在两个JComboBox之间共享相同的模型 [英] Sharing same model between two JComboBoxes

问题描述

我有一个 Person [] ，有三个人（p1，p2，p3）。 Person类有两个属性 name 和 email 。

我想在一个中添加Person []的所有名称JComboBox和另一个JComboBox中的所有电子邮件。

我使用了以下代码。

 人p1 =新人（史密斯，smith @mail.com）; 
人p2 =新人（Tom，[e-mail]）; 
人p3 =新人（John，[e-mail]）; 
 
 Person [] per_arr = new Person [] {p1，p2，p3}; 
 
 JFrame frame = new JFrame（）; 
 JPanel panel = new JPanel（）; 
 JComboBox< String> combo1 = new JComboBox< String>（）; 
 JComboBox< String> combo2 = new JComboBox< String>（）; 
 
 for（Person p：per_arr）{
 combo1.addItem（p.getName（））; 
 combo2.addItem（p.getEmail（））; 
} 
 panel.add（combo1）; 
 panel.add（combo2）; 
 frame.setContentPane（panel）; 
 frame.pack（）; 
 frame.setVisible（true）; 
  

但我不想这样使用。我想使用具有相同型号的两个组合框。我尝试使用 DefaultComboBoxModel 和覆盖 getElementAt（）方法，如下所示。

 公共类MyModel扩展DefaultComboBoxModel< Object> {
 
 public MyModel（Object [] items）{
 super（items）; 
} 
 
 @Override 
 public Object getElementAt（int index）{
 if（super.getElementAt（index）instanceof Person）{
 return（Person ）super.getElementAt（索引）; 
} else {
返回null; 
} 
} 
  

}

上面的ComboBoxModel只给我Person对象。

问题是如何在一个JComboBox和所有电子邮件中添加Person []的所有名称另一个JComboBox 使用相同的ComboBoxModel 。

解决方案

使用 ComboBoxModel的一个实例和两个 JComboBox 的实例，每个实例都具有相同的模型。让每个 JComboBox 都有一个自定义

  import java.awt.Component; 
 import java.awt.EventQueue; 
 import java.awt.FlowLayout; 
 import java.util.function.Function; 
 import javax.swing.DefaultComboBoxModel; 
 import javax.swing.DefaultListCellRenderer; 
 import javax.swing.JComboBox; 
 import javax.swing.JFrame; 
 import javax.swing.JLabel; 
 import javax.swing.JList; 
 
 / ** 
 * @see http://stackoverflow.com/a/372​​22598/230513 
 * / 
公共类ComboRendererTest {
 
 private void display（）{
 JFrame f = new JFrame（Test）; 
 f.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）; 
 f.setLayout（new FlowLayout（））; 
 DefaultComboBoxModel model = new DefaultComboBoxModel（new Person [] {
 new Person（Alpher，[e-mail]），
 new Person（Bethe，bethe @ example .com），
新人（Gammow，[e-mail]）}）; 
 JComboBox< String> combo1 = new JComboBox<>（model）; 
 combo1.setRenderer（new PersonRenderer（Person :: getName））; 
 JComboBox< String> combo2 = new JComboBox<>（model）; 
 combo2.setRenderer（new PersonRenderer（Person :: getEmail））; 
 f.add（combo1）; 
 f.add（combo2）; 
 f.pack（）; 
 f.setLocationRelativeTo（null）; 
 f.setVisible（true）; 
} 
 
私有静态类PersonRenderer扩展DefaultListCellRenderer {
 
函数< Person，String> personAttribute; 
 
 public PersonRenderer（Function< Person，String> personAttribute）{
 this.personAttribute = personAttribute; 
} 
 
 @Override 
 public Component getListCellRendererComponent（JList<？> list，Object 
 value，int index，boolean isSelected，boolean cellHasFocus）{
 JLabel l =（JLabel）super.getListCellRendererComponent（
 list，value，index，isSelected，cellHasFocus）; 
人p =（人）价值; 
 l.setText（personAttribute.apply（p））; 
返回l; 
} 
} 
 
私有静态类人员{
 
私人最终字符串名称; 
 private final String email; 
 
 public Person（String name，String email）{
 this.name = name; 
 this.email = email; 
} 
 
 public String getName（）{
 return name; 
} 
 
 public String getEmail（）{
 return email; 
} 
} 
 
 public static void main（String [] args）{
 EventQueue.invokeLater（new ComboRendererTest（）:: display）; 
} 
} 
  

I have a Person [ ] with three Persons (p1,p2,p3). Person class has two attributes name and email.

I want to add all names of Person[] in one JComboBox and all emails in another JComboBox.

I used the following code.

    Person p1 = new Person("Smith", "[e-mail]");
    Person p2 = new Person("Tom", "[e-mail]");
    Person p3 = new Person("John","[e-mail]");

    Person[] per_arr = new Person[] { p1, p2, p3};

    JFrame frame = new JFrame();
    JPanel panel = new JPanel();
    JComboBox<String> combo1 = new JComboBox<String>();
    JComboBox<String> combo2 = new JComboBox<String>();

    for (Person p : per_arr) {
        combo1.addItem(p.getName());
        combo2.addItem(p.getEmail());
    }
    panel.add(combo1);
    panel.add(combo2);
    frame.setContentPane(panel);
    frame.pack();
    frame.setVisible(true);

But I don't want to used like this. I'd like to use the two combo boxes with the same model. I tried with DefaultComboBoxModel and Override getElementAt() method like the following.

public class MyModel extends DefaultComboBoxModel<Object> {

public MyModel(Object[] items) {
    super(items);
}

@Override
public Object getElementAt(int index) {
    if (super.getElementAt(index) instanceof Person) {
        return (Person)super.getElementAt(index);
    } else {
        return null;
    }
}

}

The above ComboBoxModel give me only the Person objects.

The Question is how can I add all names of Person[] in one JComboBox and all emails in another JComboBox using same ComboBoxModel .

解决方案

Use one instance of ComboBoxModel and two instances of JComboBox, each having the same model. Let each JComboBox have a custom renderer that displays the desired Person attribute for that JComboBox.

In the example below, each combo gets its own instance of a single renderer that implements the strategy pattern, passing a Function<Person, String> that selects the correct attribute when the renderer is called:

DefaultComboBoxModel model = new DefaultComboBoxModel(…);
JComboBox<String> combo1 = new JComboBox<>(model);
combo1.setRenderer(new PersonRenderer(Person::getName));
JComboBox<String> combo2 = new JComboBox<>(model);
combo2.setRenderer(new PersonRenderer(Person::getEmail));

import java.awt.Component;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.util.function.Function;
import javax.swing.DefaultComboBoxModel;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;

/**
 * @see http://stackoverflow.com/a/37222598/230513
 */
public class ComboRendererTest {

    private void display() {
        JFrame f = new JFrame("Test");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setLayout(new FlowLayout());
        DefaultComboBoxModel model = new DefaultComboBoxModel(new Person[]{
            new Person("Alpher", "[e-mail]"),
            new Person("Bethe", "[e-mail]"),
            new Person("Gammow", "[e-mail]")});
        JComboBox<String> combo1 = new JComboBox<>(model);
        combo1.setRenderer(new PersonRenderer(Person::getName));
        JComboBox<String> combo2 = new JComboBox<>(model);
        combo2.setRenderer(new PersonRenderer(Person::getEmail));
        f.add(combo1);
        f.add(combo2);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    private static class PersonRenderer extends DefaultListCellRenderer {

        Function<Person, String> personAttribute;

        public PersonRenderer(Function<Person, String> personAttribute) {
            this.personAttribute = personAttribute;
        }

        @Override
        public Component getListCellRendererComponent(JList<?> list, Object
            value, int index, boolean isSelected, boolean cellHasFocus) {
            JLabel l = (JLabel) super.getListCellRendererComponent(
                list, value, index, isSelected, cellHasFocus);
            Person p = (Person) value;
            l.setText(personAttribute.apply(p));
            return l;
        }
    }

    private static class Person {

        private final String name;
        private final String email;

        public Person(String name, String email) {
            this.name = name;
            this.email = email;
        }

        public String getName() {
            return name;
        }

        public String getEmail() {
            return email;
        }
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new ComboRendererTest()::display);
    }
}

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