从实例化对象在主类中调用方法

Question

我想做的是这样的：

public class MainClass {
    private UIController uIController;

    MainClass() {
        uIController = new UIController();
    }

    public void MethodIWantToCall() {
        //Do Something
    }
}

UIController类的示例：

public class UIController {
    UIController() {
        //Call a method in MainClass here, for example MethodIWantToCall()
    }

    public void MethodA {
        //Call a method in MainClass here, for example MethodIWantToCall()
    }
}

我想做的是将UIController传递给MainClass命令，在用户与UI交互时调用其方法或将值返回给MainClass。

Answer 1

您需要将MainClass实例的引用传递给UIController实例，例如：

public class UIController {
    private final MainClass mainClass;
    UIController (final MainClass mainClass) {
         this.mainClass = mainClass;
         //Call a method in MainClass here, for example MethodIWantToCall()
         this.mainClass.MethodIWantToCall();
    }

    public void MethodA() {
        //Call a method in MainClass here, for example MethodIWantToCall()
         this.mainClass.MethodIWantToCall();             
    }
}

然后

uIController = new UIController(this);

PS：Java中的方法应以小写字母开头。

Answer 2

您可以创建实例字段：

public class MainClass {
    public static MainClass instance;
    public MainClass() {
        instance=this;
    }
    public void method() {}
}

然后，调用：MainClass.instance.method（）; 要么：

public class MainClass {
    public MainClass() {
        new AnotherClass(this);
    }
    public void method() {}
}
public class AnotherClass {
    public AnotherClass(MainClass main) {
        main.method();
    }
}