我在大学里学了几门Java编程课，但是已经有几年了，所以我很生气。我决定问我哥哥的编程任务。他让我写了一个程序来测试口袋妖怪游戏中元素类型的有效性。该代码大部分都适用，但由于某种原因，选项对话框有时是空白的。我有一个标题，但其余的是一个灰色的盒子。对我来说最让人困惑的部分是我之前有一个println（），它在窗格为空时打印正确的短语。
这是我的代码输出：
import javax.swing.JOptionPane;
public class Quiz {
public static void main(String[] args) {
try{
/*creates the matrix of the different types
*and their effectiveness to each other. 0
*represents "Not very effective", 1 is "Neutral"
*2 is "Super effective", 3 is "No Damage"
*/
int[][] myTypeArray =
{{1, 1, 1, 1, 1, 0, 1, 3, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1},
{2, 1, 0, 0, 1, 2, 0, 3, 2, 1, 1, 1, 1, 0, 2, 1, 2, 0},
{1, 2, 1, 1, 1, 0, 2, 1, 0, 1, 1, 2, 0, 1, 1, 1, 1, 1},
{1, 1, 1, 0, 0, 0, 1, 0, 3, 1, 1, 2, 1, 1, 1, 1, 1, 2},
{1, 1, 3, 2, 1, 2, 0, 1, 2, 2, 1, 0, 2, 1, 1, 1, 1, 1},
{1, 0, 2, 1, 0, 1, 2, 1, 0, 2, 1, 1, 1, 1, 2, 1, 1, 1},
{1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 2, 1, 2, 1, 1, 2, 0},
{3, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 0, 1},
{1, 1, 1, 1, 1, 2, 1, 1, 0, 0, 0, 1, 0, 1, 2, 1, 1, 2},
{1, 1, 1, 1, 1, 0, 2, 1, 2, 0, 0, 2, 1, 1, 2, 0, 1, 1},
{1, 1, 1, 1, 2, 2, 1, 1, 1, 2, 0, 0, 1, 1 ,1, 0, 1, 1},
{1, 1, 0, 0, 2, 2, 0, 1, 0, 0, 2, 0, 1, 1, 1, 0, 1, 1},
{1, 1, 2, 1, 3, 1, 1, 1, 1, 1, 2, 0, 0, 1, 1, 0, 1, 1},
{1, 2, 1, 2, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 3, 1},
{1, 1, 2, 1, 2, 1, 1, 1, 0, 0, 0, 2, 1, 1, 0, 2, 1, 1},
{1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 2, 1, 3},
{1, 0, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 0, 0},
{1, 2, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 2, 2, 1}};
//Names for the types
String[] myTypeNamesArray = {"Normal", "Fighting", "Flying", "Poison", "Ground",
"Rock", "Bug", "Ghost", "Steel", "Fire", "Water",
"Grass", "Electric", "Psychic", "Ice", "Dragon",
"Dark", "Fairy"};
//loops the message panes until they get a wrong answer
for(int i = 0; i > -1; i++){
//Two integers to randomly select one of the 18 different types
int num1 = (int)(Math.random()*18);
int num2 = (int)(Math.random()*18);
//Creates JOptionPane to show the two randomed types and get input
//Name of the buttons
Object[] buttons = { "Not Very Effective", "Neutral", "Super Effective", "No Damage" };
//Test output for asking them how effective type 1 is vs type 2
System.out.println(num1 + " " + num2 + " " + "How effective is " +
myTypeNamesArray[num1] + " against " + myTypeNamesArray[num2] + "? " +
"the answer was " + (String)buttons[myTypeArray[num1][num2]] + ". " + i);
// **HERE IS WHERE THE MESSAGE IS BLANK SOMETIMES**
int answer = JOptionPane.showOptionDialog(null, "How effective is " +
myTypeNamesArray[num1] + " against " + myTypeNamesArray[num2] + "?",
"Pokemon Type Effectiveness Quiz", JOptionPane.DEFAULT_OPTION,
JOptionPane.QUESTION_MESSAGE, null, buttons, buttons[0]);
//Test their answers
if(answer == myTypeArray[num1][num2]){
} else if(!(answer == myTypeArray[num1][num2])) {
// **THIS IS ALSO BLANK SOMETIMES **
JOptionPane.showMessageDialog(null, "Sorry, the answer was " +
(String)buttons[myTypeArray[num1][num2]] + ". You said " +
buttons[answer] + "\nYou got " + i + " correct.");
break;
} else {
break;
}
}
} catch (Exception e) {
System.out.println("The error was " + e);
}
}//end main
}
答案 0 :(得分：2)
问题的间歇性表明存在线程问题。尝试在Swing事件线程上运行代码。类似的东西：
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
doOnEventThread();
}
});
}
public static void doOnEventThread() {
try{
/*creates the matrix of the different types
*and their effectiveness to each other. 0
*represents "Not very effective", 1 is "Neutral"
*2 is "Super effective", 3 is "No Damage"
*/
int[][] myTypeArray =
{{1, 1, 1, 1, 1, 0, 1, 3, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1},
{2, 1, 0, 0, 1, 2, 0, 3, 2, 1, 1, 1, 1, 0, 2, 1, 2, 0},
{1, 2, 1, 1, 1, 0, 2, 1, 0, 1, 1, 2, 0, 1, 1, 1, 1, 1},
{1, 1, 1, 0, 0, 0, 1, 0, 3, 1, 1, 2, 1, 1, 1, 1, 1, 2},
{1, 1, 3, 2, 1, 2, 0, 1, 2, 2, 1, 0, 2, 1, 1, 1, 1, 1},
{1, 0, 2, 1, 0, 1, 2, 1, 0, 2, 1, 1, 1, 1, 2, 1, 1, 1},
{1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 2, 1, 2, 1, 1, 2, 0},
{3, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 0, 1},
{1, 1, 1, 1, 1, 2, 1, 1, 0, 0, 0, 1, 0, 1, 2, 1, 1, 2},
{1, 1, 1, 1, 1, 0, 2, 1, 2, 0, 0, 2, 1, 1, 2, 0, 1, 1},
{1, 1, 1, 1, 2, 2, 1, 1, 1, 2, 0, 0, 1, 1 ,1, 0, 1, 1},
{1, 1, 0, 0, 2, 2, 0, 1, 0, 0, 2, 0, 1, 1, 1, 0, 1, 1},
{1, 1, 2, 1, 3, 1, 1, 1, 1, 1, 2, 0, 0, 1, 1, 0, 1, 1},
{1, 2, 1, 2, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 3, 1},
{1, 1, 2, 1, 2, 1, 1, 1, 0, 0, 0, 2, 1, 1, 0, 2, 1, 1},
{1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 2, 1, 3},
{1, 0, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 0, 0},
{1, 2, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 2, 2, 1}};
//Names for the types
String[] myTypeNamesArray = {"Normal", "Fighting", "Flying", "Poison", "Ground",
"Rock", "Bug", "Ghost", "Steel", "Fire", "Water",
"Grass", "Electric", "Psychic", "Ice", "Dragon",
"Dark", "Fairy"};
//loops the message panes until they get a wrong answer
for(int i = 0; i > -1; i++){
//Two integers to randomly select one of the 18 different types
int num1 = (int)(Math.random()*18);
int num2 = (int)(Math.random()*18);
//Creates JOptionPane to show the two randomed types and get input
//Name of the buttons
Object[] buttons = { "Not Very Effective", "Neutral", "Super Effective", "No Damage" };
//Test output for asking them how effective type 1 is vs type 2
System.out.println(num1 + " " + num2 + " " + "How effective is " +
myTypeNamesArray[num1] + " against " + myTypeNamesArray[num2] + "? " +
"the answer was " + (String)buttons[myTypeArray[num1][num2]] + ". " + i);
// **HERE IS WHERE THE MESSAGE IS BLANK SOMETIMES**
int answer = JOptionPane.showOptionDialog(null, "How effective is " +
myTypeNamesArray[num1] + " against " + myTypeNamesArray[num2] + "?",
"Pokemon Type Effectiveness Quiz", JOptionPane.DEFAULT_OPTION,
JOptionPane.QUESTION_MESSAGE, null, buttons, buttons[0]);
//Test their answers
if(answer == myTypeArray[num1][num2]){
} else if(!(answer == myTypeArray[num1][num2])) {
// **THIS IS ALSO BLANK SOMETIMES **
JOptionPane.showMessageDialog(null, "Sorry, the answer was " +
(String)buttons[myTypeArray[num1][num2]] + ". You said " +
buttons[answer] + "\nYou got " + i + " correct.");
break;
} else {
break;
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
修改
有关Swing的事件线程和线程问题的更多信息，请查看文章Concurrency in Swing。但是要重新进行迭代，每当你发现自己遇到间歇性的程序错误行为时，这种情况不会一直发生，请考虑“线程问题”。