Java 在用户输入不正确时使用JOptionPane循环
我正在用java模拟一个彩票游戏。现在一切正常,我只验证用户输入数字1到100>我还想阻止用户输入和清空值。现在正在使用try。。接住但这只是第一次起作用。用户输入6个数字。假设第一个输入为空,则会显示错误,但如果用户在空输入上再次按enter键,程序将崩溃。我无法让它循环,我尝试了好几件事,但都没有成功。下面是获取用户输入的代码Java 在用户输入不正确时使用JOptionPane循环,java,Java,我正在用java模拟一个彩票游戏。现在一切正常,我只验证用户输入数字1到100>我还想阻止用户输入和清空值。现在正在使用try。。接住但这只是第一次起作用。用户输入6个数字。假设第一个输入为空,则会显示错误,但如果用户在空输入上再次按enter键,程序将崩溃。我无法让它循环,我尝试了好几件事,但都没有成功。下面是获取用户输入的代码 String [] charNums = {"1st","2nd","3rd","4th","5th","Bonus"}; //get input 5 numbers
String [] charNums = {"1st","2nd","3rd","4th","5th","Bonus"};
//get input 5 numbers from user
for(int i=0; i<6;i++){
//boolean correctInput = false;
//while(!correctInput){
try {
inputNumbers[i] = Integer.parseInt(JOptionPane.showInputDialog("Enter "+charNums[i]+" number from 1 to 100"));
while(!validate(inputNumbers[i])){
JOptionPane.showMessageDialog(null,"Invalid Number! try Again","ERROR",JOptionPane.ERROR_MESSAGE);
inputNumbers[i] = Integer.parseInt(JOptionPane.showInputDialog("Enter "+charNums[i]+" number from 1 to 100"));
}
////check for duplicate entries from user
for (int k=0; k<i; k++) {
while (k!=i && inputNumbers[k] == inputNumbers[i]) {
JOptionPane.showMessageDialog(null,"Duplicate Entry! try again","ERROR",JOptionPane.ERROR_MESSAGE);
inputNumbers[i] = Integer.parseInt(JOptionPane.showInputDialog("Enter "+charNums[i]+" number from 1 to 100"));
}
}
//correctInput = true;
//break;
}catch (NumberFormatException e) {
JOptionPane.showMessageDialog(null,"Number not entered! try Again","ERROR",JOptionPane.ERROR_MESSAGE);
//throw new NumberFormatException("not number");
inputNumbers[i] = Integer.parseInt(JOptionPane.showInputDialog("Enter "+charNums[i]+" number from 1 to 100"));
//correctInput = false;
//JOptionPane.setValue(JOptionPane.UNINITIALIZED_VALUE);
//continue;
//}
}
userNumbers[i] = inputNumbers[i];
}
试一下
boolean correctInput = false;
///create array to display user
String [] charNums = {"1st","2nd","3rd","4th","5th","Bonus"};
//get input 5 numbers from user
for(int i=0; i<6;i++){
do {
try {
inputNumbers[i] = Integer.parseInt(JOptionPane.showInputDialog("Enter "+charNums[i]+" number from 1 to 100"));
while(!validate(inputNumbers[i])){
JOptionPane.showMessageDialog(null,"Invalid Number! try Again","ERROR",JOptionPane.ERROR_MESSAGE);
inputNumbers[i] = Integer.parseInt(JOptionPane.showInputDialog("Enter "+charNums[i]+" number from 1 to 100"));
}
////check for duplicate entries from user
for (int k=0; k<i; k++) {
while (k!=i && inputNumbers[k] == inputNumbers[i]) {
JOptionPane.showMessageDialog(null,"Duplicate Entry! try again","ERROR",JOptionPane.ERROR_MESSAGE);
inputNumbers[i] = Integer.parseInt(JOptionPane.showInputDialog("Enter "+charNums[i]+" number from 1 to 100"));
}
}
correctInput = true;
//break;
}catch (NumberFormatException e) {
JOptionPane.showMessageDialog(null,"Number not entered! try Again","ERROR",JOptionPane.ERROR_MESSAGE);
//throw new NumberFormatException("not number");
inputNumbers[i] = Integer.parseInt(JOptionPane.showInputDialog("Enter "+charNums[i]+" number from 1 to 100"));
correctInput = false;
//JOptionPane.setValue(JOptionPane.UNINITIALIZED_VALUE);
//continue;
}
}while(!correctInput);
userNumbers[i] = inputNumbers[i];
}
try/catch应该在while循环中,否则在抛出异常时退出循环
提示:do/while。这里是您的代码修改,使循环6个数字变得更加简单,我已经测试过了,它运行良好。如果有什么不清楚,请告诉我
String [] charNums = {"1st","2nd","3rd","4th","5th","Bonus"};
int[] inputNumbers = new int[6];
//get input 6 numbers from user
int cnt = 0;
while(true)
{
try
{
String tmp = JOptionPane.showInputDialog("Enter "+charNums[cnt]+" number from 1 to 100");
int val = Integer.parseInt(tmp);
boolean duplicate = false;
for (int k=0; k<cnt; k++)
{
if(val==inputNumbers[k])
{
JOptionPane.showMessageDialog(null,"Duplicate Entry! try again","ERROR",JOptionPane.ERROR_MESSAGE);
duplicate = true;
break;
}
}
if(duplicate)continue;
inputNumbers[cnt] = val;
cnt++;
}
catch(Exception e)
{
}
if(cnt==6)break;
}
上面的代码对我不起作用。但是我通过将try-and-catch放在validate方法中进行了修复,现在每当有错误的输入时,它都会循环。这是密码
public static boolean validate(String num){
try {
int convertedNum = Integer.parseInt(num);
if(convertedNum < 0 || convertedNum > 100){
return false;
}else{
return true;
}
}catch ( NumberFormatException e){
return false;
}
}
for(int i=0; i<6;i++){
inputNumbers[i] = JOptionPane.showInputDialog("Enter "+charNums[i]+" number from 1 to 100");
while(!validate(inputNumbers[i])){
if(inputNumbers[i] == null){
int stopGame = JOptionPane.showConfirmDialog(null,"Do you wish to cancel the game? All progress will be lost","",JOptionPane.YES_NO_OPTION);
if(stopGame == JOptionPane.YES_OPTION){
System.exit(0);
}
}
JOptionPane.showMessageDialog(null,"Invalid Number! try Again","ERROR",JOptionPane.ERROR_MESSAGE);
inputNumbers[i] = JOptionPane.showInputDialog("Enter "+charNums[i]+" number from 1 to 100");
}
////check for duplicate entries from user
for (int k=0; k<i; k++) {
while (k!=i && Integer.parseInt(inputNumbers[k]) == Integer.parseInt(inputNumbers[i])) {
JOptionPane.showMessageDialog(null,"Duplicate Entry! try again","ERROR",JOptionPane.ERROR_MESSAGE);
inputNumbers[i] = JOptionPane.showInputDialog("Enter "+charNums[i]+" number from 1 to 100");
}
}
//convert string to int
userNumbers[i] = Integer.parseInt(inputNumbers[i]);
}
你是说在里面!验证循环?是的,这就是我的意思。想一想,这很简单。我可以给你解决方案,但如果你自己解决它,你将学会更多如何思考编程,并感到更有成就感;请看我在答案中的暗示。我知道我已经做了一整天了,也许你能解释一下“捉迷藏”是如何起作用的?我会了解更多的。我将发布我现在所拥有的。Netbeans告诉我,correctInput从未被使用过,如果我了解try-and-catch的工作原理,我可能会想出答案