java - java gui方法/对象调用

Question

下面我有两个代码部分。第一个执行第二个我想要的操作。第一个代码编译并正常工作，第二个代码没有。我是 Java 新手，我认为我缺少有关如何调用另一个对象标签或微调器的基本知识。我想要一种方法来完成微调器状态更改中的所有事情。我对所有良好实践的实施持开放态度。我在 Eclipse 中使用窗口生成器。

package stackoverflowtestgui;

import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JSpinner;
import java.awt.BorderLayout;
import javax.swing.JLabel;
import javax.swing.event.ChangeListener;
import javax.swing.event.ChangeEvent;
import javax.swing.SpinnerNumberModel;        

public class TestGUI {

    private JFrame frame;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    TestGUI window = new TestGUI();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     */
    public TestGUI() {
        initialize();
    }

    /**
     * Initialize the contents of the frame.
     */
    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 450, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        JLabel lblTotal = new JLabel("total: "+total);
        lblTotal.setBounds(31, 38, 101, 14);
        frame.getContentPane().add(lblTotal);

        JSpinner spinner_2 = new JSpinner();
        JSpinner spinner_1 = new JSpinner();
        spinner_2.addChangeListener(new ChangeListener() {
            public void stateChanged(ChangeEvent e) {
                num1 = (double) spinner_1.getValue();
                num2 = (double) spinner_2.getValue();
                total = num1+num2;
                lblTotal.setText("total: "+total);
            }
        });
        spinner_2.setModel(new SpinnerNumberModel(new Double(0), null, null, new Double(1)));
        spinner_2.setBounds(31, 73, 30, 20);
        frame.getContentPane().add(spinner_2);


        spinner_1.addChangeListener(new ChangeListener() {
            public void stateChanged(ChangeEvent e) {
                num1 = (double) spinner_1.getValue();
                num2 = (double) spinner_2.getValue();
                total = num1+num2;
                lblTotal.setText("total: "+total);
            }
        });
        spinner_1.setModel(new SpinnerNumberModel(new Double(0), null, null, new Double(1)));
        spinner_1.setBounds(31, 104, 30, 20);
        frame.getContentPane().add(spinner_1);
    }
public double num1=0;
public double num2=0;
public double total=0;
}

这是我如何编写代码来做我想做的事情的一个例子:)

package stackoverflowtestgui;

import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JSpinner;
import java.awt.BorderLayout;
import javax.swing.JLabel;
import javax.swing.event.ChangeListener;
import javax.swing.event.ChangeEvent;
import javax.swing.SpinnerNumberModel;

public class TestGUI {

    private JFrame frame;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    TestGUI window = new TestGUI();
                    window.frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the application.
     */
    public TestGUI() {

        initialize();

    }

    /**
     * Initialize the contents of the frame.
     */
    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 450, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        lblTotal.setBounds(31, 38, 101, 14);
        frame.getContentPane().add(lblTotal);

        spinner_2.addChangeListener(new ChangeListener() {
            public void stateChanged(ChangeEvent e) {
                newmethod();
            }
        });

        spinner_2.setModel(new SpinnerNumberModel(new Double(0), null, null, new Double(1)));
        spinner_2.setBounds(31, 73, 72, 20);
        frame.getContentPane().add(spinner_2);


        spinner_1.addChangeListener(new ChangeListener() {
            public void stateChanged(ChangeEvent e) {
                newmethod();
            }
        });

        spinner_1.setModel(new SpinnerNumberModel(new Double(0), null, null, new Double(1)));
        spinner_1.setBounds(31, 104, 72, 20);
        frame.getContentPane().add(spinner_1);
    }
    protected void newmethod() {
        // TODO Auto-generated method stub
        num1 = (double) spinner_1.getValue();
        num2 = (double) spinner_2.getValue();
        total = num1+num2;
        lblTotal.setText("total: "+total);
    }
public double num1=0;
public double num2=0;
public double total=0;
public JSpinner spinner_2 = new JSpinner();
public JSpinner spinner_1 = new JSpinner();
public JLabel lblTotal = new JLabel("total: ");
}

标签： javauser-interfaceobjectmethods

Answer 1

您已在 initialize() 方法中将变量 spinner_1、spinner_2 和 lblTotal 声明为局部变量，因此它们在该方法之外不可见。它们应该是类的私有实例变量。