Question

我正在尝试为我的Android应用创建自定义调色板。我开始这样做了：

public class Theme {

    public static final class DARK {
        final static int POSITIVE_GREEN = Color.rgb(0, 200, 0);
        final static int NEGATIVE_RED = Color.rgb(200, 0, 0);
        final static int BACKGROUND_GREEN = Color.argb(255 - 220, 0, 255, 0); //220
        final static int BACKGROUND_RED = Color.argb(255 - 220, 255, 0, 0);
    }

    public static final class PASTEL {
        final static int POSITIVE_GREEN = Color.parseColor("#326262");
        final static int NEGATIVE_RED = etc
        final static int BACKGROUND_GREEN = etc
        final static int BACKGROUND_RED = etc
    }

}

但是当我想重构其中一个字段名称时意识到有些不对劲。字段名称应该是THEME中的抽象或其他东西，但由于这些不应该是可实例化的类，我不能使用这里建议的构造函数： Why not abstract fields? 我该怎么做？

Answer 1

接口的使用似乎很合适：

每个主题都将实现此界面：

public interface Theme {
    int getPositiveGreen(); 
    ...
}

例如：

public class Dark implements Theme {

   private final static int POSITIVE_GREEN = Color.rgb(0, 200, 0);

   public int getPositiveGreen() {
       return POSITIVE_GREEN;
   }
   ....
}

一般来说，公共静态变量的使用应限于一些非常简单的场景，而不是你想要实现的场景。

https://docs.oracle.com/javase/tutorial/java/concepts/interface.html

Answer 2

使用enum而不是int常量您可以改为使用枚举，例如：

public enum DARK {
        POSITIVE_GREEN (0,200, ..){
              void abstractField(){
                 //Achieve your custom methods
              }
        },
        NEGATIVE_RED (200,0, ..){
           //Achieve your custom methods
        },
        BACKGROUND_GREEN (.....){
           //Achieve your custom methods
        },
        BACKGROUND_RED (...){
          //Achieve your custom methods
        },
      

       // Offer (with the Senate) constructor to initialize the fields defined
       DARK (int variable1, int variable2) {
                this.variable1 = variable1;
                this.variable2 = variable2;
       }
       // Define the fields you need
       private int variable1;
       private int variable2;

       //Custom abstract methods you need
       abstract void abstartField();
}

我不知道你是否可以提供帮助

Answer 3

抽象方法只是子类需要提供的函数。

＆＃34;抽象字段＆＃34;可以被认为是一个需要提供的价值

public class Theme {

    public final int POSITIVE_GREEN;
    public final int NEGATIVE_RED;
    public final int BACKGROUND_GREEN;
    public final int BACKGROUND_RED;

    private Theme(int POSITIVE_GREEN, int NEGATIVE_RED, int BACKGROUND_GREEN, int BACKGROUND_RED)
    {
        this.POSITIVE_GREEN = POSITIVE_GREEN;
        this.NEGATIVE_RED = NEGATIVE_RED;
        this.BACKGROUND_GREEN = BACKGROUND_GREEN;
        this.BACKGROUND_RED = BACKGROUND_RED;
    }

    public static final Theme DARK = new Theme(
        Color.rgb(0, 200, 0),
        Color.rgb(200, 0, 0),
        Color.argb(255 - 220, 0, 255, 0),
        Color.argb(255 - 220, 255, 0, 0)
    );

    public static final Theme PASTEL = new Theme( ...

Answer 4

如果您只想要使用名称合约，可以使用以下概念。

public interface Theme {
    public int POSITIVE_GREEN;
    public int NEGATIVE_RED;
    public int BACKGROUND_GREEN;
    public int BACKGROUND_RED;
    public Color getColor(int colorName);
}

public static final class Theme1 extends Theme {
    Map<Integer, Color> colorMap = new HashMap<>();
    private Theme1() {
        colorMap.put(POSITIVE_GREEN, Color.rgb(0, 200, 0));
        colorMap.put(NEGATIVE_RED, Color.rgb(200, 0, 0));
        colorMap.put(BACKGROUND_GREEN, Color.argb(255 - 220, 0, 255, 0));
        colorMap.put(BACKGROUND_RED, Color.argb(255 - 220, 255, 0, 0));
    }

    @Override
    public Color getColor(int colorName) {
        return colorMap.get(colorName);
    }
}

静态最终类实现的抽象字段？

4 个答案: