Factorial

package menu.com;import android.app.Activity;import android.os.Bundle;import android.text.Editable;import android.view.Menu;import android.view.MenuInflater;import android.view.MenuItem;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;public class JmenuActivity extends Activity { public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); }public boolean onCreateOptionsMenu(Menu menu) { MenuInflater mi=getMenuInflater(); mi.inflate(R.menu.menu, menu);

return true;}public boolean onOptionsItemSelected(MenuItem item) {

if (item.getItemId()==R.id.item1) { Toast.makeText(JmenuActivity.this, "se eligio la obcion",Toast.LENGTH_SHORT).show(); setContentView(R.layout.main); Button Boton = (Button)findViewById(R.id.ok);

final EditText Texto = (EditText)findViewById(R.id.entry); Boton.setOnClickListener(new OnClickListener() { public void onClick(View v) { Toast.makeText(JmenuActivity.this, "El factorial es: " + CalcularFactorial(Texto.getText()), Toast.LENGTH_LONG).show(); } });

} if (item.getItemId()==R.id.item2)

Toast.makeText(JmenuActivity.this, "se ha seleccionado opcion 2",Toast.LENGTH_SHORT).show();

return super.onOptionsItemSelected(item);} private int Factorial( int Numero ) { if( Numero == 1 ) return 1; return Numero * Factorial(Numero - 1); } private String CalcularFactorial( Editable Texty ) { String Cadena; int Numero; Cadena = Texty.toString(); Numero = Factorial(Integer.parseInt(Cadena)); return Integer.toString(Numero); } }

Main.xml<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" > <TextView android:id="@+id/label" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginTop="30dip" android:text = "Escribe el nºmero para calcular su factorial:" /> <EditText android:id="@+id/entry" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_below="@id/label" android:layout_marginTop="30dip" android:background="@android:drawable/editbox_background" /> <Button android:id="@+id/ok" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/entry" android:layout_centerHorizontal="true" android:layout_marginLeft="10dip" android:layout_marginTop="30dip" android:text="CalcularFactorial" /></RelativeLayout>

<?xml version="1.0" encoding="utf-8"?><menu xmlns:android="http://schemas.android.com/apk/res/android" > <item android:id="@+id/item1" android:title="Opcion 1"/> <item android:id="@+id/item2" android:title="Opcion 2"/>

</menu>