我想在动作监听器中使用变量。 这是我的代码:
public class Face {
public Face(){
Btn1 = new JToggleButton();
Btn2 = new JToggleButton();
Btn3 = new JToggleButton();
Btn4 = new JToggleButton();
Btn5 = new JToggleButton();
Btn6 = new JToggleButton();
}
public Start6(){
JToggleButton[] Btn = new javax.swing.JToggleButton[5]; // An array for saving address of all buttons
Btn[0] = Btn1 ;
Btn[1] = Btn2 ;
Btn[2] = Btn3 ;
Btn[3] = Btn4 ;
Btn[4] = Btn5 ;
Btn[5] = Btn6 ;
for (int i = 0 ; i < 36 ; i++) {
Btn[i].addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
Btn[i].setSize(150, 150);
ImageIcon BtnImage = new ImageIcon(getClass().getResource("/GameImages/" + /* a picture name*/ + ".jpg" ));
Image img = BtnImage.getImage();
Btn[i].setIcon( new ImageIcon(img.getScaledInstance(225,160 ,Image.SCALE_FAST)));
X6P.add(Btn[i]);
}
});
}
}
public javax.swing.JToggleButton Btn1;
public javax.swing.JToggleButton Btn2;
public javax.swing.JToggleButton Btn3;
public javax.swing.JToggleButton Btn4;
public javax.swing.JToggleButton Btn5;
}
当我想在Btn数组(相同数组)的动作侦听器中使用Btn数组时,我收到此错误:
从内部类引用的局部变量必须是最终的或有效的最终 我想要点击按钮时显示它的图标......
答案 0 :(得分:1)
错误意味着它所说的内容:您的数组变量Btn
不是final
,因此无法从内部类访问它。制作final
将解决问题:
final JToggleButton[] Btn = new ...
另一个解决方案是将数组移动到类中:
public javax.swing.JToggleButton Btn1;
public javax.swing.JToggleButton Btn2;
public javax.swing.JToggleButton Btn3;
public javax.swing.JToggleButton Btn4;
public javax.swing.JToggleButton Btn5;
private javax.swing.JToggleButton[] Btn = new javax.swing.JToggleButton[] {
Btn1, Btn2, Btn3, Btn4, Btn5
};
这会做同样的事情,让你的代码缩短。
我想要点击按钮时显示其图标
您根本不需要使用数组:而不是引用Btn[i]
,引用e.getSource()
。它被设置为已被点击的按钮 - 您需要做的就是投射它:
javax.swing.JToggleButton sender = (javax.swing.JToggleButton)e.getSource();
在循环外创建一个动作侦听器 ,并在所有按钮上设置它。这将完全消除阵列:
// The same listener instance can handle all buttons
ActionListener actListener = new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
javax.swing.JToggleButton senderButton = (javax.swing.JToggleButton)e.getSource();
... // Do anything you want with senderButton here
}
};
// Add the same listener to all buttons
for (int i = 0 ; i < 36 ; i++) {
Btn[i].addActionListener(actListener);
}