GUI Loop问题Java

我是一个尝试使用基本的GUI函数为练习中的前56个元素制作简单问题和回答程序的新手。GUI Loop问题Java

但是，当我运行我的代码时，我得到随机代码运行期间的错误。

一个文本框将出现没有对话只是消息作为文本框的名称，并X按钮退出。有时当我按下X时，它会转到我代码中的下一行，其他时候它会退出。因为它似乎是随机发生的，所以我很难重现这个错误。

我的主要方法是下面贴：

import java.math.*; 
import java.text.DecimalFormat; 
import java.io.*; 
import java.util.*; 
import javax.swing.JOptionPane; 
import java.util.Random; 

//This lab is to study periodc table of elements with simple gui output 
public class practiceFiftyEight 
{ 
public static void main(String[] args) 
{ 

    String input; 

    boolean answer; 

    Random myRan = new Random(); 

    int randInt = 0; 
    //random num from 0 - 56 

    String[] arrayElements = {"Hydrogen","Helium","Lithium","Beryllium","Boron","Carbon","Nitrogen","Oxygen","Fluorine","Neon","Sodium","Mangnesium","Aluminium","Silicon","Phosphorus","Sulfur","Chlorine","Argon","Potassium","Calcium","Scandium","Titanium","Vanadium","Chronium","Manganese","Iron","Cobalt","Nickel","Copper","Zinc", 
    "Gallium","Germanium","Arsenic","Selenium","Bromine","Krypton","Rubidium","Strontium","Yttrium","Zirconium","Niobium","Molybdenum","Technetium","Ruthenium","Rhodium","Palladium","Silver","Cadmium","Indium","Tin","Antimony","Tellurium","Iodine","Xenon","Cesium","Barium"}; 

    String[] arrayEleAbriv = {"H","He","Li","Be","B","C","N","O","F","Ne","Na","Mg","Al","Si","P","S","Cl","Ar","K","Ca","Sc","Ti","V","Cr","Mn","Fe","Co","Ni","Cu","Zn","Ga","Ge","As", 
    "Se","Br","Kr","Rb","Sr","Y","Zr","Nb","Mo","Tc","Ru","Rh","Pd","Ag","Cd","In","Sn","Sb","Te","I","Xe","Cs","Ba"}; 

    int repeat; 

     do 
     { 
     randInt = myRan.nextInt(56); 

     JOptionPane.showMessageDialog(null, " sizes of arrays " + arrayElements.length + " " + arrayEleAbriv.length); 

     JOptionPane.showMessageDialog(null, " What is the symbol of " + arrayElements[randInt]); 

     input = JOptionPane.showInputDialog(null," Enter element symbol (1 - 56) of"); 

     answer = input.equalsIgnoreCase(arrayEleAbriv[randInt]); 

     if(answer) 
     { 
     JOptionPane.showMessageDialog(null, " Correct " + arrayElements[randInt] + " is represented by " + arrayEleAbriv[randInt]); 
     } 
     else 
     { 
      JOptionPane.showMessageDialog(null, " WRONG!!!!! " + arrayElements[randInt] + " is represented by " + arrayEleAbriv[randInt] + " !!!!! "); 
     } 
     repeat = JOptionPane.showConfirmDialog(null, "Press Yes to repeat, No to quit ", "please confirmm", JOptionPane.YES_NO_OPTION); 

     }while(repeat == JOptionPane.YES_OPTION); 
    } 
}

来源

2014-09-10 Ro Siv

镁被拼写为“Mangnesium”。将变量声明为更接近它们的用法可能会更好，例如，使用“输入”和“答案”。我想知道，因为这个类被命名为'practiceFiftyEight'，并且每次在循环中打印数组的大小，但是只有56个元素被支持，如果问题与您的程序的早期版本有关没有匹配？我试过了，无法重现任何错误。 – 2014-09-10 16:57:58

你有什么记录吗？ – m4rtin 2014-09-10 16:59:15

您还有几个未使用的导入。这将是一个好主意，从文件中读取元素数据，而不是硬编码所有内容，但我意识到这仅仅是一个开始。 – 2014-09-10 16:59:18

你应该从EDT调用Swing组件。

如果用户选择了取消，那么也有可能抛出NullPointerException的地方。

以下代码应该不会冻结。

import java.text.DecimalFormat; 
import javax.swing.SwingUtilities; 
import javax.swing.JOptionPane; 
import java.util.Random; 

//This lab is to study periodc table of elements with simple gui output 
public class PracticeFiftyEight { 
    final static String[] arrayElements = {"Hydrogen","Helium","Lithium","Beryllium","Boron","Carbon","Nitrogen","Oxygen","Fluorine","Neon","Sodium","Magnesium", 
              "Aluminium","Silicon","Phosphorus","Sulfur","Chlorine","Argon","Potassium","Calcium","Scandium","Titanium","Vanadium", 
              "Chromium","Manganese","Iron","Cobalt","Nickel","Copper","Zinc","Gallium","Germanium","Arsenic","Selenium","Bromine", 
              "Krypton","Rubidium","Strontium","Yttrium","Zirconium","Niobium","Molybdenum","Technetium","Ruthenium","Rhodium", 
              "Palladium","Silver","Cadmium","Indium","Tin","Antimony","Tellurium","Iodine","Xenon","Cesium","Barium"}; 

    final static String[] arrayEleAbriv = {"H","He","Li","Be","B","C","N","O","F","Ne","Na","Mg","Al","Si","P","S","Cl","Ar","K","Ca","Sc","Ti","V","Cr","Mn","Fe","Co","Ni","Cu","Zn","Ga","Ge","As", 
       "Se","Br","Kr","Rb","Sr","Y","Zr","Nb","Mo","Tc","Ru","Rh","Pd","Ag","Cd","In","Sn","Sb","Te","I","Xe","Cs","Ba"}; 

    public static void main(String[] args) {    

     SwingUtilities.invokeLater(new Runnable() { 
      public void run() { 

       String input; 

       boolean answer; 

       Random myRan = new Random(); 

       int randInt = 0; 
       //random num from 0 - 56     

       int repeat; 

       do { 
        randInt = myRan.nextInt(56); 

        JOptionPane.showMessageDialog(null, " sizes of arrays " + arrayElements.length + " " + arrayEleAbriv.length); 

        JOptionPane.showMessageDialog(null, " What is the symbol of " + arrayElements[randInt]); 

        input = JOptionPane.showInputDialog(null," Enter element symbol (1 - 56) of"); 

        if(input != null) { // if user press cancel, input is null 
         answer = input.equalsIgnoreCase(arrayEleAbriv[randInt]); 

         if(answer) { 
          JOptionPane.showMessageDialog(null, " Correct " + arrayElements[randInt] + " is represented by " + arrayEleAbriv[randInt]); 
         } else { 
          JOptionPane.showMessageDialog(null, " WRONG!!!!! " + arrayElements[randInt] + " is represented by " + arrayEleAbriv[randInt] + " !!!!! "); 
         } 
        } else { 
         System.out.println("input is null: " + input); 
        } 

        repeat = JOptionPane.showConfirmDialog(null, "Press Yes to repeat, No to quit ", "please confirmm", JOptionPane.YES_NO_OPTION); 

       } while(repeat == JOptionPane.YES_OPTION); 
      } 
     }); 
    } 
}

来源

2014-09-11 16:25:49 MockerTim

GUI Loop问题Java

回答

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