问刷新Java Swing中的现有窗口
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Stack Overflow用户

提问于 2018-06-03 18:46:25

回答 3查看 35关注 0票数 0

我正在尝试构建一个简单的Java Swing程序，您可以在其中输入您的名字和姓氏。

有两个按钮save和newDialog。save按钮将键入的名称保存到一个名为Person的类中。newDialog按钮打开一个新窗口，其中已打印保存的名称。我的问题是，我希望旧窗口也刷新并显示文本字段中保存的名称。我怎么能这么做？谢谢大家！

public class PersonFrame extends JFrame {   
    Person p = new Person();

    JTextField tf1 = new JTextField(Person.getForename());
    JTextField tf2 = new JTextField(Person.getSurname());
    JButton save = new JButton("Save");
    JButton newDialog = new JButton("NewDialog");

    public PersonFrame() {
        setTitle("Frame");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        JPanel myPanel = new JPanel();
        myPanel.setLayout(new GridLayout(3,2));
        myPanel.add(new JLabel("Forename"));
        myPanel.add(new JLabel("Surname"));
        myPanel.add(tf1);
        myPanel.add(tf2);
        save.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                p.setForename(tf1.getText());
                p.setSurname(tf2.getText());
            }
        });

        newDialog.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                SwingUtilities.updateComponentTreeUI(myPanel);
                PersonFrame personFrame = new PersonFrame();
                personFrame.pack();
                personFrame.setVisible(true);
            }
        });
        myPanel.add(save);
        myPanel.add(newDialog);
        this.getContentPane().add(myPanel);
    }

    public static void main(String[] args) throws InterruptedException {
        PersonFrame personFrame = new PersonFrame();
        personFrame.pack();
        personFrame.setVisible(true);
    }
}

个人类别：

public class Person {   
    private static String forename;
    private static String surname;

    public void setForename(String forename) {
        Person.forename = forename;
    }

    public void setSurname(String nachname) {
        Person.surname = nachname;
    }

    public static String getSurname() {
        if(Person.surname == null){
            return null;
        } else {
            return Person.surname;
        }
    }

    public static String getForename() {
        if(Person.forename == null) {
            return null;
        } else {
            return Person.forename;
        }
    }
}

java

回答 3

Stack Overflow用户

回答已采纳

发布于 2018-06-03 18:50:53

最好的方法是让Person类实现ChangeListener：https://docs.oracle.com/javase/7/docs/api/javax/swing/event/ChangeListener.html

然后，每一个使用个人信息的地方都会打电话给person.addChangeListener(this);。

在person类的每个setter中，您应该调用stateChanged通知侦听器Person已经更改。

每次窗口/屏幕接收到来自changeListener的事件时，它们都应该刷新适当的组件(对于ex，在JLabel中，您可以调用label.setText(person.getSurname());。

票数 0

Stack Overflow用户

发布于 2018-06-03 19:10:27

首先，感谢您的伟大建议，Guilherme Mussi。

我按以下方式更改代码。但现在这些名字不再被保存了。我不知道我做错了什么。

public class PersonFrame extends JFrame{

Person p = new Person();

JTextField tf1 = new JTextField();
JTextField tf2 = new JTextField();
JButton save = new JButton("Save");
JButton newDialog = new JButton("NewDialog");

public PersonFrame() {
    setTitle("Frame");
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    JPanel myPanel = new JPanel();
    myPanel.setLayout(new GridLayout(3,2));
    myPanel.add(new JLabel("Forename"));
    myPanel.add(new JLabel("Surname"));
    tf1.setText(Person.getForename());
    tf2.setText(Person.getSurname());
    myPanel.add(tf1);
    myPanel.add(tf2);
    save.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            p.setForename(tf1.getText());
            p.setSurname(tf2.getText());
        }
    });

    newDialog.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            SwingUtilities.updateComponentTreeUI(myPanel);
            PersonFrame personFrame = new PersonFrame();
            personFrame.pack();
            personFrame.setVisible(true);
        }
    });
    myPanel.add(save);
    myPanel.add(newDialog);
    this.getContentPane().add(myPanel);
}

public static void main(String[] args) throws InterruptedException {
    PersonFrame personFrame = new PersonFrame();
    personFrame.pack();
    personFrame.setVisible(true);
}

}

个人类别：

public class Person {

private static String forename;
private static String surname;


public void setForename(String forename) {
    ChangeListener changingForename = new ChangeListener() {
        @Override
        public void stateChanged(ChangeEvent e) {
            Person.forename = forename;
        }
    };
}

public void setSurname(String surname) {
    ChangeListener changingSurename = new ChangeListener() {
        @Override
        public void stateChanged(ChangeEvent e) {
            Person.surname = surname;
        }
    };

}

public static String getSurname() {
    if(Person.surname == null){
        return null;
    } else {
        return Person.surname;
    }
}
public static String getForename() {
    if(Person.forename == null) {
        return null;
    } else {
        return Person.forename;
    }
}

}

票数 0

Stack Overflow用户

发布于 2018-06-03 19:43:56

我修正了你的密码：

package temp;

import java.util.ArrayList;
import java.util.List;

import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class Person {
    private String surname;
    private String forename;

    private List<ChangeListener> changeListeners = new ArrayList<>();

    public void addChangeListener(ChangeListener listener) {
        changeListeners.add(listener);
    }

    public String getSurname() {
        return surname;
    }

    public void setSurname(String surname) {
        this.surname = surname;
        for (ChangeListener listener : changeListeners) {
            listener.stateChanged(new ChangeEvent(this));
        }
    }

    public String getForename() {
        return forename;
    }

    public void setForename(String forename) {
        this.forename = forename;
        for (ChangeListener listener : changeListeners) {
            listener.stateChanged(new ChangeEvent(this));
        }
    }

}

帧类：

package temp;

import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class PersonFrame extends JFrame implements ChangeListener {
    Person p = new Person();

    JTextField tf1 = new JTextField();
    JTextField tf2 = new JTextField();
    JButton save = new JButton("Save");
    JButton newDialog = new JButton("NewDialog");

    JLabel fornameLabel = new JLabel("Forename");
    JLabel surnameLabel = new JLabel("Surname");

    public PersonFrame() {
        setTitle("Frame");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        JPanel myPanel = new JPanel();
        myPanel.setLayout(new GridLayout(3,2));
        myPanel.add(fornameLabel);
        myPanel.add(surnameLabel);
        tf1.setText(p.getForename());
        tf2.setText(p.getSurname());
        myPanel.add(tf1);
        myPanel.add(tf2);

        save.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                p.setForename(tf1.getText());
                p.setSurname(tf2.getText());
            }
        });

        p.addChangeListener(this);

        newDialog.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                SwingUtilities.updateComponentTreeUI(myPanel);
                PersonFrame personFrame = new PersonFrame();
                personFrame.pack();
                personFrame.setVisible(true);
            }
        });
        myPanel.add(save);
        myPanel.add(newDialog);
        this.getContentPane().add(myPanel);
    }

    public static void main(String[] args) throws InterruptedException {
        PersonFrame personFrame = new PersonFrame();
        personFrame.pack();
        personFrame.setVisible(true);
    }

    @Override
    public void stateChanged(ChangeEvent e) {
        fornameLabel.setText(p.getForename());
        surnameLabel.setText(p.getSurname());
    }
}

我让这些值存储在标签上。我想你会知道从现在开始该如何前进。如果你还有其他问题，请提出一个新的问题。

票数 0

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/50669808

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