Calcolatrice con Database

Calcolatrice salva le somme eseguite in un database

-------------------CalcolatriceDB.java-------------------

package org.me.calcolatricedb;

import android.app.Activity;
import android.os.Bundle;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.content.Context;
import android.widget.*;
import android.view.View;
import android.content.Intent;

/**
*
* @author lollino360
*/
public class CalcolatriceDB extends Activity {
        private final String DB_NAME="Calcolatrice.db";
        private SQLiteDatabase database = null;
    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.main);
        Button somma=(Button)findViewById(R.id.somma);
        somma.setOnClickListener(somma1);
        creaDB();
        creaTabella();
        Button mostra=(Button)findViewById(R.id.mostra);
        mostra.setOnClickListener(onMostra);
        // ToDo add your GUI initialization code here
    }
    private View.OnClickListener somma1=new View.OnClickListener() {
        public void onClick(View v){
            EditText numero1=(EditText)findViewById(R.id.num1);
            EditText numero2=(EditText)findViewById(R.id.num2);
            EditText ris1=(EditText)findViewById(R.id.ris);
            int num1=Integer.parseInt(numero1.getText().toString());
            int num2=Integer.parseInt(numero2.getText().toString());
            int ris=num1+num2;
            String risultato=num1+"+"+num2+"="+ris;
            ris1.setText(risultato);
//            numero1.setText(" ");
//            numero2.setText(" ");
            String inserisci="Insert into conti (operazione) values ('"+risultato+"');";

            try{
                 database.execSQL(inserisci);
             }catch(SQLiteException e){
                 e.printStackTrace();
             }

        }
    };
    public void creaDB(){
        try{
            database=openOrCreateDatabase(DB_NAME,SQLiteDatabase.CREATE_IF_NECESSARY,null);
        }catch(SQLiteException e){
            e.printStackTrace();
        }
    }
    public void creaTabella(){
        try{
            if (database.isOpen()){
                         database.execSQL("CREATE TABLE IF NOT EXISTS conti (_id integer primary key autoincrement, operazione varchar(50));");
            }
        }catch(SQLiteException e){
            e.printStackTrace();
        }
    }
     private View.OnClickListener onMostra=new View.OnClickListener(){
         public void onClick(View v) {
            Intent i = new Intent(v.getContext(), Lista.class);
            startActivity(i);
         }
      };

}

-------------------Lista.java-------------------

package org.me.calcolatricedb;

import android.app.Activity;
import android.os.Bundle;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.content.Context;
import android.widget.*;
import android.view.View;
import android.widget.ListView;
import android.widget.AdapterView;
import android.database.Cursor;
import java.util.ArrayList;
import android.util.Log;
import android.content.Intent;
public class Lista extends Activity {
     private final String DB_NAME = "Calcolatrice.db";
     private SQLiteDatabase database = null;
     private ListView voti;
     ArrayList<String> righe = new ArrayList<String>();
     /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.lista);
         creaDatabase();
         leggiTabellaVoto();
         voti=(ListView)findViewById(R.id.listav);
           // By using setAdpater method in listview we an add string array in list.
         //Log.i("voti="+voti);
         voti.setAdapter(new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1 , righe));
         Button inserisci = (Button) findViewById(R.id.btnGetMoreResults);
         inserisci.setOnClickListener(onInserisci);
    }
    public void creaDatabase(){
         try{
                    database=openOrCreateDatabase(DB_NAME,SQLiteDatabase.CREATE_IF_NECESSARY, null);
          } catch (SQLiteException e) {
                    System.out.println("non ha creato il database studente");
                    e.printStackTrace();
          }
     }
     public void leggiTabellaVoto(){

                    Cursor c=database.query("conti",null,null,null,null,null,null,null);
                     int numRows = c.getCount();
                    c.moveToFirst();
                    for (int i = 0; i < numRows; ++i) {
                              Riga r = new Riga();
                              r._id = c.getLong(0);
                              r.operazione = c.getString(1);
                              System.out.println(r.operazione);
                              righe.add(r.operazione);
                              c.moveToNext();
                    }

     }

     class Riga {
          public long _id;
          public String operazione;
     }
     private View.OnClickListener onInserisci=new View.OnClickListener(){
         public void onClick(View v) {
            Intent i = new Intent(v.getContext(), CalcolatriceDB.class);
            startActivity(i);
         }
      };
     @Override
     public void onDestroy() {
          super.onDestroy();
          database.close();
     }
}

-------------------main.xml-------------------

<?xml version="1.0" encoding="UTF-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:stretchColumns="1"
>
    <TableRow>
        <TextView android:text="numero:"
                  android:layout_width="100px"
                  />
    <EditText
        android:layout_width="200px"
        android:layout_height="wrap_content"
        android:id="@+id/num1"
    />
    </TableRow>
        <TableRow>
        <TextView android:text="numero:"
                  android:layout_width="100px"
                  />
    <EditText
        android:layout_width="200px"
        android:layout_height="wrap_content"
        android:id="@+id/num2"
    />
    </TableRow>
    <TableRow>
        <TextView android:text="Risultato:"
                  android:layout_width="100px"
                  />
    <EditText
        android:layout_width="200px"
        android:layout_height="wrap_content"
        android:id="@+id/ris"
    />
    </TableRow>
        <Button android:id="@+id/somma"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:text="+"
          />
        <Button android:id="@+id/mostra"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:text="Mostra operazioni eseguite"
          />
</TableLayout>

-------------------lista.xml-------------------

<?xml version="1.0" encoding="UTF-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
     >

  <ScrollView
          android:layout_height="fill_parent"
          android:layout_width="fill_parent">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
            >
      <ListView android:id="@+id/listav"
          android:layout_width="fill_parent"
          android:layout_height="300sp"
          android:drawSelectorOnTop="false"
          android:cacheColorHint="#ff6a00"
          android:divider="#ff8f40"
          android:dividerHeight="2px"
          />
      <RelativeLayout
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"
          android:background="#676767"
          android:orientation="vertical">

        <Button
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
           android:id="@+id/btnGetMoreResults"
            android:padding="10px"
            android:text="Inserisci nuovo dato" />
      </RelativeLayout>
      <RelativeLayout
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"
          android:background="#676767"
          android:orientation="vertical">

        <Button
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
           android:id="@+id/btnGetMoreResults1"
             android:visibility="gone"
            android:padding="10px"
            android:text="Mostra detagli" />
      </RelativeLayout>

    </LinearLayout>
  </ScrollView>

</RelativeLayout>

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