Question

所以，我正在创建一个应用程序，其主要目的是计算三角形的面积，周长和内径。用户应该输入三个double类型的值。＆安培;他们点击的任何按钮都应该在结果视图中吐出答案。用户可以单击任何按钮（无论哪个都没关系）。如果他们先点击“区域”按钮＆amp;然后决定点击“周长”按钮，结果应该改变。这是一张图片，让您了解它的样子：（http://tinypic.com/r/v3ncyh/8）。我不确定我是否正确编程，因为我的值看起来完全不正确＆amp;我不认为我的视图与我的代码正确连接。这段代码的第一部分是我的Triangle类，其中包含了我的所有getter / setter＆amp;我计算面积，周长和内径的方法。第二部分是我的Activity，它是我的应用程序的主要（和唯一）活动。

public class Triangle {

// instance variables
private double sideA;
private double sideB;
private double sideC;

// Getters and setters
public double getSideA() {
    return sideA;
}

public void setSideA(double sideA) {
    this.sideA = sideA;
}

public double getSide2B() {
    return sideB;
}

public void setSideB(double sideB) {
    this.sideB = sideB;
}

public double getSideC() {
    return sideC;
}

public void setSideC(double sideC) {
    this.sideC = sideC;
}

// Constructor
public Triangle(double sideA, double sideB, double sideC) {
    this.sideA = sideA;
    this.sideB = sideB;
    this.sideC = sideC;
}

// Three methods...
public double getPerimeter() {

    return sideA + sideB + sideC;
}

public double getArea() {

    double s = 1/2 * (sideA + sideB + sideC);
    double area = Math.sqrt(s*(s-sideA)*(s-sideB)*(s-sideC));

    return area;
}

public double getInRadius() {

    double r = ((-sideA + sideB + sideC)*(sideA - sideB + sideC)*(sideA + sideB - sideC))/(4*(sideA + sideB + sideC));
    double answer = Math.sqrt(r);

    return r;
}

}

public class TriangleComputationActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_triangle_computation);

    // Declare our View variables and assign them the Views from the layout file
    final TextView lengthOne = (TextView) findViewById(R.id.lengthOne);
    final TextView lengthTwo = (TextView) findViewById(R.id.lengthTwo);
    final TextView lengthThree = (TextView) findViewById(R.id.lengthThree);
    final TextView result = (TextView) findViewById(R.id.result);

    Button areaButton = (Button) findViewById(R.id.area);
    Button perimeterButton = (Button) findViewById(R.id.perimeter);
    Button inradiusButton = (Button) findViewById(R.id.inradius);

    final Triangle triangle = new Triangle((double)lengthOne.getInputType(), (double)lengthTwo.getInputType(),(double)lengthThree.getInputType());

    // Methods in Action...
    areaButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            result.setText(triangle.getArea());

        }
    });

    perimeterButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            result.setText(triangle.getPerimeter());
        }
    });

    inradiusButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            result.setText(triangle.getInRadius());
        }
    });

}

Answer 1

TextView.getInputType()不会返回对您有用的值。它与TextView的实际文本无关。

您应该使用TextView.getText()代替。您必须使用Double.parseInt()或Double.valueOf()将其转换为双精度数字。如果是我，我会在那些TextViews上设置android:inputType="numberDecimal"。

我如何计算面积，周长和＆amp;半径与视图

1 个答案: