTime();
            a.run();
            double end = System.nanoTime();
            double result = end - start;
            System.out.println(
//            console.appendText(  // Accessing like that would be ideal
                    "Algorithm: " + a.getClass().getName() + "\n" +
                    "For N = " + a.getN() + " time is: " + result
            );
        }
    }
}

package sample;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;


public class Main extends Application {

    final String APP_NAME = "SortAll 2";
    final String RES_PATH = "../resources/scene.fxml";

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

    @Override
    public void start(Stage primaryStage) throws Exception{
        Parent root = FXMLLoader.load(getClass().getResource(RES_PATH));
        primaryStage.setTitle(APP_NAME);
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }
}

 public void runBench(TextArea console) {
    for (Algorithm a: listOfAlgorithms) {
        double start = System.nanoTime();
        a.run();
        double end = System.nanoTime();
        double result = end - start;
        System.out.println(
        console.appendText(
                "Algorithm: " + a.getClass().getName() + "\n" +
                "For N = " + a.getN() + " time is: " + result
        );
    }
}

@FXML
private void onRun() {
    Utility.get().runBench(console);
}

及

Controller.java：

package sample;

import javafx.fxml.*;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;

public class Controller {

    @FXML
    private Button algorithms;

    @FXML
    private Button settings;

    @FXML
    private Button run;

    @FXML
    public TextArea console; // I want access that node from class named 'Utils'

    @FXML
    void initialize() { }

    public Controller () { }

    @FXML
    private void onRun() {
        Utility.get().runBench();
    }

    @FXML
    private void onSettings() {
        console.appendText("I am opening settings...");
    }

    @FXML
    private void onAlgorithm() {
        console.appendText("I am opening list of Algorithms...");
    }
}

package sample;

import sample.Algorithms.BubbleSort;

import java.util.*;


// Singleton
public class Utility {
    private static Utility ourInstance = new Utility();

    public static Utility get() {
        return ourInstance;
    }

    private Utility() {
        listOfAlgorithms.add(new BubbleSort(howManyN));
    }

    List<Algorithm> listOfAlgorithms = new LinkedList<>();
    Long howManyN = 999L;

    public void runBench() {
        for (Algorithm a: listOfAlgorithms) {
            double start = System.nanoTime();
            a.run();
            double end = System.nanoTime();
            double result = end - start;
            System.out.println(
//            console.appendText(  // Accessing like that would be ideal
                    "Algorithm: " + a.getClass().getName() + "\n" +
                    "For N = " + a.getN() + " time is: " + result
            );
        }
    }
}

package sample;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;


public class Main extends Application {

    final String APP_NAME = "SortAll 2";
    final String RES_PATH = "../resources/scene.fxml";

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

    @Override
    public void start(Stage primaryStage) throws Exception{
        Parent root = FXMLLoader.load(getClass().getResource(RES_PATH));
        primaryStage.setTitle(APP_NAME);
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }
}

 public void runBench(TextArea console) {
    for (Algorithm a: listOfAlgorithms) {
        double start = System.nanoTime();
        a.run();
        double end = System.nanoTime();
        double result = end - start;
        System.out.println(
        console.appendText(
                "Algorithm: " + a.getClass().getName() + "\n" +
                "For N = " + a.getN() + " time is: " + result
        );
    }
}

@FXML
private void onRun() {
    Utility.get().runBench(console);
}

---

将对象传递给

runBench（）

方法，该方法描述了要对结果执行的操作。由于将结果封装为

字符串

，因此可以使用：

---

这与您发布的问题无关，但您几乎肯定需要在后台线程中执行

runBench（）

方法，因为执行该方法显然需要一些时间。如果这样做，则需要确保仅在FX应用程序线程上访问控制台。上述解决方案很容易修改以实现这一点（您的

runBench（…）

方法根本不需要更改）：

---

将对象传递给

runBench（）

方法，该方法描述了要对结果执行的操作。由于将结果封装为

字符串

，因此可以使用：

---

这与您发布的问题无关，但您几乎肯定需要在后台线程中执行

runBench（）

方法，因为执行该方法显然需要一些时间。如果这样做，则需要确保仅在FX应用程序线程上访问控制台。上述解决方案很容易修改以实现这一点（您的

runBench（…）

方法根本不需要更改）：

---

基本上不应该这样做：它违反了封装。控制器应该是唯一“了解”控件的对象。控制器是静态的没有任何意义，因为无法两次加载同一个FXML文件（两组UI控件只能有一个控制器）。如果确实要这样做，请将变量传递给util方法。基本上不应该这样做：这违反了封装。控制器应该是唯一“了解”控件的对象。控制器是静态的没有任何意义，因为无法两次加载同一个FXML文件（两组UI控件只能有一个控制器）。如果确实要这样做，请将变量传递给util方法。更好的方法是：传递

使用者

，以避免暴露UI控件（并保持灵活性等）。或者，您可以在runBench（）中构建并返回文本字符串，并将其直接附加到控制器方法中以实现更好的封装。编辑：您有更好的想法，先生：）我可以，但这不是正确的解决方案。也许我会在1000个类中有1000个方法。每次我都应该传递那个参数？如果我的阶段中有20个节点，我想访问它们。然后呢？@Barburka我在上面的评论中提出的建议有什么问题？我不能对直接回答（这里是newb）发表评论，但我可以在这里发表评论。非常基本的说法：Consumer是一个通用的函数接口，它允许您将方法作为参数传递，并在内部使用指定的类型参数执行。更好的做法是：传递

Consumer

，以避免暴露UI控件（并保持灵活性等）。或者您可以在runBench（）中构建并返回文本字符串并将其直接附加到控制器方法中，以实现更好的封装。编辑：你有更好的主意，先生：）我可以，但它不可能是正确的解决方案。也许我会在1000个类中有1000个方法。每次我都应该传递那个参数？如果我的阶段中有20个节点，我想访问它们。然后呢？@Barburka我在上面的评论中提出的建议有什么问题？我不能对直接回答（这里是newb）发表评论，但我可以在这里发表评论。非常基本的说法：Consumer是一个通用函数接口，它允许您将一个方法作为参数传递，并使用指定的类型参数在内部执行。@Barburka

Consumer

是一个具有单个抽象方法的接口，

public void accept（String value）

。方法引用

console:：appendText

（实际上，它不是这样工作的）创建了一个对象，该对象实现了与

public void accept（String value）{console.appendText（value）；}

的接口。现在我真正明白了，我做错了什么——类之间不应该相互了解。这是个好把戏consumer@Barburka

使用者

是一个具有单个抽象方法的接口，

公共void accept（字符串值）

。方法引用

console:：appendText

（实际上，它不是这样工作的）创建了一个对象，该对象实现了与

public void accept（String value）{console.appendText（value）；}

的接口。现在我真正明白了，我做错了什么——类之间不应该相互了解。这个消费者玩得很好