By this we can make multiple calculation function and many more thing.
For example- To find simple interest and compound interest with the help of CheckBox.
Program is-
public class MainActivity extends AppCompatActivity { EditText e1, e2, e3, e4; private CheckBox cb1, cb2; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); e1= (EditText) findViewById(R.id.e1); e2= (EditText) findViewById(R.id.e2); e3= (EditText) findViewById(R.id.e3); e4= (EditText) findViewById(R.id.e4); cb1= (CheckBox) findViewById(R.id.cb1); cb2= (CheckBox) findViewById(R.id.cb2); } public void Perform(View view) { try { double result = 0.0; int p = Integer.parseInt("" + e1.getText()); int r = Integer.parseInt("" + e2.getText()); int t = Integer.parseInt("" + e3.getText()); if (cb1.isChecked()) { result = (p * r * t) / 100.0; } if (cb2.isChecked()) { double A = p * Math.pow((1 + r / 100.0), t); result = A - p; } if (cb1.isChecked()&cb2.isChecked()) { double result1 = (p * r * t) / 100.0; double A = p * Math.pow((1 + r / 100.0), t); double result2 = A - p; result= result1+result2; } e4.setText("" + result); } catch (Exception ex) { System.out.println(ex); e4.setText(ex.getMessage()); } } } REsult-