Java Void对于变量main无效?
如何修复错误,Void对于main变量无效?我试着在网上查找,但什么也找不到。另外,我是新来的,所以请对我放轻松。我边走边学Java Void对于变量main无效?,java,Java,如何修复错误,Void对于main变量无效?我试着在网上查找,但什么也找不到。另外,我是新来的,所以请对我放轻松。我边走边学 import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import javax.swing.ImageIcon; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; i
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class Text extends JFrame
{
JPanel jp = new JPanel();
JLabel jl = new JLabel();
JTextField jt = new JTextField("Month",30);
JTextField jt2 = new JTextField("Date",30);
JButton jb = new JButton("Enter");
public Text()
{
public static void main (String[] args); {
setTitle("Tutorial");
setVisible(true);
setSize(400, 200);
setDefaultCloseOperation(EXIT_ON_CLOSE);
jp.add(jt);
jp.add(jt2);
jt.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
String input = jt.getText();
jl.setText(input);
}
});
jp.add(jb);
jb.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
String input = jt.getText();
String input2 = jt2.getText();
jl.setText(input);
jl.setText(input2);
int day = Integer.parseInt(input2);
if ((input.equals("Test")) && (input2.equals(day >= 26)))//||(input2.equals("27")))))
JOptionPane.showMessageDialog(null, "" , "" ,JOptionPane.PLAIN_MESSAGE,aries);
}
});
add(jp);
}
}
}
Java不允许在其他方法中定义方法。将
main
方法移出Text
构造函数,并删除提前终止语句的分号
此外,您还有许多属于JFrame
的方法(例如setTitle
和setVisible
)-这些方法需要移动到实例代码块中,以使其可访问
public class Text extends JFrame {
JPanel jp = new JPanel();
JLabel jl = ...
public Text() {
setTitle("Tutorial");
setVisible(true);
...
add(jp);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
new Text().setVisible(true);
}
});
}
}
您已将
main
方法放置在类文本的构造函数中。它属于构造函数外部,与构造函数处于同一级别。将其移到构造函数之外
public class Text extends JFrame
{
JPanel jp = new JPanel();
JLabel jl = new JLabel();
JTextField jt = new JTextField("Month",30);
JTextField jt2 = new JTextField("Date",30);
JButton jb = new JButton("Enter");
public static void main (String[] args); {
setTitle("Tutorial");
setVisible(true);
setSize(400, 200);
setDefaultCloseOperation(EXIT_ON_CLOSE);
...
}
public Text()
{
...
}
...
}
删除代码>在main
方法声明之后:
public static void main (String[] args);
^-------- Delete this
并将main
方法移出构造函数:
public Text() {
...
}
public static void main(...) {
...
}
可能重复的