Question

我想做android应用来计算android上画布的距离点。基本上我有4个点，(x1,y1)(x2,y2),(x3,y3) and (x4,y4).我想要做的是计算最大比率长度，D1比最小长度，D2 ..对于D1，我需要计算两点之间的距离(x1,y1)(x2,y2)对于D2，我需要为点计算另一个点(x3,y3)(x4,y4) ..的距离，它只是用户输入。用户将放置该值并直接计算比率D1 / D2。

有人能帮助我吗？我知道公式，但不知道如何做这个功能。

public class MainActivity5 extends Activity implements OnClickListener {

EditText editText1;
EditText editText2;
EditText editText3;
EditText editText4;
EditText editText5;
EditText editText6;
EditText editText7;
EditText editText8;
Button button1;
TextView tvResult;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_activity5);


      // find the elements
    EditText editText1 = (EditText) findViewById(R.id.editText1);
    EditText editText2 = (EditText) findViewById(R.id.editText2);
    EditText editText3 = (EditText) findViewById(R.id.editText3);
    EditText editText4 = (EditText) findViewById(R.id.editText4);
    EditText editText5 = (EditText) findViewById(R.id.editText4);
    EditText editText6 = (EditText) findViewById(R.id.editText5);
    EditText editText7 = (EditText) findViewById(R.id.editText6);
    EditText editText8 = (EditText) findViewById(R.id.editText7);


    button1 = (Button) findViewById(R.id.button1);

    tvResult = (TextView) findViewById(R.id.tvResult);

    // set a listener
    button1.setOnClickListener((OnClickListener) this);
  }

@Override
public void onClick(View arg0) {
    // TODO Auto-generated method stub

 String x1 = editText1.getText().toString();
 String y1 = editText2.getText().toString();
 String x2 = editText3.getText().toString();
 String y2 = editText4.getText().toString();
 String x3 = editText5.getText().toString();
 String y3 = editText6.getText().toString();
 String x4 = editText7.getText().toString();
 String y4 = editText8.getText().toString();

 //calculating distance
 double dist = Math.sqrt(Math.pow(x1 - x2, 2) + Math.pow(y1- y2, 2));

 //what should i put here
 }

Answer 1

您需要解析字符串，然后才能将它们传递给Math方法。可以使用try-catch块来检查无效的数字个案。

public void onClick(View arg0) {
    try {
        double x1 = Double.parseDouble(editText1.getText().toString());
        double y1 = Double.parseDouble(editText2.getText().toString());
        double x2 = Double.parseDouble(editText3.getText().toString());
        double y2 = Double.parseDouble(editText4.getText().toString());
        double x3 = Double.parseDouble(editText5.getText().toString());
        double y3 = Double.parseDouble(editText6.getText().toString());
        double x4 = Double.parseDouble(editText7.getText().toString());
        double y4 = Double.parseDouble(editText8.getText().toString());

        //calculating distance
        double d1 = Math.sqrt(Math.pow(x1 - x2, 2) + Math.pow(y1- y2, 2));
        double d2 = Math.sqrt(Math.pow(x3 - x4, 2) + Math.pow(y3- y4, 2));

        tvResult.setText(Double.toString(d1/d2));
    } catch (NumberFormatException e) {

    }
}

计算android中画布点的距离

1 个答案: