我认为在“真实的Swing生活”中最难理解的设计模式之一是MVC模式。我已经阅读了该站点上许多讨论该模式的帖子，但我仍然不清楚如何在我的Java Swing应用程序中利用该模式。
假设我有一个包含表格、几个文本字段和一些按钮的JFrame。我可能会使用TableModel将JTable与底层数据模型“桥接”起来。然而，所有负责清除字段、验证字段、锁定字段以及按钮操作的函数通常都会直接放在JFrame中。但是，这难道不会混淆模式的控制器和视图吗？
据我所见，当我查看JTable（和模型）时，我成功地实现了MVC模式，但是当我将整个JFrame作为一个整体来看时，情况就变得混乱了。
我很想听听其他人在使用MVC模式显示表格、几个字段和一些按钮时是如何处理的。
您是用户，与视图交互。 视图是您查看模型的窗口。当您对视图执行某些操作（例如单击“播放”按钮）时，视图会将此操作告诉控制器。控制器负责处理该操作。
控制器请求模型更改其状态。 控制器接受您的操作并解释它们。如果您单击一个按钮，控制器的工作就是弄清楚这意味着什么，以及基于该操作应如何操作模型。
控制器也可以要求视图更改。 当控制器从视图接收到一个操作时，可能需要告诉视图进行相应的更改。例如，控制器可以在界面中启用或禁用某些按钮或菜单项。
模型在其状态发生更改时通知视图。 当模型发生更改时，基于您采取的某些操作（例如单击按钮）或某些其他内部更改（例如播放列表中的下一首歌曲已开始），模型会通知视图其状态已更改。
视图请求模型的状态。 视图直接从模型获取其显示的状态。例如，当模型通知视图已开始播放新歌曲时，视图会请求模型中的歌曲名称并显示它。视图还可能在控制器请求对视图进行某些更改后向模型请求状态。
=D - aaiezza我不太喜欢模型更改数据后需要通知视图的想法，我会将这个功能委托给控制器。这样，如果您更改了应用程序的逻辑，就不需要干预视图的代码。视图的任务仅仅是为应用程序组件和布局服务而已。在swing中进行布局已经是一个冗长的任务了，为什么要让它干扰应用程序的逻辑呢？
我的MVC思想（我目前正在使用，效果不错）是：
视图：
就像我说的，创建视图已经够冗长的了，所以请自己编写实现吧 :)
interface View{
JTextField getTxtFirstName();
JTextField getTxtLastName();
JTextField getTxtAddress();
}
为了测试的目的，将这三者连接起来是理想的。我仅提供了我的 Model 和 Controller 实现。
Model：
public class MyImplementationOfModel implements Model{
...
private SwingPropertyChangeSupport propChangeFirer;
private String address;
private String firstName;
private String lastName;
public MyImplementationOfModel() {
propChangeFirer = new SwingPropertyChangeSupport(this);
}
public void addListener(PropertyChangeListener prop) {
propChangeFirer.addPropertyChangeListener(prop);
}
public void setAddress(String address){
String oldVal = this.address;
this.address = address;
//after executing this, the controller will be notified that the new address has been set. Its then the controller's
//task to decide what to do when the address in the model has changed. Ideally, the controller will update the view about this
propChangeFirer.firePropertyChange("address", oldVal, address);
}
...
//some other setters for other properties & code for database interaction
...
}
控制器：
public class MyImplementationOfController implements PropertyChangeListener, Controller{
private View view;
private Model model;
public MyImplementationOfController(View view, Model model){
this.view = view;
this.model = model;
//register the controller as the listener of the model
this.model.addListener(this);
setUpViewEvents();
}
//code for setting the actions to be performed when the user interacts to the view.
private void setUpViewEvents(){
view.getBtnClear().setAction(new AbstractAction("Clear") {
@Override
public void actionPerformed(ActionEvent arg0) {
model.setFirstName("");
model.setLastName("");
model.setAddress("");
}
});
view.getBtnSave().setAction(new AbstractAction("Save") {
@Override
public void actionPerformed(ActionEvent arg0) {
...
//validate etc.
...
model.setFirstName(view.getTxtFName().getText());
model.setLastName(view.getTxtLName().getText());
model.setAddress(view.getTxtAddress().getText());
model.save();
}
});
}
public void propertyChange(PropertyChangeEvent evt){
String propName = evt.getPropertyName();
Object newVal = evt.getNewValue();
if("address".equalsIgnoreCase(propName)){
view.getTxtAddress().setText((String)newVal);
}
//else if property (name) that fired the change event is first name property
//else if property (name) that fired the change event is last name property
}
}
主要部分，其中MVC被设置：
public class Main{
public static void main(String[] args){
View view = new YourImplementationOfView();
Model model = new MyImplementationOfModel();
...
//create jframe
//frame.add(view.getUI());
...
//make sure the view and model is fully initialized before letting the controller control them.
Controller controller = new MyImplementationOfController(view, model);
...
//frame.setVisible(true);
...
}
}
例子
详细解释、示例应用和源代码：https://www.link-intersystems.com/blog/2013/07/20/the-mvc-pattern-implemented-with-java-swing/。
不到260行的MVC基础知识：
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.DefaultListModel;
import javax.swing.DefaultListSelectionModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.ListSelectionModel;
import javax.swing.WindowConstants;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.PlainDocument;
public class Main {
public static void main(String[] args) {
JFrame mainFrame = new JFrame("MVC example");
mainFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
mainFrame.setSize(640, 300);
mainFrame.setLocationRelativeTo(null);
PersonService personService = new PersonServiceMock();
DefaultListModel searchResultListModel = new DefaultListModel();
DefaultListSelectionModel searchResultSelectionModel = new DefaultListSelectionModel();
searchResultSelectionModel
.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
Document searchInput = new PlainDocument();
PersonDetailsAction personDetailsAction = new PersonDetailsAction(
searchResultSelectionModel, searchResultListModel);
personDetailsAction.putValue(Action.NAME, "Person Details");
Action searchPersonAction = new SearchPersonAction(searchInput,
searchResultListModel, personService);
searchPersonAction.putValue(Action.NAME, "Search");
Container contentPane = mainFrame.getContentPane();
JPanel searchInputPanel = new JPanel();
searchInputPanel.setLayout(new BorderLayout());
JTextField searchField = new JTextField(searchInput, null, 0);
searchInputPanel.add(searchField, BorderLayout.CENTER);
searchField.addActionListener(searchPersonAction);
JButton searchButton = new JButton(searchPersonAction);
searchInputPanel.add(searchButton, BorderLayout.EAST);
JList searchResultList = new JList();
searchResultList.setModel(searchResultListModel);
searchResultList.setSelectionModel(searchResultSelectionModel);
JPanel searchResultPanel = new JPanel();
searchResultPanel.setLayout(new BorderLayout());
JScrollPane scrollableSearchResult = new JScrollPane(searchResultList);
searchResultPanel.add(scrollableSearchResult, BorderLayout.CENTER);
JPanel selectionOptionsPanel = new JPanel();
JButton showPersonDetailsButton = new JButton(personDetailsAction);
selectionOptionsPanel.add(showPersonDetailsButton);
contentPane.add(searchInputPanel, BorderLayout.NORTH);
contentPane.add(searchResultPanel, BorderLayout.CENTER);
contentPane.add(selectionOptionsPanel, BorderLayout.SOUTH);
mainFrame.setVisible(true);
}
}
class PersonDetailsAction extends AbstractAction {
private static final long serialVersionUID = -8816163868526676625L;
private ListSelectionModel personSelectionModel;
private DefaultListModel personListModel;
public PersonDetailsAction(ListSelectionModel personSelectionModel,
DefaultListModel personListModel) {
boolean unsupportedSelectionMode = personSelectionModel
.getSelectionMode() != ListSelectionModel.SINGLE_SELECTION;
if (unsupportedSelectionMode) {
throw new IllegalArgumentException(
"PersonDetailAction can only handle single list selections. "
+ "Please set the list selection mode to ListSelectionModel.SINGLE_SELECTION");
}
this.personSelectionModel = personSelectionModel;
this.personListModel = personListModel;
personSelectionModel
.addListSelectionListener(new ListSelectionListener() {
public void valueChanged(ListSelectionEvent e) {
ListSelectionModel listSelectionModel = (ListSelectionModel) e
.getSource();
updateEnablement(listSelectionModel);
}
});
updateEnablement(personSelectionModel);
}
public void actionPerformed(ActionEvent e) {
int selectionIndex = personSelectionModel.getMinSelectionIndex();
PersonElementModel personElementModel = (PersonElementModel) personListModel
.get(selectionIndex);
Person person = personElementModel.getPerson();
String personDetials = createPersonDetails(person);
JOptionPane.showMessageDialog(null, personDetials);
}
private String createPersonDetails(Person person) {
return person.getId() + ": " + person.getFirstName() + " "
+ person.getLastName();
}
private void updateEnablement(ListSelectionModel listSelectionModel) {
boolean emptySelection = listSelectionModel.isSelectionEmpty();
setEnabled(!emptySelection);
}
}
class SearchPersonAction extends AbstractAction {
private static final long serialVersionUID = 4083406832930707444L;
private Document searchInput;
private DefaultListModel searchResult;
private PersonService personService;
public SearchPersonAction(Document searchInput,
DefaultListModel searchResult, PersonService personService) {
this.searchInput = searchInput;
this.searchResult = searchResult;
this.personService = personService;
}
public void actionPerformed(ActionEvent e) {
String searchString = getSearchString();
List<Person> matchedPersons = personService.searchPersons(searchString);
searchResult.clear();
for (Person person : matchedPersons) {
Object elementModel = new PersonElementModel(person);
searchResult.addElement(elementModel);
}
}
private String getSearchString() {
try {
return searchInput.getText(0, searchInput.getLength());
} catch (BadLocationException e) {
return null;
}
}
}
class PersonElementModel {
private Person person;
public PersonElementModel(Person person) {
this.person = person;
}
public Person getPerson() {
return person;
}
@Override
public String toString() {
return person.getFirstName() + ", " + person.getLastName();
}
}
interface PersonService {
List<Person> searchPersons(String searchString);
}
class Person {
private int id;
private String firstName;
private String lastName;
public Person(int id, String firstName, String lastName) {
this.id = id;
this.firstName = firstName;
this.lastName = lastName;
}
public int getId() {
return id;
}
public String getFirstName() {
return firstName;
}
public String getLastName() {
return lastName;
}
}
class PersonServiceMock implements PersonService {
private List<Person> personDB;
public PersonServiceMock() {
personDB = new ArrayList<Person>();
personDB.add(new Person(1, "Graham", "Parrish"));
personDB.add(new Person(2, "Daniel", "Hendrix"));
personDB.add(new Person(3, "Rachel", "Holman"));
personDB.add(new Person(4, "Sarah", "Todd"));
personDB.add(new Person(5, "Talon", "Wolf"));
personDB.add(new Person(6, "Josephine", "Dunn"));
personDB.add(new Person(7, "Benjamin", "Hebert"));
personDB.add(new Person(8, "Lacota", "Browning "));
personDB.add(new Person(9, "Sydney", "Ayers"));
personDB.add(new Person(10, "Dustin", "Stephens"));
personDB.add(new Person(11, "Cara", "Moss"));
personDB.add(new Person(12, "Teegan", "Dillard"));
personDB.add(new Person(13, "Dai", "Yates"));
personDB.add(new Person(14, "Nora", "Garza"));
}
public List<Person> searchPersons(String searchString) {
List<Person> matches = new ArrayList<Person>();
if (searchString == null) {
return matches;
}
for (Person person : personDB) {
if (person.getFirstName().contains(searchString)
|| person.getLastName().contains(searchString)) {
matches.add(person);
}
}
return matches;
}
}
JTable视图（表格模型实际上是视图的一部分 - 它只会从“共享模型”转换为JTable）。updateCustomer(customer, newValue)，而不是updateCustomer(row, column, newValue)。TableModel（尽管如果它不仅被表格使用，我建议提供一个友好的API，不要泄漏表格抽象）。CustomerUpdateListener，OrderItemListener，OrderCancellationListener）拥有复杂的接口，并且专门为不同视图的协调器（或中介者）。我找到了一些有关实现MVC模式的有趣文章，这可能会解决你的问题。