java - 访问 ArrayList 中对象的属性

Question

我需要构建一个方法来查找给定矩形 ArrayList 中矩形面积的总和。

public class Homework {
public static void main(String[] args) {
    ArrayList<Rectangle> test = new ArrayList<Rectangle>();
    test.add(new Rectangle(10, 20, 30, 40));
    test.add(new Rectangle(10, 10, 30, 40));
    test.add(new Rectangle(20, 20, 40, 50));
    test.add(new Rectangle(20, 10, 50, 30));
    System.out.println(areaSum(test));
    System.out.println("Expected: 5900.0");
    System.out.println(areaAverage(test));
    System.out.println("Expected: 1475.0");
}

public static double areaSum(ArrayList<Rectangle> rects){
    //work goes here
}

到目前为止我所拥有的是:

public static double areaSum(ArrayList<Rectangle> rects){
    double totalArea = 0;
    for (Rectangle r : rects) {
        double area = (x + width) * (y + height);
        totalArea = totalArea + area;
    }
    return totalArea;
}

如何从测试器 block 构建的 ArrayList 中提取矩形的尺寸？我对这个领域有点陌生，这是一项家庭作业，我似乎无法弄清楚。

Answer 1

将计算面积的行更改为:

双面积 = r.getWidth() * r.getHeight();