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[英]How to get textfield that updates from listener in Java Swing for Hangman game?
[英]How to manage view updates from controllers in a Java Swing app
我發現用Swing編寫好的OO代碼非常難。 我的問題基本上是我有一個有動作監聽器的視圖(JPanel)。 動作偵聽器確定單擊了哪個按鈕並調用適當的控制器方法。 問題是此控制器方法需要更新另一個視圖。 所以我遇到的問題是我將視圖傳遞給控制器。 這是一個例子。
public class MyView extends JPanel implements ActionListener {
private final MyController controller = new MyController();
@Override public void actionPerformed(ActionEvent e) {
this.controller.updateOtherView();
}
}
這基本上就是我想要的,但這就是最終發生的事情。
public class MyView extends JPanel implements ActionListener {
private MyController controller = new MyController();
private OtherView otherView;
public MyView(MyOtherView otherView) {
this.otherView = otherView;
}
@Override public void actionPerformed(ActionEvent e) {
this.controller.updateOtherView(otherView);
}
}
您可以看到,隨着需要更新的視圖數量的增加以及看起來像這樣的類數量的增加,視圖本質上是全局變量,代碼變得復雜且不清楚。 我遇到的另一個問題是這個其他視圖通常沒有直接傳遞到MyView,但它必須通過MyView的父級才能進入MyView,這真的只是讓我煩惱。
對於一個真實的例子,假設我有一個菜單和這個MyView。 MyView有一個播放按鈕,可播放一段時間的音樂,並禁用(灰顯)播放按鈕,直到音樂結束。 如果我有一個名為play的菜單選項,現在我需要訪問其他視圖播放按鈕,這樣我就可以將它變灰了。 如果沒有這種煩人的意見傳遞,我該怎么做呢? 雖然可能有針對此問題的特定解決方案,但我正在尋找能夠解決一般情況下此視圖訪問問題的方法。
我根本不確定如何解決這個問題。 我現在正在使用MVC模式術語而不使用MVC模式,這可能是也可能不是必需的。 任何幫助表示贊賞。
一種解決方案:只需讓控制器更新模型即可。 然后附加到模型的偵聽器將更新視圖。 您還可以讓JMenuItems和相應的JButton共享相同的Action,因此當您禁用Action時,它將禁用使用該Action的所有按鈕/菜單/等。
例如,主類:
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class MvcExample {
private static void createAndShowGui() {
MyView view = new MyView();
MyMenuBar menuBar = new MyMenuBar();
MyModel model = new MyModel();
MyControl control = new MyControl(model);
control.addProgressMonitor(view);
control.addView(view);
control.addView(menuBar);
model.setState(MyState.STOP);
JFrame frame = new JFrame("MVC Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(view.getMainPanel());
frame.setJMenuBar(menuBar.getMenuBar());
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
private static final byte[] DATA_ARRAY = { 0x43, 0x6f, 0x70, 0x79, 0x72,
0x69, 0x67, 0x68, 0x74, 0x20, 0x46, 0x75, 0x62, 0x61, 0x72, 0x61,
0x62, 0x6c, 0x65, 0x2c, 0x20, 0x30, 0x36, 0x2f, 0x31, 0x36, 0x2f,
0x32, 0x30, 0x31, 0x32, 0x2e, 0x20, 0x46, 0x75, 0x62, 0x61, 0x72,
0x61, 0x62, 0x6c, 0x65, 0x20, 0x52, 0x75, 0x6c, 0x65, 0x73, 0x21 };
}
控制:
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.ArrayList;
import java.util.List;
import javax.swing.AbstractAction;
@SuppressWarnings("serial")
public class MyControl {
private MyModel model;
private PlayAction playAction = new PlayAction();
private PauseAction pauseAction = new PauseAction();
private StopAction stopAction = new StopAction();
private List<MyProgressMonitor> progMonitorList = new ArrayList<MyProgressMonitor>();
public MyControl(MyModel model) {
this.model = model;
model.addPropertyChangeListener(new MyPropChangeListener());
}
public void addProgressMonitor(MyProgressMonitor progMonitor) {
progMonitorList.add(progMonitor);
}
public void addView(MySetActions setActions) {
setActions.setPlayAction(playAction);
setActions.setPauseAction(pauseAction);
setActions.setStopAction(stopAction);
}
private class MyPropChangeListener implements PropertyChangeListener {
@Override
public void propertyChange(PropertyChangeEvent pcEvt) {
if (MyState.class.getName().equals(pcEvt.getPropertyName())) {
MyState state = (MyState) pcEvt.getNewValue();
if (state == MyState.PLAY) {
playAction.setEnabled(false);
pauseAction.setEnabled(true);
stopAction.setEnabled(true);
} else if (state == MyState.PAUSE) {
playAction.setEnabled(true);
pauseAction.setEnabled(false);
stopAction.setEnabled(true);
} else if (state == MyState.STOP) {
playAction.setEnabled(true);
pauseAction.setEnabled(false);
stopAction.setEnabled(false);
}
}
if (MyModel.PROGRESS.equals(pcEvt.getPropertyName())) {
for (MyProgressMonitor progMonitor : progMonitorList) {
int progress = (Integer) pcEvt.getNewValue();
progMonitor.setProgress(progress);
}
}
}
}
private class PlayAction extends AbstractAction {
public PlayAction() {
super("Play");
putValue(MNEMONIC_KEY, KeyEvent.VK_P);
}
@Override
public void actionPerformed(ActionEvent e) {
model.play();
}
}
private class StopAction extends AbstractAction {
public StopAction() {
super("Stop");
putValue(MNEMONIC_KEY, KeyEvent.VK_S);
}
@Override
public void actionPerformed(ActionEvent e) {
model.stop();
}
}
private class PauseAction extends AbstractAction {
public PauseAction() {
super("Pause");
putValue(MNEMONIC_KEY, KeyEvent.VK_A);
}
@Override
public void actionPerformed(ActionEvent e) {
model.pause();
}
}
}
國家枚舉:
public enum MyState {
PLAY, STOP, PAUSE
}
其中一個視圖界面:
import javax.swing.Action;
public interface MySetActions {
void setPlayAction(Action playAction);
void setPauseAction(Action pauseAction);
void setStopAction(Action stopAction);
}
另一個視圖界面:
public interface MyProgressMonitor {
void setProgress(int progress);
}
主GUI視圖:
import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.Action;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
public class MyView implements MySetActions, MyProgressMonitor {
private JButton playButton = new JButton();
private JButton stopButton = new JButton();
private JButton pauseButton = new JButton();
private JPanel mainPanel = new JPanel();
private JProgressBar progressBar = new JProgressBar();
public MyView() {
progressBar.setBorderPainted(true);
JPanel btnPanel = new JPanel(new GridLayout(1, 0, 5, 0));
btnPanel.add(playButton);
btnPanel.add(pauseButton);
btnPanel.add(stopButton);
mainPanel.setLayout(new BorderLayout(0, 5));
mainPanel.setBorder(BorderFactory.createEmptyBorder(5, 15, 5, 15));
mainPanel.add(btnPanel, BorderLayout.CENTER);
mainPanel.add(progressBar, BorderLayout.PAGE_END);
}
@Override
public void setPlayAction(Action playAction) {
playButton.setAction(playAction);
}
@Override
public void setStopAction(Action stopAction) {
stopButton.setAction(stopAction);
}
@Override
public void setPauseAction(Action pauseAction) {
pauseButton.setAction(pauseAction);
}
@Override
public void setProgress(int progress) {
progressBar.setValue(progress);
}
public JComponent getMainPanel() {
return mainPanel;
}
}
View的菜單欄部分:
import java.awt.event.KeyEvent;
import javax.swing.Action;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
public class MyMenuBar implements MySetActions {
private JMenuItem playMenItem = new JMenuItem();
private JMenuItem pauseMenuItem = new JMenuItem();
private JMenuItem stopMenItem = new JMenuItem();
private JMenuBar menuBar = new JMenuBar();
public MyMenuBar() {
JMenu menu = new JMenu("Main Menu");
menu.setMnemonic(KeyEvent.VK_M);
menu.add(playMenItem);
menu.add(pauseMenuItem);
menu.add(stopMenItem);
menuBar.add(menu);
}
public JMenuBar getMenuBar() {
return menuBar;
}
@Override
public void setPlayAction(Action playAction) {
playMenItem.setAction(playAction);
}
@Override
public void setStopAction(Action stopAction) {
stopMenItem.setAction(stopAction);
}
@Override
public void setPauseAction(Action pauseAction) {
pauseMenuItem.setAction(pauseAction);
}
}
最后,模型:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeListener;
import javax.swing.Timer;
import javax.swing.event.SwingPropertyChangeSupport;
public class MyModel {
public final static String PROGRESS = "progress";
protected static final int MAX_PROGRESS = 100;
private MyState state = null;
private SwingPropertyChangeSupport pcSupport = new SwingPropertyChangeSupport(
this);
private Timer timer;
private int progress = 0;
public MyState getState() {
return state;
}
public void setState(MyState state) {
MyState oldValue = this.state;
MyState newValue = state;
this.state = newValue;
pcSupport.firePropertyChange(MyState.class.getName(), oldValue, newValue);
}
public int getProgress() {
return progress;
}
public void setProgress(int progress) {
Integer oldValue = this.progress;
Integer newValue = progress;
this.progress = newValue;
pcSupport.firePropertyChange(PROGRESS, oldValue, newValue);
}
public void play() {
MyState oldState = getState();
setState(MyState.PLAY);
if (oldState == MyState.PAUSE) {
if (timer != null) {
timer.start();
return;
}
}
int timerDelay = 50;
// simulate playing ....
timer = new Timer(timerDelay, new ActionListener() {
int timerProgress = 0;
@Override
public void actionPerformed(ActionEvent actEvt) {
timerProgress++;
setProgress(timerProgress);
if (timerProgress >= MAX_PROGRESS) {
setProgress(0);
MyModel.this.stop();
}
}
});
timer.start();
}
public void pause() {
setState(MyState.PAUSE);
if (timer != null && timer.isRunning()) {
timer.stop();
}
}
public void stop() {
setState(MyState.STOP);
setProgress(0);
if (timer != null && timer.isRunning()) {
timer.stop();
}
timer = null;
}
public void addPropertyChangeListener(PropertyChangeListener listener) {
pcSupport.addPropertyChangeListener(listener);
}
public void removePropertyChangeListener(PropertyChangeListener listener) {
pcSupport.removePropertyChangeListener(listener);
}
}
請問一下這是否有點混亂。
在這種情況下,我傾向於使用單身人士。 當然,這取決於您的觀點的獨特性。 我通常為我的“窗戶”(JFrames)擁有單身人士,所以我可以通過使用getter從那些導航到我需要的任何孩子。 然而,在非常復雜的情況下,這可能不是最好的主意。
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