android绘制带有尺寸的矩形，并在运行时对其进行修改

Question

我正在为android开发一个工程应用程序。问题是我需要画：矩形，由矩形制成的图形，以及它们的尺寸。然后，如果你触摸一个维度的一个极端，你就可以使矩形的那个维度更长或更短。

为了实现我的目标，我正在实施下一个计划：

class DrawFigureWithDimensions extends View{
    // implementation of the draw methods
    // ...
    class Rectangles{
        // characterization of the attributes needed for each "rectangle"
        // ...
        class DimensionPositionType{ ... }
        class DimensionExtremeType{ ... }
}
class DrawRectangleWithDimension extends DrawFiguresWithDimensions{ ... }
class DrawBoxWithDimension extends DrawFiguresWithDimensions{ ... }
...

然后，我在实现DimensionPositionType和DimensionExtremeType的内部类时遇到了问题，我找不到如何以合适的方式声明它们。我需要能够在扩展类中决定，比如DrawRectangleWithDimensions，我需要什么类型的维度极限：固定的还是可移动的。类似这样的东西：

public class DrawRectangleWithDimensions extends DrawFiguresWithDimensions {
public DrawRectangleWithDimensions(Context context) {
    super(context);
}
public void setFigure(double width, double height) {
    figureRectangles = new Rectangle[1];
    figureRectangles[0] = new Rectangle(0, 0, width, height);
    figureRectangles[0].setHorizontalDimensionLeftExtremeType(FIXED);
    figureRectangles[0].setHorizontalDimensionRightExtremeType(MOVABLE);
}

例如，这是我为内部类DimensionExtremeType:编写的代码

    class DimensionExtremeType{
        boolean FIXED;
        boolean MOVABLE;
        DimensionExtremeType(String arg){
            if(arg == "FIXED"){
                setFixedExtreme();
            }else if(arg == "MOVABLE"){
                setMovableExtreme();
            }
        }
        public void setFixedExtreme(){
            FIXED = true;
            MOVABLE = false;
        }
        public void setMovableExtreme(){
            FIXED = false;
            MOVABLE = true;
        }
        public String getDimensionExtremeType(){
            if(FIXED==true){
                return "FIXED";
            }else if(MOVABLE==true){
                return "MOVABLE";
            }else {
                return null;
            }
        }
    }

Answer 1

我只知道类枚举的存在，它解决了我的设计问题。这是一种更容易实现的方式。根据我在问题措辞中写的例子，这是使用类枚举的代码：

static class Rectangle{
    // ...
    DimensionExtremeType horizontalDimensionLeftExtremeType;
    DimensionExtremeType horizontalDimensionRightExtremeType;
    DimensionExtremeType verticalDimensionUpperExtremeType;
    DimensionExtremeType verticalDimensionLowerExtremeType;    
    // =-=-=-=     DIMENSION POSITION TYPES      =-=-=-=
    public enum DimensionExtremeType{FIXED, MOVABLE}

}

然后，在扩展类中，例如DrawRectanglesWithDimensions:

public class DrawRectangleWithDimensions extends DrawFiguresWithDimensions {
    public DrawRectangleWithDimensions(Context context) {
        super(context);
    }
    public void setFigure(float  width, float height) {
        figureRectangles = new Rectangle[1];
        figureRectangles[0] = new Rectangle(0, 0, width, height);
        figureRectangles[0].horizontalDimensionLeftExtremeType = Rectangle.DimensionExtremeType.FIXED;
        figureRectangles[0].horizontalDimensionRightExtremeType = Rectangle.DimensionExtremeType.MOVABLE;
        figureRectangles[0].verticalDimensionUpperExtremeType = Rectangle.DimensionExtremeType.MOVABLE;
        figureRectangles[0].horizontalDimensionRightExtremeType = Rectangle.DimensionExtremeType.MOVABLE;
    }
}