单击时如何更改jButton值 [英] How to change jButton value when clicked

问题描述

我在编译时不断出错.

我不知道如何使用列表生成的整数，并在单击后将其显示在jButton中.

I have no idea how to use the list generated integers and display it into the jButtons after clicking.

 public static void Random ()
{
    int Rand [] = new int [49];
    for (int b = 0; b < 49; b++)
        Rand [b] = b;

    List<Integer> alist = Arrays.stream(Rand)
                                        .boxed()
                                        .map (x -> x + 1)
                                        .collect (Collectors.toList());                                 

    Collections.shuffle(alist);
}

private class HandleTextField implements ActionListener
{   
   @Override
   public void actionPerformed(ActionEvent event)
   {
       for (int a = 0; a < 49; a++)
       {
        if (event.getSource() == jbArray[a]) 
        {
            //error on this line "alist cannot be resolved to a variable"
            jbArray[a].setText(alist);
        }   
     }
   }
} 

推荐答案

因此，您在这里遇到两个问题:

So, you have two problems here:

1. alist仅可在您的Random方法内部访问，因为它是一个局部变量，并且已在其中声明.为了解决此问题，您需要使用更大范围声明的列表这里是局部变量的说明.

setText需要输入字符串类型，而列表不是字符串而是列表.如果要访问alist的元素，则可以使用alist.get(yourIndex);

setText requires a String type input and alist is not a string but a list. If you want to access an element of alist then you can use alist.get(yourIndex);

static List<Integer> alist; //is not in random method so it can be accessed by other methods
public static void Random ()
{
int Rand [] = new int [49];
for (int b = 0; b < 49; b++)
    Rand [b] = b;

alist = Arrays.stream(Rand)
                                    .boxed()
                                    .map (x -> x + 1)
                                    .collect (Collectors.toList());                                 

Collections.shuffle(alist);
}


private class HandleTextField implements ActionListener
{   
   @Override
   public void actionPerformed(ActionEvent event)
   {
       for (int a = 0; a < 49; a++)
       {
        if (event.getSource() == jbArray[a]) 
        {
            jbArray[a].setText(alist.get(a)+"");//uses only the element you want rather than all of the list
        }   
     }
   }
}

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