塗料方法（joption窗格）

Question

幫助IM沮喪的鍵盤輸入，不能找到用於joption窗格中輸入掃描方法。我需要從對話框中讀取用戶輸入，但是我的in = a.nextInt失敗。這要是以後（輸入= 1），一定的形狀會被吸引，什麼是掃描對話框中輸入誰能幫助

import java.awt.*; 
import javax.swing.*; 
import java.util.Scanner; 
public class Paint extends JPanel { 


public Paint() { 

    Scanner a = new Scanner(System.in); 
    in = a.nextInt(JOptionPane.showInputDialog("Please enter number: ")); 

    setBackground(Color.WHITE); 

} 
public void paintComponent(Graphics g){ 
    super.paintComponent(g); 



    if(in == 1){ 
    g.setColor(Color.BLACK); 
    g.drawLine(400, 400, 400, 350); 
    g.drawLine(400, 350, 350, 350); 
    } 
} 
} 

Answer 1

使用未來建設的代碼：

int in = -1; 
String showInputDialog = JOptionPane.showInputDialog("Please enter number: "); 
try{ 
    in = Integer.valueOf(showInputDialog); 
} catch (Exception e){ 
    e.printStackTrace(); 
} 

，而不是

Scanner a = new Scanner(System.in); 
in = a.nextInt(JOptionPane.showInputDialog("Please enter number: "));