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[英]Is it possible to determine the classname of an outer class from an instance of an anonymous inner class
[英]Refer the outer instance of the anonymous class from an inner anonymous class
在以下代码段中:
public void main(){
//Enclosing scope
final TextField field = new TextField("", uiSkin) {
@Override
protected InputListener createInputListener() {
return new TextFieldClickListener() {
@Override
public boolean keyUp(com.badlogic.gdx.scenes.scene2d.InputEvent event, int keycode) {
// error1 => The local variable field may not have been initialized
System.out.println("Field "+field+"event="+event+" key={}"+keycode);
// error2 => No enclosing instance of the type TextField is accessible in scope
System.out.println("Field "+TextField.this+"event="+event+" key={}"+keycode);
return super.keyUp(event, keycode);
};
};
}
};
}
有没有办法从内部匿名类中引用匿名类的外部实例?
第二个错误出现在我在这里找到的解决方案中,来自匿名内部类的外部类的关键字 。 似乎问题共享一些概念和问题空间,但性质不同。
可以通过定义一个新字段来修复问题,该字段捕获对封闭它的引用。
//Enclosing scope
final TextField field = new TextField("", uiSkin) {
TextField this2 = this;
@Override
protected InputListener createInputListener() {
return new TextFieldClickListener() {
@Override
public boolean keyUp(com.badlogic.gdx.scenes.scene2d.InputEvent event, int keycode) {
System.out.println("Field "+this2+"event="+event+" key={}"+keycode);
return super.keyUp(event, keycode);
};
};
}
};
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