java 如何在Java中初始化匿名内部类
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How to initialize anonymous inner class in Java
提问by Jarek
Is there any way to initialize anonymous inner class in Java?
有没有办法在Java中初始化匿名内部类？
For example:
例如：
new AbstractAction() {
actionPerformed(ActionEvent event) {
...
}
}
Is there any way to use for example putValue method somewhere in the class declaration?
有没有办法在类声明中的某处使用例如 putValue 方法？
回答by Sean Patrick Floyd
Use an Initializer Block:
使用初始化块：
new AbstractAction() {
{
// do stuff here
}
public void actionPerformed(ActionEvent event) {
...
}
}
Initializing Instance Members
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:
通常，您会在构造函数中放置用于初始化实例变量的代码。使用构造函数初始化实例变量有两种替代方法：初始化块和最终方法。实例变量的初始化块看起来就像静态初始化块，但没有 static 关键字：
{
// 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.
Java 编译器将初始化块复制到每个构造函数中。因此，这种方法可用于在多个构造函数之间共享代码块。
Source:
来源：
回答by Jon Skeet
It's not quite clear what you mean, but you can use an initializer blockto execute code at construction time:
不是很清楚你的意思，但你可以在构造时使用初始化块来执行代码：
new AbstractAction() {
{
// This code is called on construction
}
@Override public void actionPerformed(ActionEvent event) {
...
}
}
回答by weekens
You can use the instance initialization section:
您可以使用实例初始化部分：
new AbstractAction() {
{
//initialization code goes here
}
actionPerformed(ActionEvent event) {
...
}
}
回答by Philipp Hügelmeyer
Or you can just access the variables of the outer class from the inner class.
或者你可以只从内部类访问外部类的变量。
http://en.wikibooks.org/wiki/Java_Programming/Nested_Classes#Anonymous_Classes
http://en.wikibooks.org/wiki/Java_Programming/Nested_Classes#Anonymous_Classes
