Android Open Source - my_training Find P I Activity

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License

The source code is released under:

GNU Lesser General Public License

Java Source Code

package com.example.findpi;
//from ww  w .  j  av a 2  s.  c om
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;

public class FindPIActivity extends Activity {

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


  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.find_pi, menu);
    return true;
  }

  public void onCountButtonClicked(View view) {
    EditText editText = (EditText)findViewById(R.id.EnterNField);
    int iN = Integer.parseInt(editText.getText().toString());
    String PIStr = countPI(iN);
    EditText outputTextField = (EditText) findViewById(R.id.OutputField);
    outputTextField.setText(PIStr);
  }

  private String countPI(int iPILength) {
    StringBuilder result = new StringBuilder(iPILength);
    int size = 10* iPILength / 3;
    int massive[] = new int[size];
    // Initialise massive with 2.
    for (int i = 0; i < size; i++) {
      massive[i] = 2;
    }
    int n = 0;
    // counting Pi...
    while (n < iPILength) {
      int carriedOver = 0;
      int sum = 0;
      for (int i = size - 1; i >= 0; i--) {
        massive[i] *= 10;
        sum = massive[i] + carriedOver;
        int balance = sum / (2*i + 1);
        massive[i] = sum % (2*i + 1);
        carriedOver = balance * i;
      }
      massive[0] = sum % 10;
      int newPiDigit = sum / 10;
      int heldDigits = 0;
      switch (newPiDigit) {
      case 9:
      {
        heldDigits++;
        break;
      }
      case 10:
      {
        newPiDigit = 0;
        for (int i = 1; i <= heldDigits; i++) {
          int replaced = Integer.parseInt(result.substring(n - i, n - i + 1));
          if (replaced == 9) {
            replaced = 0;
          } else {
            replaced++;
          }
          result.deleteCharAt(n - i);
          result.insert(n - i, replaced);
        }
        heldDigits = 1;
        break;
      }
      default:
      {
        heldDigits = 1;
      }
      } // switch
      result.append(newPiDigit);
      n++;
    }
    // adding dot if we wanted to get more than 1 digit
    if (iPILength > 1) {
      result.insert(1, '.');
    }
    return result.toString();
  }
}

Java Source Code List

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