我下面的代码是一个工作代码，我想为我不那么短的代码道歉。我的按钮有问题，因为它们只执行一次操作。我的问题是，当我单击下一步按钮时，我有一个 validateText() 方法来检查 textarea 是否为空。我的问题来了..当面板返回到空的 textarea 时，左侧的按钮将不再起作用。但是，当您关闭程序并再次运行它时，除非您单击带有空 textarea 的下一个按钮，否则该按钮将起作用。有谁可以指出我的错误吗？
package cardlayoutalignment;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import javax.swing.border.BevelBorder;
import javax.swing.border.Border;
import javax.swing.border.EmptyBorder;
public class gridbaglayoutdemo {
JFrame Card = new JFrame();
FlowLayout flow = new FlowLayout(FlowLayout.RIGHT,2,2);
Border etch = BorderFactory.createEtchedBorder(Color.white,Color.gray);
Border margin = new EmptyBorder(10,10,10,10);
public static GridBagLayout grid = new GridBagLayout();
GridBagConstraints c = new GridBagConstraints();
final static boolean shouldFill = true;
JPanel container;
JPanel divider = new JPanel();
JPanel bodypanel = new JPanel();
final JPanel buttonpanel = new JPanel();
JPanel panel_1 = new JPanel();
JPanel panel_2 = new JPanel();
JPanel panel_3 = new JPanel();
CardLayout cl = new CardLayout();
JTextArea text_2;
JTextArea text_3;
String change = "Finish";
final JButton btnNext;
final JButton btnBack;
int currentCard = 0;
int cardflag = 0;
AbstractAction backAction;
AbstractAction nextAction;
public gridbaglayoutdemo(){
Card.setVisible(true);
Card.setSize(605,333);
Card.setTitle("Tank Delivery");
Card.setResizable(false);
final Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension dimension = Toolkit.getDefaultToolkit().getScreenSize();
int x=(int)((dimension.getWidth() - Card.getWidth())/2);
int y=(int)((dimension.getHeight() - Card.getHeight())/2);
Card.setLocation(x, y);
Card.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
bodypanel.setLayout(new BorderLayout());
divider.setLayout(new BorderLayout());
container = new JPanel(cl);
container.setLayout(cl);
cl.show(container, "1");
panel_1.setLayout(grid);
JLabel label_1 = new JLabel("Enter 1:");
label_1.setFont(new Font("Arial", Font.PLAIN, 18));
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.weighty = 0;
c.gridx = 0;
c.gridy = 0;
c.insets = new Insets(10,10,0,0);
panel_1.add(label_1, c);
JComboBox box_1 = new JComboBox();
box_1.setPreferredSize(new Dimension(200,30));
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.weighty = 0;
c.gridx = 0;
c.gridy = 1;
c.insets = new Insets(10,10,0,0);
panel_1.add(box_1,c);
JLabel label = new JLabel("");
label.setFont(new Font("Arial", Font.PLAIN, 18));
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.weighty = 1;
c.gridx = 0;
c.gridy = 2;
c.insets = new Insets(10,0,0,0);
panel_1.add(label, c);
panel_2.setLayout(grid);
JLabel label_2 = new JLabel("Enter 2:");
label_2.setFont(new Font("Arial", Font.PLAIN, 18));
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.weighty = 0;
c.gridx = 0;
c.gridy = 0;
c.insets = new Insets(10,10,0,0);
panel_2.add(label_2,c);
text_2 = new JTextArea();
text_2.setPreferredSize(new Dimension(200,30));
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.weighty = 0;
c.gridx = 0;
c.gridy = 20;
c.insets = new Insets(10,10,0,0);
panel_2.add(text_2,c);
JLabel label_22 = new JLabel("");
label_22.setFont(new Font("Arial", Font.PLAIN, 18));
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.weighty = 1;
c.gridx = 0;
c.gridy = 30;
c.insets = new Insets(10,0,0,0);
panel_2.add(label_22, c);
panel_3.setLayout(grid);
JLabel label_3 = new JLabel("Enter 3:");
label_3.setFont(new Font("Arial", Font.PLAIN, 18));
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.weighty = 0;
c.gridx = 0;
c.gridy = 0;
c.insets = new Insets(10,10,0,0);
panel_3.add(label_3,c);
text_3 = new JTextArea();
text_3.setPreferredSize(new Dimension(200,30));
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.weighty = 0;
c.gridx = 0;
c.gridy = 20;
c.insets = new Insets(10,10,0,0);
panel_3.add(text_3,c);
JLabel label_33 = new JLabel("");
label_33.setFont(new Font("Arial", Font.PLAIN, 18));
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 0.5;
c.weighty = 1;
c.gridx = 0;
c.gridy = 30;
c.insets = new Insets(10,0,0,0);
panel_3.add(label_33, c);
buttonpanel.setLayout(new FlowLayout(SwingConstants.RIGHT));
buttonpanel.setBorder(new EmptyBorder(0,10,0,0));
backAction = new AbstractAction("< Back") {
public void actionPerformed(ActionEvent e) {
currentCard--;
gridbaglayoutdemo.this.evaluateActions();
}
};
nextAction = new AbstractAction("Next >") {
public void actionPerformed(ActionEvent e) {
currentCard++;
gridbaglayoutdemo.this.evaluateActions();
}
};
buttonpanel.setLayout(new FlowLayout(SwingConstants.RIGHT));
buttonpanel.setBorder(new EmptyBorder(0,0,0,0));
btnBack = new JButton("< Back");
btnBack.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
cl.previous(container);
buttonpanel.repaint();
cardflag--;
if (cardflag==0)
{btnBack.setEnabled(false);}
if(cardflag<3)
{btnNext.setText("Next >");}
}
});
btnBack.setEnabled(false);
btnBack.setFont(new Font("Arial", Font.PLAIN, 20));
btnBack.setBorder(new BevelBorder(BevelBorder.RAISED, Color.BLACK, null, null, null));
btnBack.setPreferredSize(new Dimension(110, 40));
btnBack.setBackground(new Color(224,223,227));
buttonpanel.add(btnBack);
btnNext = new JButton("Next >");
btnNext.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
cl.next(container);
buttonpanel.repaint();
cardflag++;
if(cardflag<3)
{btnBack.setEnabled(true);}
if(cardflag==2)
{btnNext.setText(change);}
if (cardflag==3)
{cl.show(container, "3");
JOptionPane.showMessageDialog(null, "DONE");
Window dialog = SwingUtilities.windowForComponent( btnNext );
dialog.dispose();
cardflag=0;
btnNext.setText("Next >");
}
validateText();
}
});
btnNext.setFont(new Font("Arial", Font.PLAIN, 20));
btnNext.setBorder(new BevelBorder(BevelBorder.RAISED, Color.BLACK, null, null, null));
btnNext.setPreferredSize(new Dimension(110, 40));
btnNext.setBackground(new Color(224,223,227));
btnNext.setVisible(true);
buttonpanel.add(btnNext);
final JButton btnCancel = new JButton("Cancel");
btnCancel.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Window dialog = SwingUtilities.windowForComponent( btnCancel );
dialog.dispose();
}
});
btnCancel.setFont(new Font("Arial", Font.PLAIN, 20));
btnCancel.setFocusable(false);
btnCancel.setFocusTraversalKeysEnabled(false);
btnCancel.setFocusPainted(false);
btnCancel.setBorder(new BevelBorder(BevelBorder.RAISED, Color.BLACK, null, null, null));
btnCancel.setPreferredSize(new Dimension(110, 40));
btnCancel.setBackground(new Color(224,223,227));
buttonpanel.add(btnCancel);
JPanel numberpanel = new JPanel();
numberpanel.setPreferredSize(new Dimension(221,0));
numberpanel.setBorder(new EmptyBorder(10,0,0,10));
numberpanel.setBorder(BorderFactory.createEtchedBorder(Color.white,Color.gray));
numberpanel.setLayout(flow);
JButton button_7 = new JButton("7");
button_7.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
buttonaction(e);
}
});
button_7.setActionCommand("7");
button_7.setFont(new Font("Arial", Font.PLAIN, 30));
button_7.setFocusable(false);
button_7.setFocusTraversalKeysEnabled(false);
button_7.setFocusPainted(false);
button_7.setBorder(new BevelBorder(BevelBorder.RAISED, Color.BLACK, null, null, null));
button_7.setPreferredSize(new Dimension(70, 70));
button_7.setBackground(new Color(224,223,227));
numberpanel.add(button_7);
JButton button_8 = new JButton("8");
button_8.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
buttonaction(e);
}
});
button_8.setActionCommand("8");
button_8.setFont(new Font("Arial", Font.PLAIN, 30));
button_8.setFocusable(false);
button_8.setFocusTraversalKeysEnabled(false);
button_8.setFocusPainted(false);
button_8.setBorder(new BevelBorder(BevelBorder.RAISED, Color.BLACK, null, null, null));
button_8.setPreferredSize(new Dimension(70, 70));
button_8.setBackground(new Color(224,223,227));
numberpanel.add(button_8);
JButton button_9 = new JButton("9");
button_9.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
buttonaction(e);
}
});
button_9.setActionCommand("9");
button_9.setFont(new Font("Arial", Font.PLAIN, 30));
button_9.setFocusable(false);
button_9.setFocusTraversalKeysEnabled(false);
button_9.setFocusPainted(false);
button_9.setBorder(new BevelBorder(BevelBorder.RAISED, Color.BLACK, null, null, null));
button_9.setPreferredSize(new Dimension(70, 70));
button_9.setBackground(new Color(224,223,227));
numberpanel.add(button_9);
Card.add(bodypanel);
bodypanel.add(divider, BorderLayout.WEST);
divider.add(container, BorderLayout.NORTH);
container.add(panel_1, "1");
container.add(panel_2, "2");
container.add(panel_3, "3");
//container.add(panel_4, "4");
//container.add(p5.panel_5, "5");
//container.add(p6.panel_6, "6");
divider.add(buttonpanel, BorderLayout.SOUTH);
bodypanel.add(numberpanel, BorderLayout.EAST);
}
private void evaluateActions() {
((javax.swing.Action) backAction).setEnabled(currentCard > 0);
((javax.swing.Action) nextAction).setEnabled(currentCard < container.getComponentCount() - 1);
}
private void buttonaction(ActionEvent e){
try{
if(cardflag==1)
{text_2.append("" + e.getActionCommand());}
if(cardflag==2)
{text_3.append("" + e.getActionCommand());}
}catch(Exception IOe){}
}
private void validateText(){
if(cardflag==2)
{String text = text_2.getText();
if (text.isEmpty()==true)
{JOptionPane.showMessageDialog(null, "Text 2 is empty!");
cl.show(container, "2");
}
}
}
public static void main(String[] args){
//Use the event dispatch thread for Swing components
EventQueue.invokeLater(new Runnable()
{
@Override
public void run()
{
new gridbaglayoutdemo();
}
});
}
}
最佳答案
我不知道你在做什么，但我刚刚注意到 cardflag 状态的一件事。
当文本字段为空并单击下一个按钮时cardflag = 2，现在单击按钮，然后调用下面的操作监听器。
private void buttonaction(ActionEvent e) {
try {
if (cardflag == 1) {
text_2.append("" + e.getActionCommand());
}
if (cardflag == 2) {
text_3.append("" + e.getActionCommand());
^^^
//This should be text_2
}
} catch (Exception IOe) {
}
}
关于java - 如何使 jButton 操作不仅仅在一次运行中起作用？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25112400/