I am trying to display a SQLite table in a view. I want my first column to have a width of 20 characters. I have attempted to achieve this effect by using the substring method but I get stringindexoutofboundsexceptions with strings less than 20 characters. Any help is greatly appreciated. Here is my code:
Method for displaying table in view:
public String getData() {
// TODO Auto-generated method stub
String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_QUANTITY, KEY_VALUE };
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
String result = "";
int iRow = c.getColumnIndex(KEY_ROWID);
int iName = c.getColumnIndex(KEY_NAME);
int iQuantity = c.getColumnIndex(KEY_QUANTITY);
int iValue = c.getColumnIndex(KEY_VALUE);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
result = result + /*c.getString(iRow) + " " +*/ c.getString(iName).substring(0, 20) + " " + c.getString(iQuantity) + " " + c.getString(iValue) + "\n";
}
Just use c.getString(iName).substring(0, Math.min(20, c.getString(iName).length()) (possibly using a temporary for c.getString(iName)) instead of the substring you have now.
If you don't want them then why select. You can just do
String[] columns = new String[]{ KEY_ROWID, "substr(" + KEY_NAME + ",1,20)", KEY_QUANTITY, KEY_VALUE };
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
and get at most 20 chars from the column.
Related
I am trying to make a simple android app that get info of user from database, and I want to separate these info by line between them.
like this:
here is my code:
public String getData() {
// TODO Auto-generated method stub
String[] columns = new String[] { KEY_ID2, KEY_NAME, KEY_EMAIL};
Cursor c = ourDbase.query(TABLE_SCORE, columns, null, null, null, null, null + " DESC");
String result ="";
int iRow = c.getColumnIndex(KEY_ID);
int iName = c.getColumnIndex(KEY_NAME);
int iEmail= c.getColumnIndex(KEY_EMAIL);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
result = result + c.getString(iEmail) + " " + c.getString(iName) + " -" + c.getString(iRow)+ "\n";
}
return result;
}
Do you mean you want something like :
1 Jason j#yahoo.com-2 Mark m#yahoo.com-3 Freya f#yahoo.com
You can do something like :
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
result = result + c.getString(iEmail) + " " + c.getString(iName) + " -" + c.getString(iRow)+ "\n";
result+="-"; //add "-" for each person
}
Please tell me if i miss-understood your question.
UPDATE
Looking from your example, you probably want to use a List of person. If you want this, try :
public List<Person> getData() {
// TODO Auto-generated method stub
String[] columns = new String[] { KEY_ID2, KEY_NAME, KEY_EMAIL};
Cursor c = ourDbase.query(TABLE_SCORE, columns, null, null, null, null, null + " DESC");
List<Person> people = new ArrayList<Person>();
int iRow = c.getColumnIndex(KEY_ID);
int iName = c.getColumnIndex(KEY_NAME);
int iEmail= c.getColumnIndex(KEY_EMAIL);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
Person p = new Person();
p.setEmail(c.getString(iEmail));
//set other info, like id, name
people.add(person);
}
return people;
}
Where person is a new public class with private id,name and email.
UPDATE
public class Person {
private String name, id, email;
//create the name,id, email setter - getter or just make those variables public
}
This is what class Person should look like :
Feel free to ask if you dont understand or i miss understood you.
I have two columns in a database, id and city. How can I get all the city data and put it in a string when the row id is less than 3. I am having difficulty in writing a query to get data when the row id is less than 3. Right now my method gets all the data from the database. Thanks.
String[] columns = new String[]{KEY_ROWID, KEY_CITY};
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
String result =" ";
int iRow = c.getColumnIndex(KEY_ROWID);
int iCity = c.getColumnIndex(KEY_CITY);
for(c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
result = result + c.getString(iCity) + "\n";
}
return result;
String[] columns = new String[]{KEY_ROWID, KEY_CITY};
// "note "rowid" is used in fts tables and "id" in normal tables.
// I'm assuming your constant KEY_ROWID chose the correct one.
String where = KEY_ROWID + " <= " + 3;
Cursor cursor = ourDatabase.query(DATABASE_TABLE, columns, where, null, null, null, null);
if(!cursor.moveToFirst()){
Log.e("System.out", "cursor is empty");
}else{
int ix_city = cursor.getColumnIndexOrThrow(KEY_CITY);
StringBuilder sb = new StringBuilder();
do{
String city = cursor.getString(ix_city);
Log.i("System.out", "city name " + city);
if(TextUtils.isEmpty(city))
continue;
sb.append(city).append("\n");
}while(cursor.moveToNext());
Log.i("System.out", "the entire list " + sb.toString());
}
i am using this method to get the price of all item that has a category name value bt it is not showing anything...
public long getcostmain(String xyz)throws SQLException {
// TODO Auto-generated method stub
String[] columns = new String[]{KEY_ROWID, KEY_CATEGORY,KEY_DATE,KEY_PRICE,KEY_DETAILS};
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_DATE + "=" + xyz, null, null, null, null);
long cost = 0;
for(c.moveToFirst(); ! c.isAfterLast(); c.moveToNext()){
cost = cost + c.getLong(3);
}
return cost;
}
In your code, when you query data from your database, you need to change your code to following:
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_DATE + "='" + xyz +"'", null, null, null, null);
You need to put ' mark around your xyz string.
I'm a noob to android and im am trying to query a sqlite table. I have read several tutorials and know how to query a table to return an entire column of values, but i can't seem to figure out how to query a just a single value from a column by string. Any help is greatly appreciated. here is my code:
My successful code to query and return values for entire column:
public String getValue() {
// TODO Auto-generated method stub
String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_QUANTITY, KEY_OUNCES, KEY_VALUE };
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
String result = "";
int iRow = c.getColumnIndex(KEY_ROWID);
int iName = c.getColumnIndex(KEY_NAME);
int iQuantity = c.getColumnIndex(KEY_QUANTITY);
int iOunces = c.getColumnIndex(KEY_OUNCES);
int iValue = c.getColumnIndex(KEY_VALUE);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
result = result + /*c.getString(iRow) + " " +*/ c.getString(iValue) + "\n";
}
return result;
}
My attempt to query column for single value by string:
public String getSingleValue(String aCoin) throws SQLException{
// TODO Auto-generated method stub
String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_QUANTITY, KEY_OUNCES, KEY_VALUE};
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_NAME + "=" + aCoin, null, null, null, null);
String result = "";
int iRow = c.getColumnIndex(KEY_ROWID);
int iName = c.getColumnIndex(KEY_NAME);
int iQuantity = c.getColumnIndex(KEY_QUANTITY);
int iOunces = c.getColumnIndex(KEY_OUNCES);
int iValue = c.getColumnIndex(KEY_VALUE);
if (c != null){
c.moveToFirst();
result= c.getString(1);
return result;
}
return null;
}
Change this
String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_QUANTITY, KEY_OUNCES, KEY_VALUE };
to
String[] columns = new String[]{ KEY_NAME};
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_NAME + "=" + aCoin, null, null, null, null);
String result = "";
if (c != null){
c.moveToFirst();
result= c.getString(0);
return result;
}
return null;
If you want to only get the name column.
I am currently creating a database to store a list of names and coordinates of service stations. However I cannot view the database when i click the view button. Here is my code: `
public String getData()
{
// TODO Auto-generated method stub
String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_COORDINATES};
Cursor c = myDatabase.query(DATABASE_NAME, columns, null, null, null, null, null);
String result = "";
int iRow = c.getColumnIndex(KEY_ROWID);
int iName = c.getColumnIndex(KEY_NAME);
int iCoordinates = c.getColumnIndex(KEY_COORDINATES);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext())
{
result = result + c.getString(iRow) + " " + c.getString(iName) + " " + c.getString(iCoordinates) + "\n";
}
return result;
}`
Does anybody see a problem with this code?
Your cursor might not contain any rows. If so, c.getString() will throw exception.
moveToFirst() returns false on error. Do your loop like this:
if (c.moveToFirst())
{
do
{
result = result + c.getString(iRow) + " " + c.getString(iName) + " " + c.getString + "\n";
} while (c.moveToNext())
}
then you can deal with why your table has no rows if this is in fact the case...