SQLite Database: Unable to get specific entry data - database

Question

I'm following a tutorial about setting up SQLite database with Android Java. I've created a database and a simple table to contain data about food and its calories. I've setup a few buttons with functions to enter data, view, get information about a specific entry, modify and delete it.
All works well except the button to get a specific entry. When I click on the 'Get Information' button, it's supposed to return with the food name and its calories value, according to the row ID I put.
Can anyone help to look at my code here, to check what's wrong or missing?
Here is the code for the classes. I've excluded some parts which are not related.
Creating the database:
public class FormDatabase
{
public static final String KEY_ROWID = "_id";
public static final String KEY_FOOD = "food_name";
public static final String KEY_CALORIE = "food_calories";
private static final String DATABASE_NAME = "Calories";
private static final String DATABASE_TABLE = "FoodTable";
private static final int DATABASE_VERSION = 2;
private DbHelper ourHelper;
private final Context ourContext;
private SQLiteDatabase ourDatabase;
private static class DbHelper extends SQLiteOpenHelper
{
public DbHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
// TODO Auto-generated constructor stub
}
#Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" +
KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT , " +
KEY_FOOD + " TEXT NOT NULL , " +
KEY_CALORIE + " TEXT NOT NULL);"
);
}
public String getFood(long l) throws SQLException{
// get data of food name
String[] columns = new String[]{ KEY_ROWID, KEY_FOOD, KEY_CALORIE};
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ROWID + "=" + l, null, null, null, null);
if (c != null){
c.moveToFirst();
String food = c.getString(1);
return food;
}
return null;
}
public String getCalorie(long l) throws SQLException{
// get data of food calorie
String[] columns = new String[]{ KEY_ROWID, KEY_FOOD, KEY_CALORIE};
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ROWID + "=" +
l, null, null, null, null);
if (c != null){
c.moveToFirst();
String calorie = c.getString(2);
return calorie;
}
return null;
}
Another class for setting the main page:
public class DatabaseMain extends Activity implements OnClickListener{
Button sqlUpdate, sqlView, sqlModify, sqlGetInfo, sqlDelete;
EditText sqlFood, sqlCalorie, sqlRow;
#Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.database_main);
sqlUpdate = (Button) findViewById(R.id.bSQLUpdate);
sqlFood = (EditText) findViewById(R.id.etSQLFood);
sqlCalorie = (EditText) findViewById(R.id.etSQLCalorie);
sqlView = (Button) findViewById (R.id.bSQLopenView);
sqlView.setOnClickListener(this);
sqlUpdate.setOnClickListener(this);
sqlRow = (EditText) findViewById(R.id.etSQLrowInfo);
sqlModify = (Button) findViewById(R.id.bSQLmodify);
sqlGetInfo = (Button) findViewById(R.id.bgetInfo);
sqlDelete = (Button) findViewById(R.id.bSQLdelete);
sqlDelete.setOnClickListener(this);
sqlModify.setOnClickListener(this);
sqlDelete.setOnClickListener(this);
}
public void onClick(View arg0)
{
// When click on buttons, data entry into database, view, modify and
delete row
switch (arg0.getId())
{
case R.id.bgetInfo:
try {
String s = sqlRow.getText().toString();
long l = Long.parseLong(s);
FormDatabase foodcal = new FormDatabase(this);
foodcal.open();
String returnedFood = foodcal.getFood(l);
String returnedCalories = foodcal.getCalorie(l);
foodcal.close();
sqlFood.setText(returnedFood);
sqlCalorie.setText(returnedCalories);
}catch (Exception e)
{
String error = e.toString();
Dialog d = new Dialog(this);
d.setTitle("This is an error!");
TextView tv = new TextView(this);
tv.setText(error);
d.setContentView(tv);
d.show();
}
break;
}
}
The database_main layout xml:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width ="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/textView1"
android:text="Food"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"/>
<EditText
android:id="#+id/etSQLFood"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="text" >
</EditText>
<TextView
android:id="#+id/textView3"
android:text="Food Calorie"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<EditText
android:id="#+id/etSQLCalorie"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="number" >
</EditText>
<Button
android:text="Update SQLite Database"
android:id="#+id/bSQLUpdate"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</Button>
<Button
android:text="View"
android:id="#+id/bSQLopenView"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</Button>
<TextView
android:id="#+id/textView2"
android:text="Enter Row ID"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<EditText
android:id="#+id/etSQLrowInfo"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="number" >
<requestFocus></requestFocus>
</EditText>
<Button
android:text="Get Information"
android:id="#+id/bgetInfo"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</Button>
<Button
android:text="Edit Entry"
android:id="#+id/bSQLmodify"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</Button>
<Button
android:text="Delete Entry"
android:id="#+id/bSQLdelete"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</Button>
</LinearLayout>

Answer 1

to add a check to your switch statement, add a default case:
switch (arg0.getId())
{
case R.id.bgetInfo:
... do something...
break;
default:
//this will handle everything else
// write out the argument for debugging, eg:
Console.WriteLine(arg0.getId().ToString());
break;
}
this will tell you what is coming through. if arg0.getId() is not R.id.bgetInfo, the event won't fire...

Answer 2

Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ROWID + "=" +
l, null, null, null, null);
instead using above statement use this one
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ROWID + "=?",
new String[] { String.valueOf(l) }, null, null, null, null);