java - 如何与另一件 JComboBox 元素交换？

Question

我正在尝试制作一个货币转换器程序，并且我希望 JComboBox 项目从其他 JComboBox when I hit the convert button. 中替换

我知道错误是尝试将字符串转换为整数，但我看不到其他方法来设置 JComboBox 的内容。

A screenshot from NetBeans with my results in case the code is hard to understand.

下面是jButton的代码:

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
                try {
              for(int a = 0; a < 4; a++){
                String box2 = (currency2.getItemAt(a));
            System.out.println("List items b4 conversion, JComboBox1: "+ currency1.getItemAt(a));
            System.out.println("List items b4 conversion, JComboBox2: "+ box2+"\n");
            System.out.println("--End of first 2 items--");
System.out.println("JComboBox2 after conv" +currency1.getItemAt(Integer.parseInt(box2)));
                }

                    }catch (NumberFormatException e){
                        System.out.println("error");
                }    
    }

打印的内容如下:

List items b4 conversion, JComboBox1: EUR
List items b4 conversion, JComboBox2: ALL

--End of first 2 items--
error

同时，当我删除: System.out.println("JComboBox2 after conv"+currency1.getItemAt(Integer.parseInt(box2))) 时，它会按预期打印 2 个 JComboBox 的所有项目.

Answer 1

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
    String txt1 = (String) JComboBox1.getSelectedItem();
    String txt2 = (String) JComboBox2.getSelectedItem();
    jComboBox1.setSelectedItem(txt2);
    jComboBox2.setSelectedItem(txt1);
}