将类变量传递给另一个类 [英] Pass a class variable to another class

问题描述

我想将一个类变量传递给另一个类，并使其成为该类的类变量。我将如何在以下上下文中执行此操作？

I'd like to pass a class variable to another class and make it a class variable of that class. How would I do this in the following context?

        public class GLCamTest extends Activity {
public float array[] = something;
  }

  class GLLayer extends GLSurfaceView implements SurfaceHolder.Callback,
  Camera.PreviewCallback, Renderer {
  //Get class variable here
 }

推荐答案

很难理解你问的问题，但这里有可能回答：

It is difficult to understand wjat you are asking, but here's a possible answer:

使B类成为A的子类：

    public class A {
        // Declaration of the 'array' attribute
        public float[] array = new float[]{1.1f, 2.2f, 3.3f};

    }

    class B extends A {
        // Every instance of 'B' also has an 'array' attribute
    }

如果数组重新声明为 public static ，你会遇到一个 array 属性的情况，可以称为 A.array 或 B.array 。 （或者在 A 或 B 内，只需数组。 ..或者甚至作为 a.array 或 b.array 其中 a 和 b 分别具有类型 A 和 B 。）

If array is redeclared to be public static, you get a situation where there is an array attribute that can be referred to as A.array or B.array. (Or within either A or B as just array ... or even as a.array or b.array where a and b have types A and B respectively.)

如果您无法在 A 和 B <之间创建直接或子类型关系/ code>（或 A ， B 和一些包含声明的第三类）然后你就没了运气。他们无法分享声明。

If you cannot create a direct or subtype relationship between A and B (or A, B and some third class containing the declarations) then you are out of luck. There is no way that they can share declarations.

但是，您可以使用静态导入使其看起来像是共享声明。例如：

However, you can use static imports to make it seem like the declaration is shared. For example:

    public class A {
        // Declaration of the 'array' attribute
        public float[] array = new float[]{1.1f, 2.2f, 3.3f};

    }


    import static A.array;
    class B {
        // now I can use 'array' without qualifying it with 'A'
    }

顺便说一句，使用 static 变量来共享状态通常是一个坏主意，尤其是表示为裸阵列的状态。这显然是非面向对象的。

Incidentally, it is generally a bad idea to use static variables to share state, especially state represented as bare arrays. This is distinctly non-object-oriented.

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