以下代码是项目的动作侦听器。基本上,我有4个单选按钮,当我点击一个时,我希望它在屏幕上更改变量。当我运行代码时,它只是将所有值加在一起。还有其他方法吗?
class Calc implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
double base = 0.00;
double options;
double total;
if (Button25.isSelected());
{
base = base + 999.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
if (Button32.isSelected());
{
base = base + 1049.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
if (Button35.isSelected());
{
base = base + 1099.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
if (Button42.isSelected());
{
base = base + 1155.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
}
}
答案 0 :(得分:2)
问题在于,对于每个if()
语句,例如 if(Button32.isSelected()); ,最后会有一个;
符号。这不应该存在。这是更正后的代码......
class Calc implements ActionListener {
public void actionPerformed(ActionEvent event){
double base = 0.00;
double options;
double total;
if (Button25.isSelected()){ // changed
base = base + 999.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
else if (Button32.isSelected()){ // changed
base = base + 1049.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
else if (Button35.isSelected()){ // changed
base = base + 1099.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
else if (Button42.isSelected()){ // changed
base = base + 1155.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
}
}
作为替代方案,为什么不从ActionEvent
获取单击的按钮,然后使用if-else分支中的按钮...
class Calc implements ActionListener {
public void actionPerformed(ActionEvent event){
double base = 0.00;
double options;
double total;
Object clickedObject = event.getSource();
if (clickedObject instanceof JRadioButton){
JRadioButton clickedButton = (JRadioButton)clickedObject;
if (clickedButton == Button25){
base = base + 999.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
else if (clickedButton == Button32){
base = base + 1049.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
else if (clickedButton == Button35){
base = base + 1099.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
else if (clickedButton == Button42){
base = base + 1155.99;
String base2 = Double.toString(base);
lblBaseAns.setText(base2);
}
}
}
}