Java 在单独的类上添加 ActionListener
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Java add ActionListener on a separate class
提问by Ewen
Heres what I want to do, one of the classes is for a JFrame which contains all JButtons, I want another class to listen for the actions made on the JFrame class. See the code below:
这是我想要做的，其中一个类用于包含所有 JButton 的 JFrame，我想要另一个类来侦听在 JFrame 类上所做的操作。请参阅下面的代码：
public class Frame extends JFrame{
//all the jcomponents in here
}
public class listener implements ActionListener{
//listen to the actions made by the Frame class
}
Thanks for your time.
谢谢你的时间。
回答by JeffS
Just add a new instance of your listener to whatever components you want to listen. Any class that implements ActionListenercan be added as a listener to your components.
只需将您的监听器的新实例添加到您想要监听的任何组件中即可。任何实现的类ActionListener都可以作为侦听器添加到您的组件中。
public class Frame extends JFrame {
JButton testButton;
public Frame() {
testButton = new JButton();
testButton.addActionListener(new listener());
this.add(testButton);
}
}
回答by Kumar Vivek Mitra
1.You can use Inner Class, or Anonymous Inner Classto solve this....
1.您可以使用Inner Class, 或Anonymous Inner Class来解决这个问题....
Eg:
例如：
Inner Class
内部类
public class Test{
Button b = new Button();
class MyListener implements ActionListener{
public void actionPerformed(ActionEvent e) {
// Do whatever you want to do on the button click.
}
}
}
Eg:
例如：
Anonymous Inner Class
匿名内部类
public class Test{
Button b = new Button();
b.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
// Do whatever you want to do on the button click.
}
});
}
回答by olagjo
If you want one and the same instance of listenerto listen to all of the buttons in the frame, you would have to make the actionPerformed method collect all clicks and delegate based on command:
如果您希望同一个 的实例listener侦听框架中的所有按钮，则必须使 actionPerformed 方法收集所有点击并基于命令进行委托：
public class listener extends ActionListener{
public void actionPerformed(ActionEvent e){
String command = e.getActionCommand();
if (command.equals("foo")) {
handleFoo(e);
} else if (command.equals("bar")) {
handleBar(e);
}
}
private void handleFoo(ActionEvent e) {...}
private void handleBar(ActionEvent e) {...}
}
which will become easier in Java 7, where you can switch over strings!
The ActionCommand of a button click will be the Text-attribute of the JButton, unless you set it otherwise
这将在 Java 7 中变得更容易，您可以在其中切换字符串！点击一个按钮的ActionCommand将是Text的-attribute JButton，除非你设置它，否则
