public String getString(String columnName, String defaultValue) {
        int index = getColumnIndex(columnName);
        if (isValidIndex(index)) {
            return getString(index);
        } else {
            return defaultValue;
        }
    }
public String getString ( String columnName , String defaultValue ) { int index = getColumnIndex ( columnName ) ; if ( isValidIndex ( index ) ) { return getString ( index ) ; } else { return defaultValue ; } }
Convenience alias to {@code getString\(getColumnIndex(columnName))}. If the column does not
exist for the cursor, return {@code defaultValue}.