(完整源代码在底部)
所以现在我已经花了相当长的一段时间来研究这个问题。我有一个最终目标，但为了学习如何做到这一点，我创建了一个应用程序，它只需将数字加 1 并每秒将其显示为 jLabel1。我的问题是我无法让 Timer 工作。
我的研究向我展示了不同的方法，以及使用包 java.util.timer 和 javax.swing.timer 的 Timer 函数的示例>。迄今为止，它们都没有发挥作用。这绝不是代码错误的问题，而是某些方法似乎没有被调用。在我的大多数试验中，这通常归结为时间表方法。在我最近的尝试中，它归结为:
new Timer(delay, taskPerformer).start();
一直给我带来问题。原来的错误是
illegal start of type
invalid method declaration; return type required
cannot find symbol
symbol: class delay
location: class timer.TimerView.two
<identifier> expected
cannot find symbol
symbol: class taskPerformer
location: class timer.TimerView.two
<identifier> expected
';' expected
延迟明确定义为整数，但即使我用 1000 替换延迟后，它也会告诉我
illegal start of type
invalid method declaration; return type required
illegal start of type
所以现在我很茫然。我看了又看，我见过很多成功的故事，但它们几乎从不与 netbeans 默认 bs 一起工作。我无法导入 java.util.timer ，因为根据我的理解，javax.swing.timer 导入它本身或一些废话。
我很少寻求帮助，但在几个小时的查找过程中，我得到了与 36 小时前完全相同的源代码，但有一堆橡皮擦烧伤。所以我真的希望有人至少能指出我正确的方向。我看过 Oricals 教程等。这总是让我留在同一个地方。我尝试过操纵其他使用计时器功能的程序，甚至尝试对 netbeans 中空白桌面应用程序附带的状态栏进行逆向工程。只是似乎没有什么想要工作。或者更有可能的是，我的经验不足让我找错了地方。在我看来，这并不是一个罕见的问题，但我无法让它发挥作用。下面发布的是我的完整程序，由于其简单性，它与空白的 Netbeans 应用程序相差不远。 (它只有一个 jLabel 和我一直在研究的类)
/*
* TimerView.java
*/
package timer;
import org.jdesktop.application.Action;
import org.jdesktop.application.ResourceMap;
import org.jdesktop.application.SingleFrameApplication;
import org.jdesktop.application.FrameView;
import org.jdesktop.application.TaskMonitor;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.Timer;
import javax.swing.Icon;
import javax.swing.JDialog;
import javax.swing.JFrame;
/**
* The application's main frame.
*/
public class TimerView extends FrameView {
public TimerView(SingleFrameApplication app) {
super(app);
initComponents();
// status bar initialization - message timeout, idle icon and busy animation, etc
ResourceMap resourceMap = getResourceMap();
int messageTimeout = resourceMap.getInteger("StatusBar.messageTimeout");
messageTimer = new Timer(messageTimeout, new ActionListener() {
public void actionPerformed(ActionEvent e) {
statusMessageLabel.setText("");
}
});
messageTimer.setRepeats(false);
int busyAnimationRate = resourceMap.getInteger("StatusBar.busyAnimationRate");
for (int i = 0; i < busyIcons.length; i++) {
busyIcons[i] = resourceMap.getIcon("StatusBar.busyIcons[" + i + "]");
}
busyIconTimer = new Timer(busyAnimationRate, new ActionListener() {
public void actionPerformed(ActionEvent e) {
busyIconIndex = (busyIconIndex + 1) % busyIcons.length;
statusAnimationLabel.setIcon(busyIcons[busyIconIndex]);
}
});
idleIcon = resourceMap.getIcon("StatusBar.idleIcon");
statusAnimationLabel.setIcon(idleIcon);
progressBar.setVisible(false);
// connecting action tasks to status bar via TaskMonitor
TaskMonitor taskMonitor = new TaskMonitor(getApplication().getContext());
taskMonitor.addPropertyChangeListener(new java.beans.PropertyChangeListener() {
public void propertyChange(java.beans.PropertyChangeEvent evt) {
String propertyName = evt.getPropertyName();
if ("started".equals(propertyName)) {
if (!busyIconTimer.isRunning()) {
statusAnimationLabel.setIcon(busyIcons[0]);
busyIconIndex = 0;
busyIconTimer.start();
}
progressBar.setVisible(true);
progressBar.setIndeterminate(true);
} else if ("done".equals(propertyName)) {
busyIconTimer.stop();
statusAnimationLabel.setIcon(idleIcon);
progressBar.setVisible(false);
progressBar.setValue(0);
} else if ("message".equals(propertyName)) {
String text = (String)(evt.getNewValue());
statusMessageLabel.setText((text == null) ? "" : text);
messageTimer.restart();
} else if ("progress".equals(propertyName)) {
int value = (Integer)(evt.getNewValue());
progressBar.setVisible(true);
progressBar.setIndeterminate(false);
progressBar.setValue(value);
}
}
});
}
@Action
public void showAboutBox() {
if (aboutBox == null) {
JFrame mainFrame = TimerApp.getApplication().getMainFrame();
aboutBox = new TimerAboutBox(mainFrame);
aboutBox.setLocationRelativeTo(mainFrame);
}
TimerApp.getApplication().show(aboutBox);
}
/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
mainPanel = new javax.swing.JPanel();
jLabel1 = new javax.swing.JLabel();
menuBar = new javax.swing.JMenuBar();
javax.swing.JMenu fileMenu = new javax.swing.JMenu();
javax.swing.JMenuItem exitMenuItem = new javax.swing.JMenuItem();
javax.swing.JMenu helpMenu = new javax.swing.JMenu();
javax.swing.JMenuItem aboutMenuItem = new javax.swing.JMenuItem();
statusPanel = new javax.swing.JPanel();
javax.swing.JSeparator statusPanelSeparator = new javax.swing.JSeparator();
statusMessageLabel = new javax.swing.JLabel();
statusAnimationLabel = new javax.swing.JLabel();
progressBar = new javax.swing.JProgressBar();
mainPanel.setName("mainPanel"); // NOI18N
org.jdesktop.application.ResourceMap resourceMap = org.jdesktop.application.Application.getInstance(timer.TimerApp.class).getContext().getResourceMap(TimerView.class);
jLabel1.setText(resourceMap.getString("jLabel1.text")); // NOI18N
jLabel1.setName("jLabel1"); // NOI18N
javax.swing.GroupLayout mainPanelLayout = new javax.swing.GroupLayout(mainPanel);
mainPanel.setLayout(mainPanelLayout);
mainPanelLayout.setHorizontalGroup(
mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(mainPanelLayout.createSequentialGroup()
.addGap(178, 178, 178)
.addComponent(jLabel1)
.addContainerGap(188, Short.MAX_VALUE))
);
mainPanelLayout.setVerticalGroup(
mainPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(mainPanelLayout.createSequentialGroup()
.addGap(107, 107, 107)
.addComponent(jLabel1)
.addContainerGap(133, Short.MAX_VALUE))
);
menuBar.setName("menuBar"); // NOI18N
fileMenu.setText(resourceMap.getString("fileMenu.text")); // NOI18N
fileMenu.setName("fileMenu"); // NOI18N
javax.swing.ActionMap actionMap = org.jdesktop.application.Application.getInstance(timer.TimerApp.class).getContext().getActionMap(TimerView.class, this);
exitMenuItem.setAction(actionMap.get("quit")); // NOI18N
exitMenuItem.setName("exitMenuItem"); // NOI18N
fileMenu.add(exitMenuItem);
menuBar.add(fileMenu);
helpMenu.setText(resourceMap.getString("helpMenu.text")); // NOI18N
helpMenu.setName("helpMenu"); // NOI18N
aboutMenuItem.setAction(actionMap.get("showAboutBox")); // NOI18N
aboutMenuItem.setName("aboutMenuItem"); // NOI18N
helpMenu.add(aboutMenuItem);
menuBar.add(helpMenu);
statusPanel.setName("statusPanel"); // NOI18N
statusPanelSeparator.setName("statusPanelSeparator"); // NOI18N
statusMessageLabel.setName("statusMessageLabel"); // NOI18N
statusAnimationLabel.setHorizontalAlignment(javax.swing.SwingConstants.LEFT);
statusAnimationLabel.setName("statusAnimationLabel"); // NOI18N
progressBar.setName("progressBar"); // NOI18N
javax.swing.GroupLayout statusPanelLayout = new javax.swing.GroupLayout(statusPanel);
statusPanel.setLayout(statusPanelLayout);
statusPanelLayout.setHorizontalGroup(
statusPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(statusPanelSeparator, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE)
.addGroup(statusPanelLayout.createSequentialGroup()
.addContainerGap()
.addComponent(statusMessageLabel)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 230, Short.MAX_VALUE)
.addComponent(progressBar, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(statusAnimationLabel)
.addContainerGap())
);
statusPanelLayout.setVerticalGroup(
statusPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(statusPanelLayout.createSequentialGroup()
.addComponent(statusPanelSeparator, javax.swing.GroupLayout.PREFERRED_SIZE, 2, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addGroup(statusPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(statusMessageLabel)
.addComponent(statusAnimationLabel)
.addComponent(progressBar, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(3, 3, 3))
);
setComponent(mainPanel);
setMenuBar(menuBar);
setStatusBar(statusPanel);
}// </editor-fold>
public class two {
int delay = 1000;
ActionListener taskPerformer = new ActionListener() {
public void actionPerformed(ActionEvent evt) {
int Number = 0;
String Output;
Number++;
Output = Integer.toString(Number);
jLabel1.setText(Output);
}
};
new Timer(1000, taskPerformer).start();
}
// Variables declaration - do not modify
private javax.swing.JLabel jLabel1;
private javax.swing.JPanel mainPanel;
private javax.swing.JMenuBar menuBar;
private javax.swing.JProgressBar progressBar;
private javax.swing.JLabel statusAnimationLabel;
private javax.swing.JLabel statusMessageLabel;
private javax.swing.JPanel statusPanel;
// End of variables declaration
private final Timer messageTimer;
private final Timer busyIconTimer;
private final Icon idleIcon;
private final Icon[] busyIcons = new Icon[15];
private int busyIconIndex = 0;
private JDialog aboutBox;
}
最佳答案
1) 我建议使用javax.swing.Timer而不是 java.util.Timer，因为 javax.swing.Timer 的输出始终为 EDT
2) 从 java.util.Timer 到 GUI 的输出必须包装到 invokeLater 中，否则无法保证任何内容都应该显示/更改/重新绘制
3) 要了解更多信息，您必须阅读Concurency in Swing
4) 我建议您手动创建代码，而不是使用不受支持的 Java 桌面应用程序 并使用 GroupLayout 进行布局，
关于java - 如何获取计时器(Util 或 Swing)以允许我调用 Netbeans 桌面应用程序中的方法？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/8485151/