問題與java中的對象？

Question

我正在根據用戶輸入yes或no來做出反應的窗口。我遇到了一個問題，在這部分代碼：

public class Mywindow { 

public static void main (String [] args){ 
    windowcontinued object = new windowcontinued(); 
    object.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //ISSUE HERE 
    object.setSize(700, 1024); //ISSUE HERE 
    object.setVisible(true); //ISSUE HERE 
             } 
       } 

這些簡單的操作，應確保在關閉時的程序終止，是具有一定規模，並且是可見的。出於某種原因，雖然，在所有三個操作，我得到錯誤說：

The method setDefaultCloseOperation(int) is undefined for the type windowcontinued 

The method setSize(int, int) is undefined for the type windowcontinued 

The method setVisible(boolean) is undefined for the type windowcontinued 

雖然，所有的這些應該已經導入後確定。下面是完整的代碼：

主要代碼：

package Myguipackage; 

import javax.swing.JOptionPane; 
import javax.swing.JFrame; 
import java.awt.FlowLayout; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import javax.swing.JLabel; 
import javax.swing.JTextField; 

public class Mywindow { 

public static void main (String [] args){ 
    windowcontinued object = new windowcontinued(); 
    object.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    object.setSize(700, 1024); 
    object.setVisible(true); 

             } 
       } 

其他類：

package Myguipackage; 
import javax.swing.JOptionPane; 
import javax.swing.JFrame; 
import java.awt.FlowLayout; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import javax.swing.JLabel; 
import javax.swing.JTextField; 

public class Windowcontinued{ 

public JLabel text; 
public JTextField textfield; 

public windowcontinued(){ //Constructor 
/* super("CHAT"); 
    setLayout(new FlowLayout()); */ 

    text = new JLabel ("Would you like to talk to me?"); 
     text.add(text); 

    textfield = new JTextField ("Yes or no? Erase this and type in your answer!"); 




        } 






class hear implements ActionListener{ 



    public void actionPerformed(ActionEvent event){ 

     String string = ""; 

     if(event.getSource()==textfield) 
      string = String.format("You typed in %s", event.getActionCommand()); 

     JOptionPane.showMessageDialog(null, string); //Open a new window that displays String string, which has changed based on which field you hit enter on. 




                } 



             } 


         } 

使用後FDSA的建議extends關鍵字，這裏是新代碼：

包Myguipackage;

import javax.swing.JFrame; 
import java.awt.FlowLayout; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import javax.swing.JLabel; 
import javax.swing.JTextField; 

public class mywindow extends JFrame{ 

public static void main (String [] args){ 
    windowcontinued object = new windowcontinued(); 
    object.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    object.setSize(700, 1024); 
    object.setVisible(true); 
             } 
       } 

雖然繼續的class window仍然是一樣的。

Answer 1

正如其他海報說的，請在命名類時遵循java命名約定。它使您的代碼更容易遵循。

您似乎對import聲明的目的感到困惑。在導入對象時，只能在該類型的對象上使用它的方法。如果你想讓你的課程模仿現有課程的功能，你需要extend原來的課程，而不僅僅是import它。