我只是想知道一些关于 Swing 的事情 1)如何在swing中使用MVC模型? 2) 假设我有一个主窗口,我需要将菜单作为单独的类,将所有组件作为单独的类,这将是集成它的最佳方法
最佳答案
好的,这被称为过度杀伤力的回答,对此深表歉意,但这是我快速创建的一个示例,它尝试使用简单的 MVC 模式来做一件微不足道的事情:按下一个按钮并更改文本中的文本JTextField。这是大材小用,因为您只需几行代码就可以做同样的事情,但它确实在单独的文件中说明了一些 MVC 以及模型如何控制状态。如果有任何混淆,请提出问题!
将所有内容放在一起并开始工作的主类:
import javax.swing.*;
public class SwingMvcTest {
private static void createAndShowUI() {
// create the model/view/control and connect them together
MvcModel model = new MvcModel();
MvcView view = new MvcView(model);
MvcControl control = new MvcControl(model);
view.setGuiControl(control);
// EDIT: added menu capability
McvMenu menu = new McvMenu(control);
// create the GUI to display the view
JFrame frame = new JFrame("MVC");
frame.getContentPane().add(view.getMainPanel()); // add view here
frame.setJMenuBar(menu.getMenuBar()); // edit: added menu capability
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
// call Swing code in a thread-safe manner per the tutorials
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}
View 类:
import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import javax.swing.*;
public class MvcView {
private MvcControl control;
private JTextField stateField = new JTextField(10);
private JPanel mainPanel = new JPanel(); // holds the main GUI and its components
public MvcView(MvcModel model) {
// add a property change listener to the model to listen and
// respond to changes in the model's state
model.addPropertyChangeListener(new PropertyChangeListener() {
public void propertyChange(PropertyChangeEvent evt) {
// if the state change is the one we're interested in...
if (evt.getPropertyName().equals(MvcModel.STATE_PROP_NAME)) {
stateField.setText(evt.getNewValue().toString()); // show it in the GUI
}
}
});
JButton startButton = new JButton("Start");
startButton.addActionListener(new ActionListener() {
// all the buttons do is call methods of the control
public void actionPerformed(ActionEvent e) {
if (control != null) {
control.startButtonActionPerformed(e); // e.g., here
}
}
});
JButton endButton = new JButton("End");
endButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (control != null) {
control.endButtonActionPerformed(e); // e.g., and here
}
}
});
// make our GUI pretty
int gap = 10;
JPanel buttonPanel = new JPanel(new GridLayout(1, 0, gap, 0));
buttonPanel.add(startButton);
buttonPanel.add(endButton);
JPanel statePanel = new JPanel(new FlowLayout(FlowLayout.CENTER, 0, 0));
statePanel.add(new JLabel("State:"));
statePanel.add(Box.createHorizontalStrut(gap));
statePanel.add(stateField);
mainPanel.setBorder(BorderFactory.createEmptyBorder(gap, gap, gap, gap));
mainPanel.setLayout(new BorderLayout(gap, gap));
mainPanel.add(buttonPanel, BorderLayout.CENTER);
mainPanel.add(statePanel, BorderLayout.PAGE_END);
}
// set the control for this view
public void setGuiControl(MvcControl control) {
this.control = control;
}
// get the main gui and its components for display
public JComponent getMainPanel() {
return mainPanel;
}
}
控件:
import java.awt.event.ActionEvent;
public class MvcControl {
private MvcModel model;
public MvcControl(MvcModel model) {
this.model = model;
}
// all this simplistic control does is change the state of the model, that's it
public void startButtonActionPerformed(ActionEvent ae) {
model.setState(State.START);
}
public void endButtonActionPerformed(ActionEvent ae) {
model.setState(State.END);
}
}
该模型使用 PropertyChangeSupport 对象来允许其他对象(在这种情况下为 View)监听状态变化。因此,模型实际上是我们的“可观察对象”,而 View 是“观察者”
import java.beans.*;
public class MvcModel {
public static final String STATE_PROP_NAME = "State";
private PropertyChangeSupport pcSupport = new PropertyChangeSupport(this);
private State state = State.NO_STATE;
public void setState(State state) {
State oldState = this.state;
this.state = state;
// notify all listeners that the state property has changed
pcSupport.firePropertyChange(STATE_PROP_NAME, oldState, state);
}
public State getState() {
return state;
}
public String getStateText() {
return state.getText();
}
// allow addition of listeners or observers
public void addPropertyChangeListener(PropertyChangeListener listener) {
pcSupport.addPropertyChangeListener(listener);
}
}
一个简单的枚举,State,封装状态的概念:
public enum State {
NO_STATE("No State"), START("Start"), END("End");
private String text;
private State(String text) {
this.text = text;
}
@Override
public String toString() {
return text;
}
public String getText() {
return text;
}
}
编辑:我看到你也提到了菜单,所以我通过添加此类和 SwingMcvTest 类中的几行来添加菜单支持。请注意,由于代码分离,对 GUI 进行此更改是微不足道的,因为所有菜单需要做的就是调用控制方法。它不需要对模型或 View 一无所知:
import java.awt.event.ActionEvent;
import javax.swing.*;
public class McvMenu {
private JMenuBar menuBar = new JMenuBar();
private MvcControl control;
@SuppressWarnings("serial")
public McvMenu(MvcControl cntrl) {
this.control = cntrl;
JMenu menu = new JMenu("Change State");
menu.add(new JMenuItem(new AbstractAction("Start") {
public void actionPerformed(ActionEvent ae) {
if (control != null) {
control.startButtonActionPerformed(ae);
}
}
}));
menu.add(new JMenuItem(new AbstractAction("End") {
public void actionPerformed(ActionEvent ae) {
if (control != null) {
control.endButtonActionPerformed(ae);
}
}
}));
menuBar.add(menu);
}
public JMenuBar getMenuBar() {
return menuBar;
}
}
上帝啊,做一些微不足道的事情需要很多代码!我提名我自己和我的代码参加本周的 stackoverflow Rube Goldberg 奖。
关于java - 如何在多个类中使用 swing,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/6087436/