導致運行時錯誤的JOptionPane.showInternalMessageDialog

我試圖讓輸入的速度和角度出現一個框，以及顯示球已被觸發的次數。它給我一個運行時錯誤，我不知道爲什麼。導致該錯誤的部分是JOptionPane.showInternalMessageDialog導致運行時錯誤的JOptionPane.showInternalMessageDialog

import java.awt.Graphics2D; 

import javax.swing.JFrame; 
import javax.swing.JOptionPane; 


public class CannonGame { 

    private static final int WIDTH=800; 
    private static final int HEIGHT=600; 
    private static final int WAIT_TIME=10; 

    public static void main(String[] args) { 
     JFrame frame=new JFrame("Cannon Game"); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     frame.setSize(WIDTH,HEIGHT); 
     MyComponent comp=new MyComponent(); 
     frame.add(comp); 
     frame.setVisible(true); 
     comp.initializeLocations(); 
     frame.repaint(); 
     boolean cont = true; 
     //prompt user for angle and velocity 

     while(cont){ 

      String vel=JOptionPane.showInputDialog(frame,"Enter the Velocity (1-100)"); 
      if(vel == null) 
       System.exit(0); 
      Double velocity=Double.parseDouble(vel); 

      while(velocity < 0 || velocity > 100){ 
       String vel1 = JOptionPane.showInputDialog(frame,"Enter the Velocity (1-100)"); 
       if(vel == null) 
        System.exit(0); 
       Double velocity1 = Double.parseDouble(vel1); 
       velocity = velocity1; 
      } 

      String ang=JOptionPane.showInputDialog(frame,"Enter the angle (0-90)"); 
      if(ang == null) 
       System.exit(0); 
      Double angle=Math.PI*Double.parseDouble(ang)/180.0; 

      while(angle < 0 || angle > 1.57111111111111){ 
       String ang1=JOptionPane.showInputDialog(frame,"Enter the angle (0-90)"); 
       if(ang == null) 
        System.exit(0); 
       Double angle1=Math.PI*Double.parseDouble(ang1)/180.0; 
       angle = angle1; 
      } 


      JOptionPane.showInternalMessageDialog(frame, "Balls fired: " + comp.getNumBallsFired(), 
        "velocity: " + velocity + "angle: " + angle, JOptionPane.INFORMATION_MESSAGE); 

      //animate the cannonball until it hits the ground 
      comp.getReadyForShot(angle,velocity); 
      while(comp.stillInFlight()) { 
       comp.update(System.currentTimeMillis()); 
       frame.repaint(); 
       try { 
        Thread.sleep(WAIT_TIME); 
       } catch (InterruptedException e) { 
        // TODO Auto-generated catch block 
        e.printStackTrace(); 
       } 
      } 

      //print how many tries and if they hit it 
      if(comp.isTargetHit()){ 
       JOptionPane.showMessageDialog(frame, "You fired "+comp.getNumBallsFired()+" times\n and you "+ 
         (comp.isTargetHit()?"":"did not")+" hit the target!"); 

       int answer = JOptionPane.showConfirmDialog(null, 
         "Would you like to fire again?", "choose one", JOptionPane.YES_NO_OPTION); 

       if(answer == JOptionPane.YES_OPTION){ 
        cont = true; 
        comp.initializeLocations(); 
       } 
       else { 
        cont = false; 
        System.exit(0); 
       } 
      }else{ 
       JOptionPane.showMessageDialog(frame, "You fired "+comp.getNumBallsFired()+" times\n and you "+ 
         (comp.isTargetHit()?"":"did not")+" hit the target!"); 

       int answer = JOptionPane.showConfirmDialog(null, 
         "Would you like to fire again?", "choose one", JOptionPane.YES_NO_OPTION); 

       if(answer == JOptionPane.YES_OPTION){ 
        cont = true; 
       } 
       else { 
        cont = false; 
        System.exit(0); 
       } 
      } 

     } 

    } 
}

來源

2014-02-21 user3308067

什麼是錯誤？ – BitNinja

請顯示完整的錯誤信息。這讓我們猜測是糟糕的形式。 –

異常在線程「主」了java.lang.RuntimeException：JOptionPane的：爲父級不必在javax.swing.JOptionPane.showInternalOptionDialog有效的父 \t在javax.swing.JOptionPane.createInternalFrame（JOptionPane.java:1486） \t（ JOptionPane.java:1259） \t在javax.swing.JOptionPane.showInternalMessageDialog（JOptionPane.java:1073） \t在javax.swing.JOptionPane.showInternalMessageDialog（JOptionPane.java:1047） \t在CannonGame.main（CannonGame.java ：54） – user3308067

您必須通過您的JFrame的內容窗格作爲方法中的第一個參數，而不僅僅是您現在正在執行的JFrame。所以，你需要調用你這樣的消息聲明（注意frame.getContentPane()使用，而不僅僅是幀）：

JOptionPane.showMessageDialog(frame.getContentPane(), "You fired "+comp.getNumBallsFired()+" times\n and you "+ 
        (comp.isTargetHit()?"":"did not")+" hit the target!");

參考：Here。

來源

2014-02-21 02:41:23 BitNinja

按照該API，你應該使用showInternalMessageDialog與JInternalFrames，你不會那麼做的。解決方案：不要使用此JOptionPane，而是使用其他更合適的其中一個，如showMessageDialog。

來源

2014-02-21 02:39:28

導致運行時錯誤的JOptionPane.showInternalMessageDialog

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