Question

我正在创建一个简单的计算器，它会在文本字段中添加两个值，然后在按下按钮时在第三个文本字段中显示总和。但是，当我按下按钮时没有任何反应，我无法弄清楚出了什么问题。我没有得到任何错误消息，程序编译按钮似乎什么也没做。

import javafx.application.*;
import javafx.geometry.*;
import javafx.scene.*;
import javafx.stage.*;
import javafx.scene.layout.*;
import javafx.scene.control.*;
import javafx.event.*;


public class Calculator extends Application{

private TextField sumField;
private TextField firstVField;
private TextField secondVField;

public void start(Stage myStage){
    myStage.setTitle("Simple Calculator");

    GridPane rootNode = new GridPane();
    rootNode.setPadding(new Insets(30));
    rootNode.setHgap(5);
    rootNode.setVgap(5);

    Scene myScene = new Scene(rootNode, 350,250);

    Label firstVLabel = new Label("First Value:");
    Label secondVLabel = new Label("Second Value:");
    Label sumLabel = new Label("Sum:");


    TextField firstVField = new TextField();
    TextField secondVField = new TextField();
    TextField sumField = new TextField();


    sumField.setEditable(false);

    Button calculate = new Button("Calculate");

    rootNode.add(firstVLabel, 0, 0);
    rootNode.add(firstVField, 1, 0);
    rootNode.add(secondVLabel, 0, 1);
    rootNode.add(secondVField, 1, 1);
    rootNode.add(sumLabel, 0, 2);
    rootNode.add(sumField, 1, 2);
    rootNode.add(calculate, 1, 3);

    myStage.setScene(myScene);
    myStage.setResizable(false);
    myStage.show();

}

class ButtonHandler implements EventHandler<ActionEvent>{

    public void handle(ActionEvent e) {
        int sum = (int)firstVField.getText() + (int)secondVField.getText();
        sumField.setText(Integer.toString(sum));

    }
}

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

}

Answer 1

您忘了将ButtonHandler与calculate按钮相关联

calculate.setOnAction(new ButtonHandler());

JavaFX按钮侦听器无法正常工作

1 个答案: