java - Java中如何初始化匿名内部类

Question

有什么方法可以在 Java 中初始化匿名内部类？

例如:

new AbstractAction() {
    actionPerformed(ActionEvent event) {
    ...
    }
}

有什么方法可以在类声明的某处使用例如 putValue 方法吗？

Answer 1

使用初始化 block :

new AbstractAction() {

    {
        // do stuff here
    }

    public void actionPerformed(ActionEvent event) {
    ...
    }
}

---

初始化实例成员

Normally, you would put code to initialize an instance variable in a constructor. There are two alternatives to using a constructor to initialize instance variables: initializer blocks and final methods. Initializer blocks for instance variables look just like static initializer blocks, but without the static keyword:

{
    // whatever code is needed for initialization goes here
}

The Java compiler copies initializer blocks into every constructor. Therefore, this approach can be used to share a block of code between multiple constructors.

来源:

• Java Tutorial > InitializingFields