String array throws index out of bounds exception

Question

Im making an android app and this part is where a cursor will go through a database and store the 'title' section of the table into a string array. This is then called in another class and is used to dynamically show buttons based on the entries. The code for putting the titles into an array is as follows:

public String[] getTitles()
{
    SQLiteDatabase db =getReadableDatabase();
    int numRows = (int) DatabaseUtils.queryNumEntries(db, SPORTS_TABLE_NAME);
    String title;
    String[] titleArray = new String[100];
    String sql = "SELECT Title FROM Sports;";
    Cursor cursor = db.rawQuery(sql, null);
    int i = 1;

    while (cursor.moveToNext()) {

        if(cursor != null && cursor.moveToFirst()) {
            title = cursor.getString(0);
            titleArray[i] = title;
            i++;
        }
        if(cursor != null)
            db.close();

    }
    cursor.close();
    return titleArray;
}

Then it is called with the following code:

int i = 1;

    String[] titlesArray = db.getTitles();
    for(String titles: titlesArray){
        Button btn = new Button(this);
        btn.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
        btn.setId(i);
        btn.setText(titlesArray[i]);
        ll.addView(btn);
        i++;
    }

Been looking for a while and think it needs a fresh pair of eyes.. any ideas?

What I saw at once: if(cursor != null && cursor.moveToFirst()) this will move the cursor to first entry in each iteration of the loop ... and: what if there are more than 100 titles? — Fildor
– Fildor, Commented Nov 12, 2014 at 11:56
java.lang.ArrayIndexOutOfBoundsException at com.example.dbHelper.getTitles(dbHelper.java:171) --- That is the titleArray[i] = title; line — Donnacha
– Donnacha, Commented Nov 12, 2014 at 11:56
btn.setText(titlesArray[i]); should it be btn.setText(titles); ? — Alex F
– Alex F, Commented Nov 12, 2014 at 11:57

Blackbelt · Accepted Answer · 2014-11-12 11:56:20Z

4

what if your query returns more than 100 rows? If think it would be safer to use something like

String sql = "SELECT Title FROM Sports;";
Cursor cursor = db.rawQuery(sql, null);
if (cursor == null)
   return;
String[] titleArray = new String[cursor.getCount()];
 while (cursor.moveToNext()) {
     title = cursor.getString(0);
     titleArray[i] = title;
     i++;  
}

of, better, a Collection.

String sql = "SELECT Title FROM Sports;";
Cursor cursor = db.rawQuery(sql, null);
if (cursor == null)
      return;
ArrayList<String> titleArrayList = new ArrayList<String>();
while (cursor.moveToNext()) {
     title = cursor.getString(0);
     titleArrayList.add(title);       
}

answered Nov 12, 2014 at 11:56

Blackbelt

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